Samacheer Kalvi Class 11 Bio Zoology Solutions Chapter 4 Organ and Organ Systems in Animals

I. Choose The Best Options

Part I

 

Question 1. The clitellum is a distinct part in the body of earthworm Lampito mauritii, it is found in?
(a) Segments 13-14
(b) Segments 14-17
(c) Segments 12 -13
(d) Segments 14-16
Answer: (b) Segments 14-17
In simple words: The clitellum is a thick, band-like part on an earthworm's body that helps in reproduction, and in Lampito mauritii, it is located on segments 14 to 17. This special ring of skin produces a cocoon for eggs.

🎯 Exam Tip: Remember the specific segment numbers for the clitellum, as this is a common detail asked in identification and characteristic questions.

 

Question 2. Sexually, earthworms are
(a) Sexes are separate
(b) Hermaphroditic but not self - fertilizing
(c) Hermaphroditic and self - fertilizing
(d) Parthenogenic
Answer: (b) Hermaphroditic but not self - fertilizing
In simple words: Earthworms have both male and female reproductive organs in the same body (hermaphroditic), but they cannot fertilize themselves. They need another earthworm to mate and exchange sperm. This ensures genetic diversity.

🎯 Exam Tip: Distinguish between being hermaphroditic (having both sexes) and capable of self-fertilization, as these are different biological concepts.

 

Question 3. To sustain themselves, earthworms must guide their way through the soil using their powerful muscles. They gather nutrients by ingesting organic matter and soil, absorbing what they need into their bodies. Say whether the statement is True or False: The two ends of the earthworm can equally ingest soil.
(a) True
(b) False
Answer: (b) False
In simple words: Earthworms only have a mouth at one end (the anterior end) to eat soil. They cannot eat from both ends of their body. Their digestive system is one-way.

🎯 Exam Tip: Understand the basic anatomy of an earthworm, specifically that feeding occurs only through the mouth at the anterior end, not equally from both ends.

 

Question 4. The head region of Cockroach ..................... pairs of ..................... and ..................... shaped eyes occur.
(a) One pair, sessile compound and kidney shaped
(b) Two pairs, stalked compound and round shaped
(c) Many pairs, sessile simple and kidney shaped
(d) Many pairs, stalked compound and kidney shaped
Answer: (a) One pair, sessile compound and kidney shaped
In simple words: A cockroach's head has one pair of eyes that are compound (made of many small units), not on stalks, and look like kidney beans. These help them see a wide area.

🎯 Exam Tip: Remember the key features of cockroach eyes: they are compound, sessile (fixed), and kidney-shaped.

 

Question 5. The location and numbers of malpighian tubules in Periplaneta.
(a) At the junction of midgut and hindgut, about 150.
(b) At the junction of foregut and midgut, about 150.
(c) Surrounding gizzard, eight.
(d) At the junction of colon and rectum, eight.
Answer: (a) At the junction of midgut and hindgut, about 150.
In simple words: In a cockroach (Periplaneta), tiny tubes called Malpighian tubules, around 150 of them, are found where the middle part of the gut joins the back part. They work like kidneys, helping to remove waste.

🎯 Exam Tip: Pinpoint the exact junction (midgut and hindgut) and the approximate number (100-150) for Malpighian tubules, as both details are important.

 

Question 6. The type of vision in Cockroach is
(a) Three dimensional
(b) Two dimensional
(c) Mosaic
(d) Cockroachdonot have vision
Answer: (c) Mosaic
In simple words: Cockroaches have mosaic vision, which means their eyes create an image by combining many small images, almost like a puzzle. This gives them a wide, but not very sharp, view of their surroundings.

🎯 Exam Tip: Understand that mosaic vision, while offering a wide field of view, typically results in lower resolution compared to other vision types.

 

Question 7. How many abdominal segments are present in male and female Cockroaches?
(a) 10,10
(b) 9,10
(c) 8,10
(d) 9,9
Answer: (d) 9,9
In simple words: Both male and female cockroaches have nine visible segments in their abdomen. This segmentation is a key characteristic of their body structure.

🎯 Exam Tip: Pay close attention to gender-specific differences in anatomy; however, for abdominal segments, males and females often share similar counts in some species.

 

Question 8. Which of the following have an open circulatory system?
(a) Frog
(b) Earthworm
(c) Pigeon
(d) Cockroach
Answer: (d) Cockroach
In simple words: A cockroach has an open circulatory system, meaning its blood (hemolymph) flows freely inside its body cavity and around its organs, not just inside blood vessels. This is different from humans who have blood always in vessels.

🎯 Exam Tip: Remember that insects, like cockroaches, typically possess an open circulatory system where hemolymph bathes the tissues directly, unlike the closed systems of vertebrates.

 

Question 9. Buccopharyngeal respiration in frog
(a) is increased when nostrils are closed
(b) Stops when there is pulmonary respiration
(c) is increased when it is catching fly
(d) stops when mouth is opened.
Answer: (b) Stops when there is pulmonary respiration
In simple words: Buccopharyngeal respiration, where a frog breathes using its mouth lining, pauses or stops when the frog starts using its lungs for breathing. This is one of the ways frogs can breathe in different situations.

🎯 Exam Tip: Focus on the dual nature of frog respiration; they use different methods depending on whether they are in water or on land, and one method can take over from another.

 

Question 10. Kidney of frog is
(a) Archinephros
(b) Pronephros
(c) Mesonephros
(d) Metanephros
Answer: (c) Mesonephros
In simple words: The kidneys in an adult frog are of the mesonephros type, which means they are a bit more complex than the earliest kidney forms but not as complex as those in mammals. This kind of kidney helps filter waste from the frog's body.

🎯 Exam Tip: Know the different types of kidneys (pronephros, mesonephros, metanephros) and which vertebrate groups possess each type.

 

Question 11. Presence of gills in the tadpole of frog indicates that
(a) fishes were amphibious in the past
(b) fishes involved from frog -like ancestors
(c) frogs will have gills in future
(d) frogs evolved from gilled ancestor
Answer: (d) frogs evolved from gilled ancestor
In simple words: The fact that frog tadpoles have gills, just like fish, tells us that frogs likely came from ancestors who also had gills and lived in water. It shows a link in evolution.

🎯 Exam Tip: Relate embryonic or larval features (like gills in tadpoles) to evolutionary history and ancestral forms, as these often provide strong evidence for shared ancestry.

 

Question 12. Choose the wrong statement among the following:
(a) In earthworm, a pair of male genital pore is present.
(b) Setae help in the locomotion of earthworms.
(c) Muscular layer in the body wall of an earthworm is made up of circular muscles and longitudinal muscles
(d) Typhlosole is part of the intestine of earthworms.
Answer: (d) Typhlosole is part of the intestine of earthworm.
In simple words: The statement that says typhlosole is a part of the intestine is actually correct. The question asks for the *wrong* statement, but option (d) is a correct fact about earthworms, meaning the question or options are phrased to make a true statement appear as the incorrect choice if not carefully read. Let's assume there's a misunderstanding in the question's premise or options. A typhlosole is indeed an important fold in the intestine that helps absorb food.

🎯 Exam Tip: Always double-check if the question asks for the "correct" or "wrong" statement, as it can easily lead to errors if misread. Also, be aware of specific anatomical terms like typhlosole.

 

Question 13. Which of the following are the sense organs of Cockroach?
(a) Antennae, compound eyes, maxillary palps, anal cerci
(b) Antennae, compound eye, maxillary palps and tegmina
(c) Antennae, ommatidia, maxillary palps, sternum and anal style.
(d) Antennae, eyes, maxillary palps, and tarsus of walking legs and coxa
Answer: (a) Antennae, compound eyes, maxillary palps, anal cerci
In simple words: Cockroaches use their antennae to feel and smell, their compound eyes to see, maxillary palps to taste and touch around their mouth, and anal cerci to sense vibrations and air movement. These are all their important sense organs.

🎯 Exam Tip: For sense organs, remember that insects often have multiple types of receptors, including tactile (antennae, palps), visual (compound eyes), and vibrational (cerci).

II. Very Short Questions

 

Question 14. What characteristics are used to identify the earthworms?
Answer: Earthworms can be found in gardens by their fecal deposits, known as worm castings, on the soil surface. They can be identified by these characteristics:
- They have a long and cylindrical narrow body.
- They show bilateral symmetry, meaning their body can be divided into two similar halves.
- They are light brown and often have a purple tint at their front end.
- Their body is divided into many segments, also called metameres.
- The top side (dorsal surface) has a dark line running down the middle.
- In mature worms, segments 14-17 are swollen with a thick, glandular skin called the clitellum. This clitellum is important for reproduction.
In simple words: You can spot earthworms by the little mounds of soil they leave and their long, brown, segmented body. They have a special swollen band (clitellum) when they are fully grown.

🎯 Exam Tip: When describing physical characteristics, use precise biological terms like "bilateral symmetry" and "metameres" to show a deeper understanding.

 

Question 15. What are earthworm casts?
Answer: Earthworm casts are the undigested food particles, mixed with soil, that earthworms pass out through their anus. These are also known as vermicasts and are a sign of earthworm activity, enriching the soil.
In simple words: Earthworm casts are the tiny piles of soil and leftover food that earthworms poop out after digesting organic matter. They are good for the soil.

🎯 Exam Tip: Connect earthworm casts to their ecological role; they are not just waste but also contribute to soil fertility and aeration.

 

Question 16. How do earthworms breathe?
Answer: Earthworms breathe in a simple way because:
- They do not have lungs or gills like other animals.
- They breathe directly through their moist skin.
- The blood vessels close to the surface of their skin help to exchange gases (taking in oxygen and releasing carbon dioxide). This process is called cutaneous respiration.
In simple words: Earthworms breathe through their skin. They don't have lungs or gills. Oxygen goes into their blood through their wet skin.

🎯 Exam Tip: Highlight "moist skin" and "cutaneous respiration" as key terms when explaining earthworm respiration, emphasizing the direct exchange of gases.

 

Question 17. Why do you call cockroaches a pest?
Answer: Cockroaches are considered pests because:
- They destroy food and contaminate it with their unpleasant odor.
- They carry many types of harmful bacteria that can cause diseases.
- The allergens from cockroaches can trigger asthma in people who are sensitive. These combined factors make them a nuisance and a health risk.
In simple words: Cockroaches are pests because they spoil food, smell bad, carry germs that cause sickness, and can even trigger asthma.

🎯 Exam Tip: Focus on the specific negative impacts of cockroaches: food contamination, disease transmission, and allergic reactions (asthma).

 

Question 18. Comment on the functions of alary muscles?
Answer: The alary muscles are triangular muscles located on both sides of the heart in some insects like cockroaches. These muscles are mainly responsible for helping with blood circulation by causing contractions that assist in moving hemolymph throughout the body. They act as supportive structures for the heart.
In simple words: Alary muscles are triangle-shaped muscles next to the heart that help push blood around the body in some insects.

🎯 Exam Tip: Remember that alary muscles are associated with the heart in insects and play a role in their open circulatory system by aiding hemolymph movement.

 

Question 19. Name the visual units of the compound eyes of cockroach.
Answer:
- The photoreceptors of the cockroach consist of a pair of compound eyes on the upper (dorsal) surface of its head.
- Each compound eye is made up of about 2000 simple eyes, which are called ommatidia. These ommatidia are the individual light-sensing units.
In simple words: The tiny visual units that make up a cockroach's compound eye are called ommatidia. There are about 2000 of these in each eye.

🎯 Exam Tip: Be precise with terminology: "compound eye" refers to the whole organ, while "ommatidia" are its individual functional units.

 

Question 20. How does the male frog attract the female for mating?
Answer: Male frogs attract females for mating using two main features:
- The male frog has a pair of vocal sacs and a special nuptial pad (also called a copulatory pad) on the underside (ventral side) of the first digit of each front limb.
- The vocal sacs produce loud croaking sounds to call females. The nuptial pad helps the male hold onto the female during mating.
In simple words: Male frogs croak loudly using vocal sacs to attract females. They also have a special pad on their front leg to hold the female during mating.

🎯 Exam Tip: When describing mating behaviors, ensure you mention both the auditory signals (vocal sacs and croaking) and the physical adaptations (nuptial pad) if applicable.

 

Question 21. Write the types of respiration seen in frogs.
Answer: Frogs can breathe in two different ways, depending on whether they are in water or on land.
- In water, their skin acts as an aquatic respiratory organ, which is called cutaneous respiration. Oxygen dissolved in the water passes through their skin by diffusion.
- On land, the frog uses its buccal cavity (mouth lining), skin, and lungs to breathe. In buccal respiration, the mouth stays closed but the nostrils remain open. The floor of the mouth moves up and down, drawing air in and pushing it out through the nostrils. Respiration using the lungs is called pulmonary respiration. The lungs are pink, elongated, sac-like structures in the upper part of their chest. Air enters through the nostrils into the buccal cavity and then moves into the lungs. During lung use, gas exchange occurs in the lungs.
In simple words: Frogs can breathe through their skin in water (cutaneous respiration) and on land. On land, they also use their mouth lining (buccal respiration) and lungs (pulmonary respiration).

🎯 Exam Tip: Clearly differentiate between cutaneous, buccal, and pulmonary respiration, stating where each occurs (water/land) and the primary organ involved.

 

Question 22. Differentiate between peristomium and prostomium in earthworms.
Answer:

The prostomium helps the earthworm to push into the soil and gather food.
In simple words: The peristomium is the first body part that holds the mouth. The prostomium is a small fleshy part that covers the mouth, helping the worm burrow and eat.

🎯 Exam Tip: Remember that the peristomium is the actual body segment, while the prostomium is a pre-oral lobe or flap, distinct from a true segment.

 

Question 23. Give the location of clitellum and spermathecal openings in Lampito mauritii.
Answer:
- The clitellum in Lampito mauritii is found on segments 14-17.
- There are three pairs of spermathecae, and their openings are located between segments 6/7, 7/8, and 8/9. These openings allow for the reception of sperm from another worm during mating.
In simple words: In Lampito mauritii, the clitellum is on segments 14 to 17. The openings for storing sperm (spermathecal openings) are found between segments 6 and 7, 7 and 8, and 8 and 9.

🎯 Exam Tip: Precisely recall the segment numbers for both the clitellum and spermathecal openings, as these are common points of confusion in earthworm anatomy.

 

Question 24. Differentiate between tergum and a sternum.
Answer:

These plates, along with pleurites on the sides, form the exoskeleton of insects, providing protection and support.
In simple words: Tergum is the hard plate on the top of an insect's body segment, like a shield on its back. Sternum is the hard plate on the bottom side of the body segment, protecting its belly.

🎯 Exam Tip: Visualize the insect body; "tergum" relates to the dorsal (top) surface, while "sternum" relates to the ventral (bottom) surface of each segment.

 

Question 25. Head of cockroach is called hypognathous. Why?
Answer: The head of a cockroach is called hypognathous because its mouthparts are directed downwards. The head itself is small and triangular, and it is positioned at a right angle to the main body axis. This downward-facing arrangement of mouthparts is characteristic of the hypognathous type.
In simple words: A cockroach's head is called hypognathous because its mouth parts point downwards. It's like their mouth is under their head.

🎯 Exam Tip: Remember that "hypognathous" specifically refers to mouthparts directed downwards, which is typical for ground-feeding insects like cockroaches.

 

Question 26. What are the components of blood in frogs?
Answer: The blood of frogs is made up of several key components:
1. Plasma: This makes up about 60% of the blood volume. It is the liquid part.
2. Blood cells: These account for approximately 40% of the blood volume and include:
- Red blood cells (RBCs): These carry oxygen.
- White blood cells (WBCs): These are part of the immune system.
- Platelets: These help in blood clotting.
In simple words: Frog blood has mainly plasma (the liquid part) and blood cells. The cells include red cells for oxygen, white cells for fighting sickness, and platelets for stopping bleeding.

🎯 Exam Tip: For blood composition, always list plasma and the three main types of cellular components (RBCs, WBCs, platelets) along with their approximate proportions or primary functions.

 

Question 27. Draw a neat labeled diagram of the digestive system of frog.
Answer: The question asks for a diagram of the digestive system of a frog. (Note: A complex biological diagram like the digestive system of a frog cannot be accurately rendered in simple inline SVG code with the provided template or tools. Therefore, the diagram is referenced but not recreated.)
In simple words: This question asks to draw and label the frog's digestive system. This involves showing parts like the mouth, esophagus, stomach, and intestines.

🎯 Exam Tip: When drawing biological diagrams, always include a clear title and label all significant parts accurately. Practice drawing frequently to master these questions.

 

Question 28. Explain the reproductive system of frog
1. Male reproductive organ:
Answer: (Note: The diagram for the male reproductive system of a frog cannot be accurately rendered in simple inline SVG code with the provided template or tools. Therefore, the diagram is referenced but not recreated.)
- The male frog has a pair of testes. Each testis is connected to the kidney and the dorsal body wall by a peritoneal membrane called mesorchium.
- The vasa efferentia, which arise from each testis, open into the bladder canal. This canal then connects to the urinogenital duct that comes out of the kidneys and opens into the cloaca.
2. Female reproductive system: (Note: The diagram for the female reproductive system of a frog cannot be accurately rendered in simple inline SVG code with the provided template or tools. Therefore, the diagram is referenced but not recreated.)
- The female frog has paired ovaries attached to the kidney and dorsal body wall by folds of peritoneum called mesovarium.
- Each oviduct has a funnel-like opening called ostia at its front end, which leads into the body cavity. Towards the back, the oviducts widen to form an ovisac before opening into the cloaca.
- Fertilization in frogs is external.
- The eggs hatch into tadpoles.
- Tadpoles develop three pairs of gills, which allow them to breathe underwater.
- The tadpole then grows into an air-breathing, carnivorous adult frog through a process called metamorphosis.
In simple words: Male frogs have testes connected to kidneys, which link to a tube leading to the cloaca for reproduction. Female frogs have ovaries connected to oviducts that widen into ovisacs, also leading to the cloaca. Frogs lay eggs that hatch into gilled tadpoles, which then change into adult frogs.

🎯 Exam Tip: When describing reproductive systems, differentiate between male and female structures and highlight key processes like external fertilization and metamorphosis in frogs.

Part II

Additional Important Questions and Answers

I. Choose The Best Options

 

Question 1. We can locate the earth worm's living area through ....................
(a) Small hole in the ground
(b) Worm costings
(c) Debris
(d) Excreta of cattle
Answer: (b) Worm costings
In simple words: You can find where earthworms live by looking for the small piles of soil they leave on the surface, which are called worm castings. These are like their footprints on the ground.

🎯 Exam Tip: Connect observable signs like worm castings directly to the presence and activity of earthworms, showing an understanding of their ecological impact.

 

Question 2. The region between 14 – 17 segments in earthworm is called as ....................
(a) Pygidium
(b) Prostomium
(c) Clitellum
(d) Peristomium
Answer: (c) Clitellum
In simple words: The special swollen part of an earthworm's body, located between segments 14 and 17, is called the clitellum. This part is important for making cocoons for eggs.

🎯 Exam Tip: Precisely recall the segment range (14-17) for the clitellum, as this is a specific anatomical detail frequently tested.

 

Question 3. What is the shape of the setae?
(a) 'S' shaped
(b) C shaped
(c) Round shaped
(d) Curved shaped
Answer: (a) 'S' shaped
In simple words: The tiny bristles on an earthworm's body, called setae, are shaped like the letter 'S'. This unique shape helps them grip the soil and move around.

🎯 Exam Tip: Focus on the characteristic 'S' shape of setae and its functional importance in earthworm locomotion.

 

Question 4. Find the correct pair.
(a) First segment -Clitellum
(b) Last segment – Peristomium
(c) 14-17 -Pygidium
(d) Vascular fold -Typhlosole
Answer: (d) Vascular fold -Typhlosole
In simple words: The typhlosole is a special fold inside the earthworm's intestine that has many blood vessels. It helps the worm absorb more nutrients from its food.

🎯 Exam Tip: Understand the functions of specific anatomical parts; the typhlosole is a key feature of the earthworm's digestive system for increasing absorptive surface area.

 

Question 5. In which segment the lateral hearts are situated?
(a) 7-13
(b) 6-13
(c) 6-15
(d) 7-15
Answer: (a) 7-13
In simple words: The lateral hearts, which are like small pumping organs in an earthworm's circulatory system, are found in segments 7 through 13. They help push blood around the body.

🎯 Exam Tip: For earthworm circulatory anatomy, remember the location of lateral hearts (sometimes called "pseudohearts") in specific segments (7-13) as they are crucial for blood circulation.

 

Question 6. Find out the correct statement
(a) In male cockroach the reproductive sac lie anteriorily.
(b) In female cockroaches chitinous plates gonapophyses are present around the female genital aperture.
(c) In male cockroach the sternum of 10th segment have pair of anal cerci.
(d) In the 12th segment anal styes are seen.
Answer: (b) In female cockroaches chitinous plates gonapophyses are present around the female genital aperture.
In simple words: Female cockroaches have hard plates called gonapophyses that are located around their opening for reproduction. These plates are an important part of their anatomy.

🎯 Exam Tip: Pay close attention to distinguishing features between male and female organisms when answering questions about reproductive anatomy.

 

Question 7. What is the length of lampito mauritii.
(a) 80-210 mm
(b) 85-350 mm
(c) 80 - 220 mm
(d) 80 - 200 mm
Answer: (a) 80-210 mm
In simple words: The earthworm called Lampito mauritii can grow to be between 80 and 210 millimeters long. This length varies among different individuals.

🎯 Exam Tip: Remember specific measurements and ranges for key organisms, as these details often appear in objective questions.

 

Question 8. The pale brown the purplish tinge colour of earthworm is due to the pigment
(a) Haemolymph
(b) Porphyrin
(c) Choloroquin
(d) Flaemoglobin
Answer: (b) Porphyrin
In simple words: The slight purplish-brown color seen in earthworms comes from a special substance inside their bodies called porphyrin. This pigment gives them their unique hue.

🎯 Exam Tip: When asked about coloration or unique physical characteristics, identify the specific pigment or structural feature responsible.

 

Question 9. In which segments the spermatheca are situated
(a) 6-7 segments, 7-8 segments 8-9 segments
(b) 6-7 segments, 8-9 segments 9-10 segments
(c) 8-9 segments, 9-10 segments 10-11 segments
(d) 7-8 segments, 8-9 segments 9-10 segments
Answer: (a) 6-7 segments, 7-8 segments 8-9 segments
In simple words: The spermatheca, which stores sperm, are located in the earthworm's body within segments 6-7, 7-8, and 8-9. They are important for reproduction.

🎯 Exam Tip: Accurately identifying the exact segments where reproductive organs are found is crucial for questions on earthworm anatomy.

 

Question 10. Find out the wrong statement?
(a) The wall of earthworm is thin and moist.
(b) There are cuticle and epithelial layer.
(c) The body cavity which lies between the digestive system and body wall does not act as a fluid-filled structure.
(d) The coelomic fluid is alkaline and milky in nature.
Answer: (c) The body cavity which lies between the digestive system and body wall does not act as a fluid-filled structure.
In simple words: The false statement is that the body cavity between the gut and body wall is not filled with fluid. Actually, this cavity in earthworms contains fluid and acts like a skeleton.

🎯 Exam Tip: For "wrong statement" questions, read each option carefully and identify the one that contradicts known biological facts.

 

Question 11. Whether the following statement is correct or wrong. Justify.
(a) In earthworm the digestive tract runs from the mouth to anus.
(b) In earthworm the mouth is seen in the first segment.
(c) In the second segment lies buccal cavity.
(d) Pharynx is found in the 4th segment or pharyngeal region and the pharynx. The pharynx leads into the oesophagus, which leads into the gizzard. The gizzard connects to the crop, which is followed by the intestine. The intestine opens into the anal opening or anus via a small muscular pharynx.
Answer: (b) True, True, True, True
In simple words: All four statements are correct. The digestive tube goes from mouth to anus, the mouth is in the first part, the buccal cavity is in the second part, and the pharynx is in the fourth part, leading to the esophagus and other parts.

🎯 Exam Tip: When a question asks to justify true/false statements, ensure you understand why each part is correct or incorrect based on anatomical facts.

 

Question 12. The large complex molecules which consist of organic-rich soil eaten by earthworm with the help of digestive enzymes is converted into the simple absorptive unit is
(a) Intestinal digestion
(b) Digestion
(c) Rectal digestion
(d) Enzymatic digestion
Answer: (b) Digestion
In simple words: When an earthworm eats organic-rich soil, its body breaks down the big, complex food molecules into smaller, simpler parts using digestive chemicals. This process is simply called digestion.

🎯 Exam Tip: Understand that digestion is the general process of breaking down food, while specific types like "intestinal digestion" refer to where it happens.

 

Question 13. Find the odd one out. The earthworm receptors are
(a) Photoreceptors
(b) Vision receptors
(c) Taste receptors
(d) Gustatory receptors
Answer: (b) Vision receptors
In simple words: Earthworms have photoreceptors (for light), taste receptors, and gustatory receptors (which also deal with taste). However, they do not have vision receptors, meaning they cannot truly "see" images like humans.

🎯 Exam Tip: Knowing the specific types of receptors an animal possesses helps differentiate it from others, especially when identifying the "odd one out."

 

Question 14. Which of the following is true with an excretory system of earthworm.
(a) Nephridia
(b) Nephron minute tubules
(c) Nephridia – minute coiled tubules
(d) Nephron – coiled tubule
Answer: (c) Nephridia – minute coiled tubules
In simple words: The excretory system of an earthworm uses nephridia, which are tiny, coiled tubes that help remove waste. These tubules are specialized for this function.

🎯 Exam Tip: Understand that nephridia are the fundamental excretory units in earthworms, and they are characterized by their minute, coiled tubular structure.

 

Question 15. Apart from nephridia, there is specialised cell present in the intestinal walls.
(a) Chlorogogen
(b) Chloricgen
(c) Chlorajan
(d) Chlorojin
Answer: (a) Chlorogogen
In simple words: Besides nephridia, earthworms have special cells called chloragogen cells in their intestine walls. These cells play a role in excretion, similar to how a liver works.

🎯 Exam Tip: Remember specific cell types and their functions, especially those that contribute to multiple physiological processes like excretion in earthworms.

 

Question 16. What is the other name for the seminal funnel?
(a) Ciliary
(b) Ciliary rosettes
(c) Ciliary flagella
(d) Ciliary antennae
Answer: (b) Ciliary rosettes
In simple words: The seminal funnel, which collects sperm in earthworms, is also known as ciliary rosettes. These structures are lined with tiny hair-like cilia.

🎯 Exam Tip: Be aware of alternative names or descriptive terms for anatomical structures, as questions might use either one.

 

Question 17. How many days are taken by the earthworm to complete its life cycle?
(a) 70 days
(b) 65 days
(c) 69 days
(d) 60 days
Answer: (d) 60 days
In simple words: An earthworm typically takes about 60 days, or roughly two months, to complete its entire life cycle from egg to adult. This is a general duration for many species.

🎯 Exam Tip: Knowing the duration of life cycles for various organisms is a common factual question, so memorize these key figures.

 

Question 18. What is the fluid manure of earthworm consist of?
(a) Vermicomposting
(b) Vermiculture
(c) Vermiwash
(d) Earthworm manure
Answer: (c) Vermiwash
In simple words: The liquid fertilizer collected from earthworm farming, which includes their excretions and dissolved organic matter, is called vermiwash. It is different from the solid compost or the farming process itself.

🎯 Exam Tip: Differentiate between vermicomposting (the process), vermiculture (earthworm farming), and vermiwash (the liquid product) when discussing earthworm-related agricultural terms.

 

Question 19. Find out the unrelated one
(a) Vermi compose
(b) Vermin
(c) Vermiculture
(d) Vermi wash
Answer: (b) Vermin
In simple words: "Vermin" refers to pests or troublesome animals, which is very different from "vermicompost" (earthworm compost), "vermiculture" (earthworm farming), and "vermiwash" (liquid fertilizer from earthworms), all of which are related to beneficial uses of earthworms.

🎯 Exam Tip: Understand the specific terminology used in topics like vermiculture and be able to identify terms that do not belong to that context.

 

Question 20. Match and find out correct
(a) I - a, II - b, III - c, IV - d
(b) I-d, II-c, III-b, IV-a
(c) I-a, II-c, III-d,IV-b
(d) I - b, II - a, III - c, IV - d
Answer: (b) I-d, II-c, III-b, IV-a
In simple words: The correct matching combination is I with d, II with c, III with b, and IV with a. This means each part is correctly paired with its corresponding description.

🎯 Exam Tip: For matching questions, it's often helpful to match the pairs you are most confident about first, then use elimination for the remaining options.

 

Question 21. Find out the wrong pair of cockroaches.
(a) Tarsus - Podomeres
(b) Genital opening Sclerites – Parametabolus
(c) Sclerites of the dorsal side – Tergites
(d) Sclerites of the ventral side – Sternites
Answer: (b) Genital opening Sclerites – Parametabolus
In simple words: The incorrect pair is "Genital opening Sclerites – Parametabolus" because Parametabolus refers to a type of insect development, not a part of the genital opening sclerites. The other pairs correctly describe parts of a cockroach.

🎯 Exam Tip: Be careful with terms that sound similar or are related to general insect biology but don't specifically describe the paired structure in the question.

 

Question 22. Find out the wrong pair of cockroaches.
(a) Spiracles – Stigmata
(b) Ostia - Colourless coelomic fluid
(c) Ostia – Digestive system cockroach
(d) Supra oesophageal ganglion – Brain
Answer: (c) Ostia – Digestive system cockroach
In simple words: The wrong pair is "Ostia – Digestive system cockroach." Ostia are small openings in the heart that allow blood to enter, related to the circulatory system, not the digestive system. All other pairs are correct.

🎯 Exam Tip: Clearly distinguish between the different organ systems (circulatory, digestive, nervous) and the structures associated with each.

 

Question 23. Which is the ancient organism of insect?
(a) Cockroach
(b) Cricket
(c) Grasshopper
(d) Scorpion
Answer: (a) Cockroach
In simple words: Among the options, the cockroach is known to be a very old type of insect, existing on Earth for millions of years. This makes it an ancient insect.

🎯 Exam Tip: Recognize specific examples of ancient or "living fossil" organisms in zoology, as they highlight evolutionary history.

 

Question 24. Cockroach belongs to period about 320 million years ago.
(a) Devonian
(b) Carboniferous
(c) Missisipian
(d) Pensylvanian.
Answer: (b) Carboniferous
In simple words: Cockroaches first appeared during the Carboniferous period, which was around 320 million years ago. This shows how long these insects have been around.

🎯 Exam Tip: Link organisms to their geological periods of origin to understand their evolutionary timeline.

 

Question 25. One of the fastest moving land insect is the cockroach. What is it's speed?
(a) 6.4 km/hr
(b) 5.0 km/hr
(c) 5.4 km/hr
(d) 6.5 km/hr
Answer: (c) 5.4 km/hr
In simple words: Cockroaches are known for their speed, and they can run as fast as 5.4 kilometers per hour. This speed helps them escape danger quickly.

🎯 Exam Tip: While exact speeds might seem minor, questions on unique adaptations or record-breaking facts often include such specific numerical details.

 

Question 26. Which makes the wings of insect?
(a) Chitin
(b) Pecten
(c) Cellulose
(d) Hemicellulose
Answer: (a) Chitin
In simple words: The wings of insects are primarily made of a strong, lightweight material called chitin. Chitin also forms their outer skeleton, providing structure and protection.

🎯 Exam Tip: Remember that chitin is a key structural polysaccharide found in the exoskeleton of insects, crustaceans, and the cell walls of fungi.

 

II. Very Short Questions

 

Question 1. Name the earthworms of India.
Answer: Some common earthworm species found in India include Lampito mauritii, Perionyx excavatus, and Metaphire posthuma (also known as Pheretima Posthuma). These species are vital for soil health.
In simple words: Earthworms like Lampito mauritii, Perionyx excavatus, and Metaphire posthuma are found in India.

🎯 Exam Tip: When asked to list examples, ensure you provide accurate scientific names or common names as specified.

 

Question 2. What are the regions of clitellum?
Answer: The clitellum region in earthworms can be divided into three parts: the preclitellar region (segments 1st - 13th), the clitellar region itself (segments 14th - 17th), and the post-clitellar region (after the 17th segment). The clitellum is a swollen, glandular band important for reproduction.
In simple words: The clitellum area has three parts: before the clitellum (segments 1-13), the clitellum itself (segments 14-17), and after the clitellum (after segment 17).

🎯 Exam Tip: Clearly delineate the segments for each region to demonstrate a precise understanding of earthworm anatomy.

 

Question 3. Describe locomotion and where is it seen?
Answer: Locomotion in earthworms happens with the help of setae. These small, bristle-like structures are present in all body segments except the very first, the very last, and the clitellum. Each segment contains a ring of chitinous setae that help the earthworm move by anchoring to the soil. Movement involves muscular contractions and extensions.
In simple words: Earthworms move using small bristles called setae. These setae are found in rings on most body segments, helping the worm grip and pull itself along.

🎯 Exam Tip: When describing locomotion, always mention both the structures involved (setae, muscles) and the mechanism of movement (contraction/extension).

 

Question 4. What is the composition of the coelom of earthworms?
Answer: The coelomic fluid of earthworms is milky and alkaline. It is made up of various cell types, including granulocytes, eleocytes, amoebocytes, mucocytes, and leucocytes. These cells perform different functions like immunity and regeneration within the coelomic fluid. This fluid also helps maintain body shape.
In simple words: The fluid inside an earthworm's body cavity is milky and alkaline. It contains many different cells like granulocytes, amoebocytes, and white blood cells.

🎯 Exam Tip: Focus on both the physical properties (milky, alkaline) and the cellular components of the coelomic fluid when answering this question.

 

Question 5. Classify earthworms based on their ecological strategies
Answer: Earthworms are classified into three ecological groups based on their living habits: epigeics, anecics, and endogeics. Epigeics are surface dwellers, like Perionyx excavatus and Eudrilus eugeniae. Anecics live in the upper soil layers, such as Lampito mauritii and Lumbricus terrestris. Endogeics, like Octochaetona thursoni, are found in deeper soil layers, creating vertical burrows.
In simple words: Earthworms are grouped by how they live: epigeics stay on the surface, anecics live in the top soil layers, and endogeics live deep inside the soil.

🎯 Exam Tip: When classifying, always provide the classification categories and an example for each category to score full marks.

 

Question 6. What are the mouthparts of the cockroach?
Answer: The mouthparts of a cockroach are designed for biting and chewing. They consist of several structures: a labrum (upper lip), a pair of mandibles (jaws), two pairs of maxillae, a labium (lower lip), and a hypopharynx (tongue). These parts work together to process food. The mandibles are strong and toothed for grinding food.
In simple words: Cockroaches have biting and chewing mouthparts. These include an upper lip (labrum), strong jaws (mandibles), two sets of maxillae, a lower lip (labium), and a tongue (hypopharynx).

🎯 Exam Tip: When listing anatomical parts, ensure you mention all the primary structures and, if possible, their main function.

 

Question 7. Give notes on sclerites?
Answer: In insects like cockroaches, the exoskeleton is made of hardened plates called sclerites. These sclerites cover each segment of the body and are joined together by a thin, flexible articular membrane, also known as arthrodial membrane. This structure provides both protection and flexibility. They are made of chitin.
In simple words: Sclerites are hard plates that form the outer skeleton of insects. They are joined by a flexible membrane, giving the insect both protection and movement.

🎯 Exam Tip: Emphasize that sclerites provide rigidity, while the articular membranes allow for movement, which is essential for insect mobility.

 

Question 8. When is cockroach evolved?
Answer: Cockroaches are considered very old insects, having evolved and dated back to the Carboniferous period, approximately 320 million years ago. This long evolutionary history makes them one of the most ancient groups of insects. They have adapted well over time.
In simple words: Cockroaches are ancient insects; they first appeared around 320 million years ago, during the Carboniferous period.

🎯 Exam Tip: Providing the specific geological period and approximate age reinforces the answer about the evolutionary timeline of an organism.

 

Question 9. Name the five segments of the leg of the cockroach?
Answer: The leg of a cockroach consists of five main segments: 1. Coxa (Large), 2. Trochanter (Small), 3. Femur (Long and broad), 4. Tibia (Long and thick), and 5. Tarsus (which has five movable joints). These segments allow for a wide range of movement, enabling quick locomotion.
In simple words: A cockroach leg has five parts: Coxa, Trochanter, Femur, Tibia, and Tarsus.

🎯 Exam Tip: Listing all segments in the correct order is important when asked to name parts of an anatomical structure.

 

Question 10. Where are hepatic caeca seen in cockroaches?
Answer: Hepatic caecae in cockroaches are located at the junctional region of the gizzard. There are eight finger-like tubular blind processes, also known as enteric caecae, that extend from this area. They help in digestion and secretion of digestive enzymes.
In simple words: Hepatic caecae are found where the gizzard and midgut meet in cockroaches. They are eight finger-like tubes.

🎯 Exam Tip: Specify both the location (junction of gizzard) and the characteristic appearance (finger-like tubular blind processes) for clarity.

 

Question 11. Trace the air paths of respiration.
Answer: The path of air during respiration in an organism like a cockroach involves several structures: Spiracle
\( \implies \) Trachea
\( \implies \) Tracheoles
\( \implies \) Tissues. This system efficiently delivers oxygen directly to the tissues. It's an open system.
In simple words: Air enters through spiracles, goes into tracheas, then to tiny tracheoles, and finally reaches the body tissues.

🎯 Exam Tip: When tracing a pathway, use arrows or the "implies" symbol to clearly show the correct sequence of structures involved.

 

Question 12. Write a note on coelom of earthworm.
Answer: Earthworms possess a large body cavity called the coelom, which lies between the alimentary canal and the body wall. This coelom is filled with a milky and alkaline coelomic fluid. The fluid and the coelomocytes within it serve as a hydrostatic skeleton, aiding in movement and maintaining body shape. Coelomocytes also play crucial roles in regeneration, immunity, and wound healing. These cells protect the worm from infections.
In simple words: The coelom is the body cavity of an earthworm, filled with a milky, alkaline fluid. It acts like a skeleton and helps with movement, healing, and fighting off sickness.

🎯 Exam Tip: Highlight the dual role of the coelom and its fluid: providing structural support (hydrostatic skeleton) and contributing to physiological processes (immunity, regeneration).

 

Question 13. What are the structures that is not present in frog?
Answer: In frogs, several structures commonly found in other animals are absent. Specifically, frogs do not have an external ear, a distinct neck, or a tail in their adult stage. These features are lost or adapted for their amphibious lifestyle. Tadpoles, however, do have tails.
In simple words: Frogs do not have outer ears, a neck, or a tail when they are adults.

🎯 Exam Tip: When answering about absent structures, it's helpful to also briefly mention any adaptive reasons or developmental stages where they might be present (like a tadpole's tail).

 

Question 14. Give notes on chyme?
Answer: Chyme is the partially digested food that results from the action of hydrochloric acid and gastric juices in the stomach. Once food is mixed with these strong digestive fluids, it becomes a thick, acidic liquid. This chyme then moves from the stomach into the small intestine for further digestion. Its acidic nature helps break down food more effectively.
In simple words: Chyme is the mushy, partly digested food that leaves the stomach. It's mixed with stomach acid and juices.

🎯 Exam Tip: Clearly define chyme as "partially digested food" and mention its key characteristics (acidic, liquid) and the agents that form it (acid, gastric juices).

 

Question 15. What are the regions of nervous system?
Answer: The nervous system can be divided into three main regions: the Central Nervous System (CNS), the Peripheral Nervous System (PNS), and the Autonomous Nervous System (ANS). Each part has specific roles in controlling body functions and responding to stimuli. These systems work together to coordinate all body activities.
In simple words: The nervous system has three main parts: the Central Nervous System, the Peripheral Nervous System, and the Autonomous Nervous System.

🎯 Exam Tip: When listing components of a system, ensure you include all the primary divisions for a comprehensive answer.

 

Question 16. A cockroach produces nutritionally dense milk to feed their young ones. It may be considered as a superfood of the future. How?
Answer: Certain species of cockroaches, specifically *Diploptera punctata*, produce a highly nutritious "milk" that contains crystalline milk. This milk is packed with proteins, fats, and sugars, making it extremely dense in nutrients. Because of its rich composition, it is being studied as a potential superfood for human consumption in the future. It's a unique adaptation for nourishing offspring.
In simple words: Some cockroaches make a special milk that has lots of nutrients, like tiny crystals. Because it's so full of good things, people think it could be a powerful food for humans in the future.

🎯 Exam Tip: For "how" questions, explain the mechanism or reasoning behind the phenomenon, specifying the unique characteristics (crystalline milk, nutritional density).

 

Question 17. What are the economic importance of frog?
Answer: Frogs have several economic benefits. They feed on insects, which helps to control insect pest populations in agriculture, acting as a natural pest control agent. Additionally, frogs are used in traditional medicine for various purposes, including controlling blood pressure and for their anti-aging properties. They also serve as a food source in some cultures.
In simple words: Frogs are helpful because they eat insects, which keeps pests away from crops. They are also used in some old medicines for things like blood pressure and anti-aging.

🎯 Exam Tip: When discussing economic importance, focus on direct benefits to humans or the environment that have economic value.

 

Question 18. What are the types of cockroach?
Answer: There are various types of cockroaches, with some common examples including the American cockroach (*Periplaneta americana*), the Brown-banded cockroach (*Supella longipalpa*), the German cockroach (*Blattella germanica*), and the Viviparous cockroach. These different types are found in various environments and have distinct characteristics. The Viviparous cockroach, *Diploptera punctata*, gives birth to live young.
In simple words: Common types of cockroaches are the American, Brown-banded, German, and Viviparous cockroaches.

🎯 Exam Tip: When listing types, try to include a variety of common examples or mention defining characteristics if the list is short.

 

Question 19. Name the cells that helps in excretion of cockroach?
Answer: Several cells and structures help in the excretion of cockroaches. These include fat bodies, nephrocytes, the cuticle, and urecose glands. The Malpighian tubules are the primary excretory organs, but these other cells also contribute to waste removal. This complex system ensures efficient waste management.
In simple words: Fat bodies, nephrocytes, the cuticle, and urecose glands are cells that help cockroaches get rid of waste from their bodies.

🎯 Exam Tip: Distinguish between primary excretory organs (like Malpighian tubules, though not listed as a cell here) and specialized cells that aid in excretion.

 

Question 20. Define uricotelic organism.
Answer: A uricotelic organism is an animal that eliminates its nitrogenous wastes primarily in the form of uric acid. Uric acid is a relatively insoluble compound, allowing for water conservation, which is especially beneficial for animals living in dry environments. For example, cockroaches are uricotelic. This method of excretion is an adaptation to terrestrial life.
In simple words: A uricotelic organism is an animal that removes its waste nitrogen as uric acid. This helps them save water, like cockroaches do.

🎯 Exam Tip: When defining biological terms, always include a clear definition, mention a key characteristic (e.g., water conservation for uric acid), and provide a relevant example.

 

Question 21. What is typhiosole?
Answer: The typhlosole is an internal fold located in the dorsal wall of the earthworm's intestine, extending into its cavity. This fold is rich in blood vessels and significantly increases the absorptive surface area of the intestine, allowing for more efficient nutrient absorption. It is a key adaptation for digestion in earthworms.
In simple words: The typhlosole is a fold inside an earthworm's intestine. It has many blood vessels and helps the worm absorb more food.

🎯 Exam Tip: Explain both the structure (fold in dorsal wall of intestine) and its primary function (increasing surface area for absorption) for a complete definition.

 

Question 22. What are the glands seen in male reproductive system ?
Answer: In the male reproductive system, several glands are observed, including the mushroom-shaped gland and the conglobate gland. These glands play a role in producing substances that support sperm and aid in reproduction. For example, the mushroom-shaped gland helps in the formation of spermatophores (sperm packets).
In simple words: In the male reproductive system, you can find glands like the mushroom-shaped gland and the conglobate gland. They help in making substances needed for reproduction.

🎯 Exam Tip: When listing glands, try to briefly mention their general function or significance in the reproductive process.

 

Question 23. What is clitellum?
Answer: The clitellum is a distinct, swollen band of glandular skin found on segments 14-17 of mature earthworms. This glandular thickening is crucial for reproduction as it secretes mucus and albumin, which are used to form the cocoon where eggs are deposited. It is a temporary structure that is more prominent during breeding season.
In simple words: The clitellum is a thick, swollen band on an adult earthworm's skin. It makes the cocoon where the eggs are laid.

🎯 Exam Tip: Always mention the clitellum's location (segments 14-17) and its primary role (cocoon formation) for a comprehensive answer.

 

Question 24. Where is spermathecal openings seen in the earthworm?
Answer: The spermathecal openings in earthworms are located intersegmentally, meaning they lie between the grooves of the segments. Specifically, they are found in the grooves of segments 6/7, 7/8, and 8/9. These openings allow for the reception of sperm from another earthworm during mating. There are three pairs of spermathecae.
In simple words: In earthworms, the openings for the spermatheca are found in the grooves between segments 6 and 7, 7 and 8, and 8 and 9.

🎯 Exam Tip: Precision in stating the intersegmental locations (e.g., "between 6/7") is important for questions on earthworm anatomy.

 

Question 25. Where is genital openings seen in the earthworm?
Answer: In earthworms, the genital openings are located in specific segments. The female genital aperture is found on the ventral side of the 14th segment. A pair of male genital apertures are situated latero-ventrally in the 18th segment. These openings facilitate the exchange of gametes during reproduction. Earthworms are hermaphrodites, possessing both.
In simple words: The female reproductive opening is on segment 14, and the two male reproductive openings are on segment 18 of the earthworm.

🎯 Exam Tip: Differentiate clearly between the locations of male and female genital apertures, specifying both segment number and position (ventral, latero-ventral).

 

Question 26. Name the body muscles of earthworm.
Answer: The body of an earthworm includes a cuticle, which is its outer protective layer. The muscular layers beneath the epidermis consist of outer circular muscles and inner longitudinal muscles. These muscle layers work antagonistically to allow the earthworm to extend and contract for locomotion.
In simple words: The earthworm body has an outer protective cuticle and two main muscle layers: outer circular muscles and inner longitudinal muscles.

🎯 Exam Tip: When asked about body muscles, specifically mention the circular and longitudinal muscle layers, as these are fundamental to earthworm movement. The cuticle is an outer layer, not a muscle itself.

 

Question 27. Name the cells that make the epidermis?
Answer: The epidermis is made up of several types of cells. These include supportive cells, glandular cells, basal cells, and sensory cells. These different cells work together to form the outer protective layer of the organism.
In simple words: The epidermis is made of supportive, glandular, basal, and sensory cells.

🎯 Exam Tip: Remember the four main types of cells that form the epidermis: supportive, glandular, basal, and sensory cells.

 

Question 28. What are the functions of coelomocytes of earthworm?
Answer: Coelomocytes in earthworms have important roles. They help in regeneration, which means growing back lost body parts. They also provide immunity, protecting the earthworm from diseases, and assist in wound healing. These cells are like the internal defense and repair team for the earthworm.
In simple words: Coelomocytes help earthworms regenerate, fight sickness, and heal injuries.

🎯 Exam Tip: Key functions of coelomocytes are regeneration, immunity, and wound healing.

 

Question 29. Name the cells of coelom of earthworm
Answer: The coelomic fluid of an earthworm contains several types of cells. These include granulocytes or eleocytes, amoebocytes, mucocytes, and leucocytes. Each cell type plays a specific role in the earthworm's internal functions and defense.
In simple words: The earthworm's coelom contains granulocytes, amoebocytes, mucocytes, and leucocytes.

🎯 Exam Tip: Listing these four types of cells correctly will earn full marks for describing the coelomic fluid composition.

 

Question 31. Give notes on nephrostome.
Answer: The nephrostome is a special funnel-shaped opening found inside the mega nephridium of an earthworm. This internal funnel is completely covered with tiny, hair-like structures called cilia. These cilia help to collect waste fluids from the body cavity.
In simple words: A nephrostome is a ciliated funnel inside the earthworm's mega nephridium that collects waste.

🎯 Exam Tip: Remember that a nephrostome is both internal and fully ciliated, which is key to its function in waste collection.

 

Question 32. What is chloragogen cell?
Answer: Chloragogen cells are special cells found on the coelomic wall of the earthworm's intestine, in addition to nephridia. These cells are important because they help the earthworm excrete nitrogenous wastes into its blood. They act somewhat like a liver, processing waste products.
In simple words: Chloragogen cells are special cells on the earthworm's intestine wall that remove nitrogen waste into the blood.

🎯 Exam Tip: Highlight that chloragogen cells are found on the intestinal wall and their primary role is nitrogenous waste excretion.

 

Question 33. What is protandrous?
Answer: Protandry is a reproductive process where an organism's male reproductive organs mature before its female reproductive organs. In earthworms, this means the sperm develops earlier than the ova (eggs). This timing difference helps prevent self-fertilization, even though earthworms have both male and female organs.
In simple words: Protandrous means male organs mature before female organs, preventing self-fertilization.

🎯 Exam Tip: Explain protandry as the maturation of male parts before female parts in the same organism, focusing on how it avoids self-fertilization.

 

Question 38. What is hypognathous?
Answer: Hypognathous describes a type of head position in insects like cockroaches. It means their mouthparts are directed downwards. The head itself is small and triangular, and it sits at a right angle to the body's main axis, making the mouth face the ground.
In simple words: Hypognathous means the mouthparts face downwards, like in a cockroach.

🎯 Exam Tip: The key point for hypognathous is that the mouthparts are oriented downwards, which is typical for ground-feeding insects.

 

Question 39. What are compound eyes?
Answer: Compound eyes are complex eyes found on the head of insects like cockroaches. They consist of a pair of large, fixed, kidney-shaped eyes located on the top of the head. Each compound eye is made up of about 2000 smaller simple eyes, called ommatidia, which together create a mosaic-like vision.
In simple words: Compound eyes are large eyes made of many small units called ommatidia, giving insects mosaic vision.

🎯 Exam Tip: Define compound eyes by mentioning their composition of numerous ommatidia and the resulting mosaic vision.

 

Question 40. Name the segments of the legs of cockroach?
Answer: The legs of a cockroach are made up of five main segments:
1. Coxa - This is a large segment that attaches the leg to the body.
2. Trochanter - A small, short segment that connects the coxa to the femur.
3. Femur - This is a long and broad segment, like a thigh.
4. Tibia - A long and thick segment, similar to a shin.
5. Tarsus - This segment has five movable joints, which are also called podomeres.
In simple words: Cockroach legs have five parts: coxa (large), trochanter (small), femur (long and broad), tibia (long and thick), and tarsus (five movable joints).

🎯 Exam Tip: List all five segments in order from the body outwards and briefly describe their relative size or shape.

 

Question 41. What is podomeres?
Answer: Podomeres are the small, movable joints that make up the tarsus, which is the last segment of a cockroach's leg. The tarsus typically consists of five such joints, allowing for flexibility and movement of the foot. These joints are essential for the cockroach's grip and movement.
In simple words: Podomeres are the five small, movable joints that form the last part of a cockroach's leg called the tarsus.

🎯 Exam Tip: Clearly state that podomeres are the movable joints of the tarsus, the final leg segment.

 

Question 42. Give notes on wings of cockroach?
Answer: Cockroaches have two pairs of wings. The first pair, called elytra or tegmina, are tough and protective. They cover and shield the second pair of wings when the cockroach is resting. The second, inner pair of wings is used for flight. These hindwings are membranous and fold neatly under the tegmina.
In simple words: Cockroaches have two wing pairs: tough outer wings (tegmina) for protection and inner wings for flying.

🎯 Exam Tip: Distinguish between the two pairs of wings (elytra/tegmina and hind wings) and their respective functions (protection vs. flight).

 

Question 43. Name the plates of the abdomen of cockroach?
Answer: The abdomen of a cockroach has 10 segments, and each segment is covered by hardened plates called sclerites. The sclerites on the dorsal (top) side of the abdomen are known as tergites. Those on the ventral (bottom) side are called sternites, and the plates on the lateral (side) parts are known as pleurites.
In simple words: The cockroach abdomen has 10 segments, each covered by hard plates: tergites (top), sternites (bottom), and pleurites (sides).

🎯 Exam Tip: Clearly identify and differentiate between tergites, sternites, and pleurites based on their position on the abdomen.

 

Question 44. What are the sensory receptors seen in cockroach?
Answer: Cockroaches have several sensory receptors to interact with their environment. These include:
- Antennae, which detect touch and smell.
- Compound eyes, for vision.
- Labrum, the upper lip, which has sensory hairs.
- Mandibles, strong jaws also equipped with sensory cells.
- Labial palps, small sensory appendages near the mouth.
- Anal cerci, tail-like appendages that detect air movements and vibrations.
In simple words: Cockroaches have antennae, compound eyes, labrum, mandibles, labial palps, and anal cerci to sense their surroundings.

🎯 Exam Tip: Enumerate the key sensory structures and briefly mention what each detects or its location.

 

Question 45. Name the fat bodies of cockroach?
Answer: The fat bodies in a cockroach are made up of specialized cells and tissues. These include nephrocytes, cuticle, and urecose glands. These structures play roles in storing nutrients, maintaining the exoskeleton, and contributing to waste management.
In simple words: The cockroach fat bodies contain nephrocytes, cuticle, and urecose glands.

🎯 Exam Tip: List the specific components (nephrocytes, cuticle, urecose glands) that form the fat bodies.

 

Question 46. What are the glands seen in the male cockroach?
Answer: The male cockroach possesses two important glands related to reproduction. These are the mushroom-shaped gland and the conglobate gland. These glands produce substances that are essential for sperm packaging and transferring during mating.
In simple words: Male cockroaches have mushroom-shaped and conglobate glands for reproduction.

🎯 Exam Tip: Focus on the two distinct glands: mushroom-shaped and conglobate, specific to the male cockroach.

 

Question 47. What is meant by paurometabolus?
Answer: Paurometabolous development describes a type of insect life cycle where the development from egg to adult is gradual. In cockroaches, the embryo develops inside an egg case (ootheca) for 5-13 weeks. After hatching, the young ones, called nymphs, look like smaller versions of the adults but lack wings and mature reproductive organs. They grow through several nymphal stages, gradually changing until they become adults.
In simple words: Paurometabolous development means insects grow gradually from egg to nymph to adult, with nymphs resembling mini-adults.

🎯 Exam Tip: Emphasize "gradual development" and that "nymphs resemble adults" but without fully developed wings or reproductive organs.

 

Question 48. What are poikilotherms?
Answer: Poikilotherms are animals whose body temperature changes with the temperature of their surroundings. Unlike warm-blooded animals, they cannot maintain a constant internal body temperature. This means their body temperature goes up when it's hot outside and down when it's cold. Many reptiles, amphibians, and fish are poikilotherms.
In simple words: Poikilotherms are animals whose body temperature changes with the outside temperature.

🎯 Exam Tip: The core definition is "body temperature varies with the environment" – avoid confusing it with ectothermy, which is how they get heat.

 

Question 49. What is nictitating membrane?
Answer: The nictitating membrane is a transparent or translucent third eyelid found in some animals, including frogs. It can be quickly drawn across the eye to protect it from injury, keep it moist, or, in frogs, to see underwater while keeping the eye protected. This specialized eyelid works like a built-in safety shield for the eye.
In simple words: A nictitating membrane is a clear third eyelid that protects the eye and keeps it moist.

🎯 Exam Tip: Mention that it's a "third eyelid" and its main function is "protection" or "keeping the eye moist."

 

Question 51. What is spiracle?
Answer: Spiracles are small, external openings found on the body of insects like cockroaches. These tiny holes connect to a network of tubes called tracheae, which are part of the insect's respiratory system. Cockroaches have 10 pairs of spiracles, allowing air to enter and exit for gas exchange.
In simple words: Spiracles are small holes on an insect's body that let air in and out for breathing.

🎯 Exam Tip: Define spiracles as external respiratory openings connecting to tracheae in insects.

 

Question 52. What is meant by chordotonal receptor?
Answer: A chordotonal receptor is a type of sensory organ found in some insects, such as on the anal cerci of a cockroach. These receptors are specialized to detect vibrations in the air and on the ground. They help the cockroach sense predators or other movements in its surroundings, acting as important warning systems.
In simple words: Chordotonal receptors are sensory organs on anal cerci that detect air and ground vibrations.

🎯 Exam Tip: Key points are its location (anal cerci) and function (detecting vibrations in air and land).

 

Question 53. How can an earthworm sense its burrow?
Answer: An earthworm senses its environment and finds its burrow using specialized receptors located in its prostomium (the fleshy lobe over its mouth). These are thermal receptors, which detect temperature changes, and chemical receptors, which sense different chemicals in the soil. These help the earthworm navigate and locate its home.
In simple words: Earthworms use thermal and chemical receptors in their prostomium to find their burrows.

🎯 Exam Tip: Remember the two types of receptors (thermal and chemical) and their location (prostomium) for navigation.

 

Question 54. Compare the respiration of human with the respiration of cockroach?
Answer: Human respiration uses lungs to breathe in oxygen through the mouth and nose, while cockroaches breathe differently. In cockroaches, their respiratory system consists of spiracles and tracheae. Spiracles are small holes on their body that open and close. During breathing, oxygen enters through these spiracles into the haemocoel (body cavity) via tracheoles, and then gases are exchanged. This direct system delivers oxygen to tissues without using blood for transport.
In simple words: Humans use lungs, but cockroaches breathe through spiracles and tracheae on their body, taking oxygen directly into their body fluids.

🎯 Exam Tip: Highlight the fundamental difference: human lungs vs. cockroach spiracles/tracheae, and direct tissue oxygenation in insects.

 

Question 55. List the very special features of cockroach.
Answer: Cockroaches have some unique features that contribute to their survival. They can survive underwater for up to 45 minutes by holding their breath. They also frequently regulate their breath-holding to control water loss. These adaptations make them highly resilient creatures.
In simple words: Cockroaches can survive underwater for long periods and regulate water loss by holding their breath.

🎯 Exam Tip: Focus on their ability to survive submergence and their method of water regulation through breath control.

 

Question 56. Cockroach can live without its head? How?
Answer: A cockroach can indeed live for about a week without its head. This is because there is no direct connection between its head and its breathing system. Unlike humans, cockroaches do not have nostrils or lungs in their head. Instead, they breathe through 10 pairs of spiracles located on their abdomen. These spiracles are connected to tracheoles and haemolymph, allowing gas exchange to occur even without a head.
In simple words: Cockroaches can live headless for a week because they breathe through spiracles on their abdomen, not through their head.

🎯 Exam Tip: The key reason is that respiration is not head-dependent; gas exchange happens via abdominal spiracles.

 

Question 57. Why is mosaic vision with less resolution in cockroaches?
Answer: Cockroaches have compound eyes, where each eye is made up of hundreds of tiny units called ommatidia. Each ommatidium forms a small, individual image. When all these small images from different ommatidia combine, they create a complete picture, known as mosaic vision. However, because each unit captures only a small part of the scene, this type of vision has less detail or resolution compared to human vision.
In simple words: Cockroach mosaic vision has low resolution because each ommatidium forms only a small part of the whole image.

🎯 Exam Tip: Explain that mosaic vision results from many ommatidia, but the "less resolution" comes from each ommatidium forming only a small, distinct part of the overall image.

 

Question 58. List the characteristic features of order Aneura?
Answer: Aneura is an order of amphibians that includes frogs and toads. Characteristic features include:
- They have elongated hindlimbs, which are very helpful for jumping.
- Many species can live in various environments, including water and on trees.
- Parental care is observed in some species, where parents look after their eggs or young.
In simple words: Aneura (frogs and toads) have long hindlimbs for jumping, can live in water or on trees, and sometimes show parental care.

🎯 Exam Tip: Focus on the most distinctive features: elongated hindlimbs for jumping, habitat flexibility, and presence of parental care.

 

Question 59. Differentiate the compound eyes from simple eye.
Answer:

The way these eyes are built results in very different ways of seeing the world for insects compared to animals with simple eyes.
In simple words: Compound eyes have many small units creating mosaic vision, while simple eyes have one unit forming a single, clear image.

🎯 Exam Tip: Emphasize the "many units, mosaic vision" for compound eyes versus "single unit, clear image" for simple eyes.

 

Question 60. Why three-chambered heart of frog is not as efficient as the four-chambered heart of birds and mammals?
Answer: Birds and mammals have a four-chambered heart, which keeps oxygen-rich (oxygenated) and oxygen-poor (deoxygenated) blood completely separate. This allows highly efficient transport of oxygenated blood to all body parts and sends deoxygenated blood to the purifying organs. In contrast, a frog has a three-chambered heart where oxygenated and deoxygenated blood can mix. This mixed blood then goes to the body, meaning less oxygen reaches the tissues compared to animals with four-chambered hearts. This difference makes the four-chambered heart more efficient at delivering oxygen.
In simple words: A frog's three-chambered heart mixes oxygen-rich and oxygen-poor blood, making it less efficient than the separate circulation in a bird or mammal's four-chambered heart.

🎯 Exam Tip: The critical point is the "mixing of oxygenated and deoxygenated blood" in a three-chambered heart, reducing oxygen delivery efficiency.

 

Question 62. Give notes on setae of earthworm?
Answer: Earthworms have small, hair-like bristles called setae. These setae are made of chitin, not the same material as human hair. They are found in rings on most body segments, except the first and last, and the clitellum. Setae are very important for the earthworm's movement, helping it grip the soil as it crawls. They also play roles in mating and feeling its way around.
In simple words: Setae are small, chitin bristles on earthworms that help them move, mate, and sense their surroundings.

🎯 Exam Tip: Remember that setae are chitinous bristles crucial for locomotion and grip in earthworms.

 

Question 63. Give notes on intestinal caeca of earthworm?
Answer: Intestinal caeca are a pair of cone-shaped outgrowths seen in the 26th segment of the earthworm species *Metaphire posthuma*. These structures are also known as intestinal caecum. They produce amylolytic enzymes, which are special proteins that help digest starch. So, they play a vital role in breaking down food.
In simple words: Intestinal caeca are cone-shaped parts in earthworms that make enzymes to digest starch.

🎯 Exam Tip: Focus on their location (26th segment), shape (cone-shaped), and function (secreting amylolytic enzymes for starch digestion).

III. Short Questions

 

Question 1. Based on their ecological strategies, classify the earthworms?
Answer: Earthworms are classified into different groups based on how they live and interact with their environment:

This classification helps understand their role in soil health and nutrient cycling.
In simple words: Earthworms are grouped by where they live: epigeics on the surface, anecics burrowing deep, and endogeics inside the soil.

🎯 Exam Tip: List all three classifications (Epigeics, Anecics, Endogeics) and provide a characteristic example for each.

 

Question 2. Where is the longest earthworm seen?
Answer: The longest earthworms are found in different regions. *Microchaetus rappi*, an African giant earthworm, can grow to an impressive length of 6.7 meters (22 feet). Another species, *Drawida nilamburansis*, found in Kerala, India, can reach a maximum length of up to 1 meter (3 feet). These examples show the incredible size variation in earthworms.
In simple words: The longest earthworms are *Microchaetus rappi* (6.7 meters) from Africa and *Drawida nilamburansis* (1 meter) from Kerala.

🎯 Exam Tip: Name both specific species and their respective maximum lengths to provide a comprehensive answer.

 

Question 3. What is the significance of coelomic fluid of earthworm?
Answer: The coelomic fluid in earthworms is very important for several reasons. It contains coelomocytes, which are cells vital for the earthworm's health. This fluid helps in regeneration, allowing the earthworm to regrow lost body parts. It also contributes to immunity, protecting against infections, and aids in healing wounds. The fluid also acts as a hydrostatic skeleton, helping the worm maintain its shape and move.
In simple words: Earthworm coelomic fluid helps in regeneration, immunity, and healing wounds, and acts as a skeleton for movement.

🎯 Exam Tip: Mention regeneration, immunity, wound healing, and hydrostatic skeleton function as key significances of coelomic fluid.

 

Question 4. What are the sensory receptors seen in the earthworm?
Answer: Earthworms have various sensory receptors to perceive their environment:
- Photoreceptors: Found on the dorsal (top) surface of the body, these detect light.
- Gustatory receptors: Located in the buccal cavity, these help sense taste.
- Tactile receptors: These sense touch and are distributed across the body surface.
- Chemoreceptors: Seen in the prostomium and body wall, these detect chemical signals.
- Thermoreceptors: These help in sensing temperature changes. These receptors collectively enable the earthworm to navigate, find food, and avoid danger.
In simple words: Earthworms have photoreceptors (light), gustatory (taste), tactile (touch), chemoreceptors (chemicals), and thermoreceptors (temperature).

🎯 Exam Tip: List the different types of receptors and their corresponding senses/stimuli they detect.

 

Question 5. Draw the diagram of nephridia of earthworm and name the parts.
Answer:This diagram shows the basic structure of a nephridium, which is a key excretory organ in earthworms.
In simple words: This picture shows an earthworm's nephridium, which is like its kidney, with a funnel, ciliated passage, and coiled tube.

🎯 Exam Tip: Practice drawing the funnel, ciliated passage, and coiled duct, ensuring clear labels for each part of the nephridium.

 

Question 6. What are the other names for sclerites?
Answer: Sclerites are hardened plates on an insect's exoskeleton, and they have different names based on their location:
- Dorsal sclerites are called tergites (found on the top side).
- Ventral sclerites are called sternites (found on the bottom side).
- Lateral sclerites are called pleurites (found on the side). These different plates connect to form the rigid yet flexible outer covering of the insect.
In simple words: Sclerites on the top are tergites, on the bottom are sternites, and on the sides are pleurites.

🎯 Exam Tip: Clearly list tergites, sternites, and pleurites, linking each to its respective dorsal, ventral, or lateral position.

 

Question 7. The cockroach can survive without its head. Is this statement correct or wrong? If so, give a reason.
Answer: This statement is correct. A cockroach can indeed live for about a week without its head. The main reason is that its breathing system is not located in its head. Cockroaches breathe through small holes called spiracles, located on each segment of their body. Since they have an open circulatory system, their breathing does not depend on the mouth or head.
In simple words: The statement is correct. Cockroaches breathe through body spiracles, not their head, so they can live without it for a while.

🎯 Exam Tip: Confirm the statement's correctness and explain that breathing occurs via spiracles on body segments, not through the head.

 

Question 8. What are the parts of the nervous system?
Answer: The cockroach nervous system includes several key parts. It has a supraoesophageal nerve ganglion, also known as the brain, which is located above the esophagus. There is also a sub-oesophageal ganglion, located below the esophagus. These two are connected by circumoesophageal connectives, forming a ring around the esophagus. A double ventral nerve cord runs down the length of the body, completing the main nervous structure.
In simple words: The cockroach nervous system includes a brain (supraoesophageal ganglion), a sub-oesophageal ganglion, connecting nerves, and a double ventral nerve cord.

🎯 Exam Tip: Identify the key ganglia (supra- and sub-oesophageal), their connections, and the ventral nerve cord.

 

Question 9. What are the significance of nervous system?
Answer: The nervous system in organisms like cockroaches is crucial for many functions. The brain, or supraoesophageal ganglion, acts as a sensory and endocrine center, processing information and producing hormones. The sub-oesophageal ganglion serves as a motor center, controlling the movements of the mouthparts, legs, and wings. Together, these parts coordinate all body activities, allowing the cockroach to respond to its environment, move, and feed.
In simple words: The nervous system's brain handles senses and hormones, while a lower ganglion controls mouth, leg, and wing movements.

🎯 Exam Tip: Differentiate the roles of the brain (sensory/endocrine) and the sub-oesophageal ganglion (motor control of appendages).

 

Question 10. Give notes on ommatidia?
Answer: Ommatidia are the individual light-sensing units that make up the compound eyes of insects like cockroaches. Each ommatidium is a simple eye on its own, equipped with photoreceptors that detect light. A single compound eye can consist of about 2000 such ommatidia, all located on the dorsal (top) surface of the head. Together, they form the insect's mosaic vision.
In simple words: Ommatidia are the many simple light-detecting units that form an insect's compound eye.

🎯 Exam Tip: Highlight that ommatidia are the "simple eyes" that combine to form the "compound eye" and its unique vision.

 

Question 11. Give notes on 'Mosaic vision'?
Answer: Mosaic vision is the type of sight possessed by insects that have compound eyes, such as cockroaches. This vision is formed when each of the hundreds or thousands of individual ommatidia (simple eyes) in a compound eye captures a small, separate part of the overall image. These tiny images combine like pieces of a mosaic. While this vision offers good detection of movement, it generally has lower resolution and is not as clear as the vision produced by a single, large lens in a human eye.
In simple words: Mosaic vision is made of many small images from ommatidia, good for detecting movement but not very clear.

🎯 Exam Tip: Emphasize that mosaic vision results from many small images, providing good motion detection but lower clarity.

 

Question 12. Why is sexual dimorphism exhibited clearly during breeding season in frog?
Answer: Sexual dimorphism, which means visible differences between males and females, becomes very clear in frogs during their breeding season. Male frogs develop a pair of vocal sacs and special nuptial pads on the first digit of each forelimb. The vocal sacs are used to produce loud croaking sounds to attract females. The nuptial pads help the male grip the female during mating. These features are unique to males and are more pronounced during this season to help in successful reproduction.
In simple words: Male frogs show clear differences during breeding season with vocal sacs for croaking and nuptial pads for gripping to attract females.

🎯 Exam Tip: Focus on the specific male features (vocal sacs and nuptial pads) and their roles in attracting females during the breeding season.

 

Question 13. How will you classify the earthworm based on their living in relation to ecological strata?
Answer: Earthworms can be classified into three main groups based on their ecological strategies and where they live in the soil:
1. Epigeics: These are surface-dwelling earthworms, like *Eudrilus eugeniae*. They live in the litter layer and feed on decaying organic matter.
2. Anecics: These earthworms, such as *Lampito mauritii*, create deep, vertical burrows. They come to the surface to feed on organic matter and pull it into their burrows.
3. Endogeics: These earthworms, exemplified by *Octochaetona thurstoni*, live and feed within the mineral soil layers, creating horizontal burrows.
In simple words: Earthworms are classified as epigeics (surface dwellers), anecics (deep burrowers that feed on the surface), and endogeics (soil dwellers).

🎯 Exam Tip: Remember the three ecological classifications: epigeics (surface), anecics (deep vertical burrows, surface feeding), and endogeics (soil dwelling, horizontal burrows).

 

Question 14. Give an account of the respiratory system of earthworm?
Answer: Earthworms do not have special respiratory organs like lungs or gills. Instead, they breathe directly through their moist skin. Respiration happens across the entire body surface. The outer skin is very rich in tiny blood capillaries, which help in the diffusion of gases. Oxygen from the air diffuses through the moist skin into the blood, and carbon dioxide from the blood diffuses out. The earthworm keeps its skin moist with mucus and coelomic fluid to make this gas exchange easy.
In simple words: Earthworms breathe through their moist skin, where oxygen diffuses into blood capillaries and carbon dioxide diffuses out.

🎯 Exam Tip: The key point is "cutaneous respiration" (breathing through skin), which requires a moist body surface and rich blood supply for efficient gas exchange.

 

Question 15. Give an account of the nervous system of earthworm?
Answer: The nervous system of an earthworm is organized around a central nerve cord. At the anterior (front) end, there is a brain, which is a bilobed mass of supra-pharyngeal ganglia. This brain is located in the third segment. A sub-pharyngeal nerve ganglion is found in the fourth segment. These two ganglia are connected by circum-pharyngeal connectives. From the sub-pharyngeal ganglion, a double ventral nerve cord extends backward along the length of the body. This setup allows the earthworm to coordinate its movements and respond to its environment.
In simple words: The earthworm's nervous system includes a brain, a sub-pharyngeal ganglion, connecting nerves, and a double ventral nerve cord.

🎯 Exam Tip: Identify the brain (supra-pharyngeal ganglia), sub-pharyngeal ganglion, circum-pharyngeal connectives, and the double ventral nerve cord as key components.

 

Question 16. What is the excretory organ of earthworm? What are its type?
Answer: The main excretory organs of an earthworm are called nephridia. There are three types of nephridia, categorized by their location and structure:
1. Pharyngeal or tufted nephridia: These are found in segments 5-9.
2. Micro nephridia or Integumentary nephridia: These are present from segments 14 to 19 and continue to the last segment.
3. Mega nephridia or septal nephridia: These are found starting from segment 19 to the last segment. Each type helps remove waste products from the earthworm's body.
In simple words: Earthworms excrete using nephridia, which come in three types: pharyngeal (tufted), micro (integumentary), and mega (septal).

🎯 Exam Tip: Name nephridia as the excretory organ and then list its three types along with their specific segment locations.

 

Question 17. Give notes on vermiwash.
Answer: Vermiwash is a special liquid fertilizer or plant tonic that comes from earthworms. It is used as a spray for leaves to help plants grow better. This liquid contains important nutrients and substances from earthworm excretions and mucus.
In simple words: Vermiwash is a liquid plant food made by earthworms, used to spray on leaves to help plants grow.

🎯 Exam Tip: Remember that vermiwash is a liquid product, different from vermicompost which is solid material.

 

Question 18. What is wormery or wormbin?
Answer: A wormery, also called a wormbin, is a special container where earthworms are used to turn food waste, leaf litter, and other organic matter into good fertilizer. This process creates high-quality compost that helps plants grow well. It's a method of recycling organic waste efficiently.
In simple words: A wormery is a container where worms eat waste and turn it into rich plant food.

🎯 Exam Tip: Wormeries are great for recycling kitchen waste and producing natural fertilizer for gardens.

 

Question 19. Give the systematic classification of earthworm?
Answer: The systematic classification of an earthworm is as follows:
• Phylum - Annelida
• Class - Oligochaeta
• Order - Haplotaxida
• Genus - Lampito
In simple words: Earthworms belong to the Annelida phylum, Class Oligochaeta, Order Haplotaxida, and Genus Lampito, showing their place in the animal kingdom.

🎯 Exam Tip: When listing classifications, always ensure the hierarchy is correct from broadest (phylum) to most specific (genus/species).

 

Question 20. In which part of the cockroach's body the sensory receptors are seen?
Answer: The sensory receptors in a cockroach are found in different body parts, as shown in this table:

In simple words: Cockroaches have different sense organs like antennae for smell, palps for taste, and tiny hairs on their legs and tail-like parts to feel heat and vibrations.

🎯 Exam Tip: Knowing the specific location of each receptor type helps understand how cockroaches perceive their environment and avoid danger.

 

Question 21. Give the systematic classification of frog?
Answer: The systematic classification of a frog is as follows:
• Phylum - Chordata
• Class - Amphibia
• Order - Anura (Aneura is a typo in source)
• Genus - Rana
• Species - Hexadactyla (Hexatacdyla is a typo in source)
In simple words: Frogs belong to the Chordata phylum, Class Amphibia, Order Anura, and Genus Rana, with species like Hexadactyla, showing their biological grouping.

🎯 Exam Tip: Pay attention to correct spelling of scientific names like Anura and Hexadactyla, as even small errors can be marked incorrect.

 

Question 23. Give an account of exo skeleton of cockroach?
Answer: The entire body of a cockroach is covered by a hard, protective outer layer called an exoskeleton, which is made of chitin. In each body segment, this exoskeleton forms hardened plates called sclerites. These sclerites are connected to each other by a thin, flexible membrane called an articular or arthrodial membrane, which allows for movement. The sclerites on the top side (dorsal) are called tergites, while those on the bottom side (ventral) are called sternites. The plates on the lateral, or side, surfaces are known as pleurites.
In simple words: A cockroach has a hard outer shell called an exoskeleton, made of tough plates called sclerites, which are connected by flexible skin to allow it to move.

🎯 Exam Tip: Remember that the exoskeleton provides both protection and support, similar to an internal skeleton but on the outside of the body.

 

Question 24. Give an account of mouth parts of cockroach?
Answer: Cockroaches have mouth parts designed for biting and chewing. These are called mandibulate or orthopterous mouthparts. They include various appendages that help in feeding:
1. A pair of mandibles: These are strong jaws used for crushing food.
2. A pair of maxillae: These help in handling food and pushing it towards the mandibles.
3. Labium (lower lip): This helps hold the food in place.
4. Hypopharynx (tongue): This is a short, fleshy, and flexible part found between the first maxillae, assisting in food manipulation. These parts work together to allow the cockroach to eat a variety of food items.
In simple words: Cockroaches have strong jaws and other small parts around their mouth to bite and chew food.

🎯 Exam Tip: For mouthpart descriptions, listing each part and its primary function will help you score full marks.

 

Question 25. Name the digestive glands of cockroach.
Answer: The digestive glands of a cockroach are:
• Salivary glands: These produce saliva that helps in breaking down food.
• Hepatic caeca (or enteric caeca): These are finger-like structures at the junction of the foregut and midgut that secrete digestive enzymes. These glands play a crucial role in breaking down food into smaller, absorbable molecules.
In simple words: Cockroaches have salivary glands and hepatic caeca, which are special organs that make chemicals to digest their food.

🎯 Exam Tip: Knowing the names and general location of these glands helps understand the cockroach's digestive process.

 

Question 26. Draw the male frog with vocal sac and nuptial pad and marks the parts.
Answer: To draw the male frog, you would include the head, body, and limbs. Key parts to label are the vocal sacs, which are inflatible pouches located on the sides of the throat, and the nuptial pads, which are swollen areas on the inner side of the first digit of the forelimb. These features are important for mating. The diagram would also show the eyes and general body shape.
In simple words: Draw a male frog, pointing out the vocal sacs near its throat and the nuptial pads on its front feet, which it uses during mating.

🎯 Exam Tip: When drawing diagrams, make sure all labels are clear and placed correctly to show the different parts.

 

Question 27. Give an account of buccal cavity of frog.
Answer: The buccal cavity of a frog is its wide mouth opening. Inside, on the floor of this cavity, there is a large, muscular, sticky tongue. This tongue is attached at the front of the mouth and is free at the back, with a forked tip. The upper jaw has small maxillary teeth and vomerine teeth, which are present on each side of the internal nostrils. The lower jaw, however, does not have teeth. This structure helps the frog catch and hold its prey. The buccal cavity leads into the pharynx.
In simple words: A frog's mouth, called the buccal cavity, has a big, sticky tongue attached at the front, small teeth on the upper jaw, and no teeth on the lower jaw, all helping it catch food.

🎯 Exam Tip: Emphasize the tongue's unique attachment and the presence/absence of teeth in the jaws, as these are key distinguishing features.

 

Question 28. Give an account of blood of frog ?
Answer: A frog's blood is made up of two main parts: plasma and blood cells. About 60% of the blood is plasma, which is the liquid part. The remaining 40% consists of various blood cells. These include red blood cells, which carry oxygen; white blood cells, which fight infections; and platelets, which help blood clot. The white blood cells themselves are divided into different types:
1. Neutrophils
2. Basophils
3. Eosinophils
4. Lymphocytes
5. Monocytes
In simple words: A frog's blood has a liquid part called plasma and solid parts like red blood cells (for oxygen), white blood cells (to fight sickness), and platelets (to stop bleeding).

🎯 Exam Tip: When describing blood composition, remember to mention both the liquid component (plasma) and the cellular components (RBCs, WBCs, platelets).

 

IV. Essay Questions

Question 1. Describe the external features of the earthworm?
Answer: Earthworms have a long, cylindrical body. They are usually light brown and range from 80-210 mm in length. Many ring-like grooves divide their body into segments, also called metameres. The mouth is in the middle of the first body segment, which is called the peristomium. A small flap, the prostomium, hangs over the mouth. From segments 14-17, the body becomes swollen and glandular, forming a structure called the clitellum. This helps in forming cocoons. There are pairs of female genital openings in the 14th segment and male genital openings in the 18th segment. In segments 6/7, 7/8, and 8/9, there are spermathecae. All body segments, except the first, last, and the clitellum, have rings of chitinous bristles called setae, which aid in movement. The last segment has the anus. A diagram showing these features would have:
• Anterior end with Prostomium and Mouth.
• Segments 1-13 (Preclitellar region).
• Segments 14-17 (Clitellar region).
• Openings of spermathecae in segments 6/7, 7/8, 8/9.
• Opening of oviduct in 14th segment.
• Opening of vas deferens in 18th segment.
• Setae (bristles) present on segments.
• Posterior end with Anus.
In simple words: Earthworms are long, brown, segmented animals. They have a mouth covered by a small flap, a swollen band called the clitellum for reproduction, and tiny bristles (setae) on most segments that help them move and burrow.

🎯 Exam Tip: When describing external features, cover body shape, size, color, segmentation, and key reproductive and locomotor structures to ensure a comprehensive answer.

 

Question 2. Give an account of digestive system of earthworm?
Answer: The earthworm's digestive system is a straight tube that runs from the mouth to the anus through its entire body. The alimentary canal has several distinct parts:
1. The mouth is in the first segment and opens into a small buccal cavity, which is found in the first and second segments.
2. The thick, muscular pharynx is in the 3rd and 4th segments and is surrounded by pharyngeal glands that produce digestive secretions.
3. A small, narrow esophagus extends from the 5th to the 6th segment.
4. The gizzard, located in the 5th and 6th segments, is muscular and helps grind soil and decaying leaves.
5. The intestine begins from the 7th segment and continues to the last segment, where most digestion and absorption occur.
6. The dorsal wall of the intestine folds inwards to form a vascular cavity called the typhlosole, which increases the surface area for nutrient absorption. A diagram showing this would label:
• Buccal cavity (1-2)
• Pharynx (3-4)
• Oesophagus (5)
• Gizzard (not explicitly shown in diagram but part of system)
• Intestine
• Anus (at the end of the intestine)
In simple words: An earthworm's digestive system is a straight tube with a mouth, pharynx, esophagus, gizzard for grinding food, and a long intestine where food is digested and absorbed, ending at the anus.

🎯 Exam Tip: Highlight the gizzard's role in grinding and the typhlosole's function in increasing absorption area, as these are specific adaptations for earthworm digestion.

 

Question 3. Describe the structure of circulatory system of earthworm?
Answer: Earthworms have a closed type of blood vascular system, meaning blood flows only within blood vessels. This system includes:
• Blood vessels, capillaries, and lateral hearts.
• Two main long blood vessels run along the body: a dorsal vessel (above the alimentary canal) and a ventral vessel (below it).
• Eight pairs of commissural vessels, also called lateral hearts, connect the dorsal and ventral vessels in segments 6-13. These lateral hearts help pump blood.
• The dorsal vessel contains paired valves that prevent blood from flowing backward.
• Blood is pumped from the dorsal vessel to the ventral vessel.
• Blood glands in the anterior segments produce blood cells and hemoglobin, which gives the blood its red color. A diagram would show:
• Dorsal vessel
• Ventral vessel
• Lateral hearts (commissural vessels)
• Connections between vessels in different segments.
In simple words: Earthworms have a closed blood system where blood stays in vessels. A dorsal vessel, a ventral vessel, and eight pairs of "hearts" called lateral hearts, pump the red blood all around the body.

🎯 Exam Tip: Clearly state that the earthworm has a closed circulatory system and mention the role of lateral hearts in pumping blood.

 

Question 4. Describe the structure of reproductive system of earthworm ?
Answer: Earthworms are hermaphrodites, meaning each individual has both male and female reproductive organs. These organs are located in specific segments.
**Male reproductive system:**
• Two pairs of testes are found in segments 10 and 11. These give rise to sperm-producing cells called spermatogonia.
• Two pairs of seminal funnels, which are ciliated structures called ciliary rosettes, are located near the testes in the same segments. They collect sperm.
• Three pairs of spermathecae are present in segments 7, 8, and 9. These store sperm from another earthworm after mating.
• The vas deferens arises from the ciliary rosettes and extends to the 18th segment, where it opens to the outside through the male genital aperture. This opening contains two pairs of penial setae.
• A pair of prostate glands in segments 18 and 19 produce a cement-like substance that bundles sperm into spermatophores.
**Female reproductive system:**
• A pair of ovaries is located in the 12th segment. Ovarian funnels are present.
• Oviducts open into the body cavity at the anterior end with a funnel-like opening called ostia. Posteriorly, the oviducts widen to form ovisacs before opening into the cloaca at the 14th segment as a female genital opening.
• Spermatozoa are received during copulation.
• Three pairs of spermathecae also lie in segments 7, 8, and 9.
• During copulation, eggs mature in nutritive fluid and are deposited into cocoons formed by the clitellum. These cocoons also collect sperm from the partner.
• Fertilization and development happen inside the cocoon.
• Baby earthworms hatch after about three weeks.
A diagram showing the male reproductive system would include:
• Spermathecae (in segments 7, 8, 9)
• Seminal funnel
• Testis (in segments 10, 11)
• Vas deferens
• Ovary (in segment 12, for female system)
• Oviduct
• Opening of oviduct
• Prostate gland (in segments 18, 19)
• Male genital opening
A diagram for the female system would show:
• Oviductal funnel
• Ovary
• Oviduct
• Ureter
• Urinary bladder
• Cloacal aperture (female genital opening)
In simple words: Earthworms have both male and female parts in one body. Male parts include testes for sperm and glands for packaging it. Female parts include ovaries for eggs and tubes to carry them. They mate to exchange sperm, and eggs are laid in cocoons where they develop.

🎯 Exam Tip: Clearly distinguish between the male and female parts and their functions. Mentioning the hermaphroditic nature and external fertilization via cocoons is crucial.

 

Question 5. Give an account of locomotion of earthworm?
Answer: Earthworms move by crawling, using a combination of their body muscles, setae (bristles), and buccal chamber. Their body wall has two main layers of muscles: an outer circular muscle layer and an inner longitudinal muscle layer, which lie below the epidermis. When the circular muscles contract, the body becomes long and narrow. When the longitudinal muscles contract, the body shortens and broadens. These alternate waves of muscle contractions allow the earthworm to move forward. The chitinous setae act as anchors, gripping the soil and providing leverage. The buccal chamber also helps by anchoring the anterior end. This combination of muscle action and bristle support enables efficient movement through the soil.
A diagram illustrating locomotion would show:
• The anterior (front) end.
• Bristles (setae) extended and retracted.
• Muscle contraction and extension across segments, illustrating wave-like movement.
In simple words: Earthworms move by making their body long and thin, then short and fat, using their muscles. Small bristles on their body help them grip the ground and push forward.

🎯 Exam Tip: Focus on the coordinated action of circular and longitudinal muscles and the anchoring role of setae for a complete explanation of locomotion.

 

Question 6. Describe the morphological features of cockroach?
Answer: Cockroaches have a bilaterally symmetrical body, meaning it can be divided into two equal halves. Their body is segmented and is clearly divided into three main regions: head, thorax, and abdomen. The entire body is covered by a hard, chitinous exoskeleton. Each segment is covered by hardened plates called sclerites.
• **Head:** The head is small, triangular, and points downwards (hypognathous). It has a pair of large, kidney-shaped compound eyes, each made of about 2000 simple eyes called ommatidia, which give them mosaic vision. The mouth parts are designed for biting and chewing.
• **Thorax:** The thorax consists of three segments: prothorax, mesothorax, and metathorax. Each thoracic segment bears a pair of walking legs. Because they have three pairs of legs, they are called hexapods. Each leg has five segments: coxa, trochanter, femur, tibia, and tarsus. Cockroaches also have two pairs of wings. The first pair, called tegmina or elytra, arises from the mesothorax and covers the hind wings when at rest. The second pair of wings arises from the metathorax and is used for flight.
• **Abdomen:** The abdomen has 10 segments. The sclerites on the dorsal side are tergites, those on the ventral side are sternites, and those on the lateral sides are pleurites.
A diagram showing the morphological features would include:
• Head with filiform antennae and compound eyes.
• Thorax divided into prothorax, mesothorax, and metathorax.
• Tegmina (forewings) and hind wings.
• Three pairs of legs.
• Abdomen with segments.
• Anal cerci (at the posterior end of the abdomen).
In simple words: A cockroach has a segmented body with a triangular head, a thorax with three pairs of legs and two pairs of wings, and an abdomen with ten segments. Its body is covered by a hard outer shell.

🎯 Exam Tip: Clearly mention the three body divisions (head, thorax, abdomen) and key features of each, especially the compound eyes, wings, and leg structure.

 

Question 7. Draw the diagram of mouth parts of cockroach ?
Answer: The diagram of a cockroach's mouthparts illustrates the complex structures used for biting and chewing. It would typically show:
• **Labrum:** The upper lip, covering the front.
• **Mandibles:** A pair of strong, toothed jaws for crushing food, with grinding and incising regions.
• **Maxillae:** A pair of structures that help manipulate food and push it into the mouth.
• **Labium:** The lower lip, which helps hold food.
• **Hypopharynx (tongue):** A small, tongue-like structure.
These parts work together to process food.
In simple words: Draw the mouth of a cockroach, showing its upper lip, strong crushing jaws, other small parts to hold food, and its lower lip, all working together to eat.

🎯 Exam Tip: Ensure your diagram labels each mouthpart clearly and accurately, as the specific names are crucial for this question.

 

Question 8. Describe the structure of digestive system of cockroach with a diagram ?
Answer: The alimentary canal of a cockroach is divided into three main regions: the foregut, midgut, and hindgut. It is a straight tube that runs through the body.
**Foregut:** This includes the pre-oral cavity, mouth, pharynx, esophagus, and a large sac-like crop where food is stored. The crop is followed by the gizzard (proventriculus), which has chitinous teeth that help grind food particles. Salivary glands are also present near the foregut, secreting enzymes.
**Midgut:** This is a short, narrow tube. At the junction of the gizzard and midgut, eight finger-like, blind tubular processes called hepatic caecae (or enteric caecae) are present. These secrete digestive enzymes. At the junction of the midgut and hindgut, there are 100-150 yellow-colored Malpighian tubules, which are excretory organs that remove nitrogenous wastes from the hemolymph (insect blood).
**Hindgut:** This region is broader than the midgut and is divided into the ileum, colon, and rectum. The rectum opens to the outside through the anus.
A diagram of the digestive system would label:
• Salivary gland
• Crop
• Gizzard
• Hepatic caeca
• Midgut
• Malpighian tubules
• Colon
• Rectum (implied at the end of colon)
In simple words: A cockroach's digestive system is a tube with three parts. The front part stores and grinds food, the middle part has glands for digestion and tiny tubes for waste removal, and the back part absorbs water and releases waste.

🎯 Exam Tip: When describing the digestive system, link each section (foregut, midgut, hindgut) to its specific function and associated structures like hepatic caecae and Malpighian tubules.

 

Question 9. Describe the structure of circulatory system of cockroach ?
Answer: Cockroaches have an open circulatory system, which means their blood, called hemolymph, flows freely in body cavities rather than being confined to vessels. The body cavity is filled with this hemolymph. The heart is a long, muscular tube that runs along the middle of the back (mid-dorsally) beneath the thorax. It is elongated and has 13 chambers. Each chamber has small openings called ostia on its sides. Blood from the body sinuses enters the heart through these ostia and is then pumped forward into other sinuses. Along the sides of the heart, there are triangular muscles called alary muscles, which help in blood circulation. At the base of each antenna, there's also a pulsatile vesicle that helps pump blood. This system effectively distributes nutrients and collects waste without a complex network of arteries and veins.
A diagram showing the circulatory system would include:
• Chambers of the heart (13 chambers)
• Alary muscles (triangular muscles)
• Ostia (side openings into the heart chambers)
• The dorsal vessel (the heart tube itself)
• The general flow of hemolymph within the body cavity.
In simple words: Cockroaches have an open blood system, so their blood flows freely around organs. Their heart is a long tube with 13 chambers that pump the blood, helped by side muscles and a special pump near the antennae.

🎯 Exam Tip: Emphasize "open circulatory system" and the key role of the 13-chambered heart with ostia, as these are defining features.

 

Question 10. Give an account of excretory system of cockroach?
Answer: The primary excretory organs of the cockroach are the Malpighian tubules. These tubules are responsible for removing nitrogenous wastes from the body, primarily in the form of uric acid, making the cockroach uricotelic. This means they excrete solid or semi-solid uric acid, which helps conserve water. In addition to the Malpighian tubules, other structures like the fat body, nephrocytes, cuticle, and ureacose glands also play a role in excretion. The Malpighian tubules are attached at the junction between the midgut and hindgut, numbering about 100-150 tubules, grouped into 6-9 bundles. Each tubule is lined with glandular and ciliated cells. These cells absorb water, salts, and nitrogenous wastes from the hemolymph. The glandular cells of the Malpighian tubules are particularly important for absorbing nitrogenous wastes. The cells then reabsorb water and inorganic salts, concentrating the uric acid. Through muscular contractions, the nitrogenous waste is pushed into the ileum of the hindgut. The remaining waste, which is solid uric acid, is then expelled with the fecal matter.
A diagram of the excretory system would show:
• Midgut
• Malpighian tubules (numerous, attached at midgut-hindgut junction)
• Ileum (part of hindgut)
• Anus (exit point)
In simple words: Cockroaches get rid of waste using tiny tubes called Malpighian tubules, which take nitrogen waste (like uric acid) from their blood and push it out with their droppings. Other parts like fat bodies also help with this.

🎯 Exam Tip: Remember to name Malpighian tubules as the primary excretory organs and explain "uricotelic" in relation to water conservation.

 

Question 11. Describe the structure of the male reproductive system of a cockroach.
Answer: The male reproductive system of a cockroach includes several parts: a pair of testes, vasa deferentia, an ejaculatory duct, an utricular gland, a phallic gland, and external genitalia. The testes, which are three-lobed, are found in the 4th to 6th abdominal segments. From each testis, the vas deferens opens into the male gonopore, located on the ventral side of the anus. The mushroom-shaped gland is a large reproductive gland that opens into the front part of the ejaculatory duct. Sperms are stored in seminal vesicles as bundles called spermatophores. Small chitinous structures called phallomeres or gonopophyses surround the male genital opening, helping during copulation. This system ensures the transfer of genetic material for reproduction.
In simple words: The male cockroach has several organs for reproduction, including testes that make sperm, and glands that help store and transfer the sperm. These parts work together to allow the cockroach to mate.

🎯 Exam Tip: Remember the location of the testes (4th-6th segments) and the role of phallomeres in copulation for full marks.

 

Question 12. Describe the structure of the female reproductive system of a cockroach.
Answer: The female reproductive system of a cockroach includes a pair of ovaries, a vagina, a genital pouch, collateral glands, spermathecae, and external genitalia. The ovaries are situated in the 2nd to 6th abdominal segments. Each ovary is made up of eight ovarian tubules, where eggs develop. The oviducts from each ovary join to form a common oviduct, known as the vagina, which opens into the genital chamber. A pair of spermathecae are present in the 6th segment and also open into the genital pouch. During mating, eggs descend into the genital chamber and are fertilized by sperm. The collateral glands secrete a hard case called the ootheca around the eggs. This ootheca is then dropped into a crack or crevice, providing a safe place for the nymphs to develop and hatch.
In simple words: The female cockroach has ovaries that produce eggs and a system to fertilize them and then protect them in a strong egg case called an ootheca. This egg case keeps the baby cockroaches safe until they hatch.

🎯 Exam Tip: Focus on the number of ovarian tubules (eight), the location of the spermathecae (6th segment), and the role of the ootheca in protecting the eggs.

 

Question 13. Describe the morphological features of a frog.
Answer: The frog has a streamlined body shape, which helps it swim well. Its body is divided into two main parts: the head and the trunk. The head is triangular with a pointed snout and features a pair of external nostrils and eyes. These eyes have an unmovable upper eyelid and a movable lower eyelid for protection. A nictitating membrane also covers and protects the eye when the frog is underwater. Behind the eyes, there is a pair of eardrums (tympanum), but frogs do not have an external ear, neck, or tail. The trunk part of the frog has both forelimbs and hindlimbs. The hindlimbs are longer than the forelimbs, which helps the frog jump. The forelimbs help to support the body's weight. Each hindlimb has five webbed toes and one small extra toe, known as the sixth toe, useful for swimming and pushing off surfaces. Between the hindlimbs, at the back of the body, is the cloacal aperture.
In simple words: A frog has a smooth body, a triangular head with eyes, nostrils, and eardrums, but no neck or tail. Its body has front and back legs; the long back legs help it jump and swim, using webbed feet.

🎯 Exam Tip: Mention the streamlined body, absence of neck/tail, presence of nictitating membrane, and the adaptation of hindlimbs for jumping and swimming.

 

Question 14. Describe the digestive system of a frog.
Answer: The digestive system of a frog starts from the mouth and extends to the cloaca. The alimentary canal includes the buccal cavity, pharynx, esophagus, stomach, intestine, and rectum. The wide mouth opens into the buccal cavity, which has a large, muscular, sticky tongue. This tongue is attached at the front and free at the back, with a forked free edge, which is good for catching insects. Small maxillary teeth and vomerine teeth are found on the inner region of the upper jaw, while the lower jaw has no teeth. The mouth leads to the pharynx, then the esophagus, which opens into the stomach. The stomach connects to the intestine, which then leads to the rectum and finally opens into the cloaca. Organs like the liver and pancreas are also part of this system, producing digestive juices to break down food. This setup allows the frog to efficiently digest its carnivorous diet.
In simple words: A frog's digestive system starts at its wide mouth, goes through a short food pipe, into a stomach, and then through intestines to the cloaca. It uses a sticky tongue to catch food and has teeth in its upper jaw, with the liver and pancreas helping in digestion.

🎯 Exam Tip: Highlight the sticky, forked tongue, the absence of lower jaw teeth, and the pathway of food from mouth to cloaca, including the accessory organs.

 

Question 15. Describe the structure of the heart of a frog.
Answer: The heart of a frog has three chambers: two atria (auricles) and one ventricle. It is protected by a covering called the pericardium. On the dorsal side of the heart, there is a triangular chamber known as the sinus venosus. The truncus arteriosus, a thick-walled structure, is placed diagonally on the ventral surface of the heart. It splits into the right and left aortic trunks, which further divide into carotid systemic and pulmocutaneous arteries. These arteries supply blood to the posterior parts of the body, lungs, and skin. The sinus venosus receives deoxygenated blood from the pre and post venacava and delivers it to the right atrium. The left atrium receives oxygenated blood from the pulmonary vein. The three-chambered heart means that some mixing of oxygenated and deoxygenated blood occurs in the ventricle, making it less efficient than a four-chambered heart but sufficient for an amphibian.
In simple words: A frog's heart has three parts: two top chambers and one bottom chamber. It also has a sinus venosus that collects bad blood and a truncus arteriosus that sends good and mixed blood out. This design helps the frog live both on land and in water.

🎯 Exam Tip: When describing the frog's heart, clearly state the number of chambers and how blood flows through them, highlighting the mixing of blood as a key characteristic.

 

Question 16. Describe the structure of the respiratory system of a frog.
Answer: Frogs breathe in two main ways, depending on whether they are on land or in water. When in water, a frog uses its skin as an aquatic respiratory organ, a process called cutaneous respiration. Dissolved oxygen from the water passes through the skin into the frog's blood through diffusion. On land, the frog uses its buccal cavity, skin, and lungs for respiration. For buccal respiration on land, the frog's mouth stays closed, but its nostrils remain open. The floor of the buccal cavity moves up and down, drawing air into and pushing it out of the buccal cavity through the nostrils. Respiration using the lungs is called pulmonary respiration. The lungs are a pair of long, pink, sac-like structures located in the upper part of the trunk (thorax). Air enters through the nostrils, goes into the buccal cavity, and then to the lungs. During the periods of inactivity, most gaseous exchange happens through the skin. This dual respiratory system allows frogs to adapt to different environments.
In simple words: Frogs breathe using their skin in water. On land, they use their skin, mouth (buccal cavity), and lungs. Air moves in and out of the mouth cavity, and lungs are pink sacs for breathing.

🎯 Exam Tip: Clearly differentiate between cutaneous (skin) respiration in water and pulmonary (lung) and buccal respiration on land, explaining how each works.

 

Question 17. Describe the structure of the nervous system of a frog.
Answer: The nervous system of a frog is divided into three main parts: the central nervous system (CNS), the peripheral nervous system, and the autonomous nervous system. The CNS consists of the brain and spinal cord. The brain is covered by protective membranes called pia mater and dura mater. It is divided into the forebrain, midbrain, and hindbrain. The forebrain includes a pair of olfactory lobes, a cerebral hemisphere, and a diencephalon, which contains a small cavity called the olfactory ventricle. The midbrain has two large optic lobes and optic ventricles. The hindbrain is made up of the cerebellum and the medulla oblongata, which continues as the spinal cord after passing through the foramen magnum. The peripheral nervous system has 10 pairs of cranial nerves and 10 pairs of spinal nerves. The autonomous nervous system includes sympathetic and parasympathetic nervous systems, which control involuntary actions. This complex system allows the frog to sense its environment, process information, and respond accordingly.
In simple words: A frog's nervous system has a brain and spinal cord (CNS), nerves that go to different body parts (PNS), and nerves that control automatic functions (ANS). The brain has three parts: forebrain, midbrain, and hindbrain, each for different senses and actions.

🎯 Exam Tip: Listing the three main divisions (CNS, PNS, ANS) and then detailing the three parts of the brain (forebrain, midbrain, hindbrain) along with their key components is crucial.

 

Question 18. Draw the diagram of the buccal cavity of a frog and name the parts.
Answer: The buccal cavity of a frog is where digestion begins. It is a wide space that contains several important features for feeding and breathing. The diagram below shows the key parts:

In simple words: The diagram shows the inside of a frog's mouth. You can see its tongue, which is good for catching food, and tiny teeth in its upper jaw. It also has openings for breathing and hearing, like nostrils and Eustachian tubes.

🎯 Exam Tip: When drawing, ensure all key parts like the tongue, maxillary teeth, vomerine teeth, internal nostrils, glottis, and Eustachian tube openings are clearly labeled.

 

Question 19. Describe the locomotion of an earthworm.
Answer: Earthworms move by crawling, using their body muscles and special bristles called setae. Their body wall has two layers of muscles: an outer circular layer and an inner longitudinal layer, both located beneath the epidermis. When the circular muscles contract, the earthworm's body becomes long and thin. When the longitudinal muscles contract, the body becomes short and broad. The earthworm moves by making these muscles contract and relax in alternating waves along its body. The setae, which are chitinous bristles found in rings on most segments (except the first, last, and clitellum), help the worm grip the ground. These bristles act as anchors, preventing slippage and providing leverage as the worm pushes itself forward or pulls itself along. This wave-like muscle action, combined with the anchoring by setae, allows the earthworm to move effectively through the soil, a process vital for its survival and for enriching the soil.
In simple words: Earthworms move by stretching and shortening their bodies using muscles. Small hair-like bristles called setae help them grip the ground and push themselves forward.

🎯 Exam Tip: Explain the role of both circular and longitudinal muscles, and how the setae provide grip and leverage for movement.

 

Question 20. Tabulate the morphological differences between Lampito mauritii and Metaphire posthuma.
Answer: Here is a table comparing the physical characteristics of Lampito mauritii and Metaphire posthuma:

In simple words: Lampito mauritii and Metaphire posthuma are two types of earthworms with different body sizes, colors, and numbers of body segments. They also differ in where their clitellum, genital pores, and special digestive parts (intestinal caeca) are located.

🎯 Exam Tip: When tabulating differences, ensure all key distinguishing features are included and accurately represented for each organism.

 

Question 21. Tabulate anatomical differences between Lampito mauritii and Metaphire posthuma.
Answer: Here is a table outlining the anatomical differences between Lampito mauritii and Metaphire posthuma:

In simple words: These two types of earthworms have differences in where their reproductive openings (spermathecal) are located, and how their internal digestive parts like the pharynx, esophagus, and gizzard are positioned along their body segments. Their circulatory and excretory systems also show different segment distributions.

🎯 Exam Tip: For anatomical comparisons, remember the specific segment numbers where different organs like spermathecae, gizzard, and various nephridia are found.

 

Question 22. Differentiate between a male cockroach and a female cockroach.
Answer: Here is a table comparing the differences between male and female cockroaches:

In simple words: Male and female cockroaches look different in several ways, like the shape of their abdomen, the number of visible segments, and whether they have anal styles or a brood pouch. Their wings and antennae can also vary in length.

🎯 Exam Tip: Focus on easily observable external features like anal styles and wing length, as well as the number of visible abdominal segments, to differentiate effectively.

 

Question 23. Draw the life cycle of Lampito mauritii.
Answer: The life cycle of Lampito mauritii involves several stages, starting with mating, leading to cocoon formation, and eventually hatching into juveniles that grow into reproductive adults. The full cycle typically takes about 60 days. Mating is the first step, followed by the formation of a cocoon where eggs develop, which takes around 10 days. The eggs hatch into juvenile earthworms. These juveniles then undergo two growth phases. Growth phase I lasts about 15 days, and growth phase II takes about 17 days. During these phases, the earthworm develops. After these growth phases, the earthworm reaches the non-clitellate stage, where it doesn't have a clitellum. Finally, it reaches the reproductive period, becoming a clitellate adult, capable of mating and continuing the cycle. This entire process demonstrates the growth and development of the earthworm, playing a crucial role in soil health.

about 10 days Incubation
about 15 days Growth phase I
about 15 days Growth phase II
about 17 days about 60 days Mating
In simple words: The life cycle of an earthworm, Lampito mauritii, starts with mating, then a cocoon is laid which holds the eggs. These eggs hatch into young earthworms, which grow through stages until they become adults that can mate and lay cocoons themselves.

🎯 Exam Tip: When drawing a life cycle, ensure a clear sequence of stages and label each stage with its approximate duration if provided. Use arrows to show the flow.

 

Question 24. Differentiate between a frog and a toad.
Answer: Here is a table comparing the differences between a frog and a toad:

In simple words: Frogs and toads are both amphibians, but they have key differences. Frogs typically have smooth, moist skin, longer legs for jumping, and lay eggs in clusters. Toads usually have dry, bumpy skin, shorter legs, and lay eggs in long strings.

🎯 Exam Tip: Focus on observable features like skin texture, leg length, and how eggs are laid, as these are common distinguishing characteristics between frogs and toads.