Samacheer Kalvi Class 9 Science Solutions Chapter 17 Animal Kingdom

Samacheer Kalvi 9th Science Solutions Chapter 17 Animal Kingdom

9th Science Guide Animal Kingdom Text Book Back Questions And Answers

I. Choose The Correct Answer:

 

Question 1. Find the group having only marine members.
(a) Mollusca
(b) Coelenterata
(c) Echinodermata
(d) Porifera
Answer: (c) Echinodermata
In simple words: Echinodermata is a group of sea animals like starfish. All animals in this group live only in the ocean, nowhere else.

🎯 Exam Tip: Remember specific phyla characteristics; "only marine" is a key identifier for Echinodermata, setting it apart from other groups.

 

Question 2. Mesoglea is present in
(a) Porifera
(b) Coelenterata
(c) Annelida
(d) Arthropoda
Answer: (b) Coelenterata
In simple words: Mesoglea is a jelly-like layer found between the two main body layers of animals like jellyfish, which belong to the Coelenterata group. This layer gives them support and shape.

🎯 Exam Tip: Associate unique structural components like Mesoglea with the specific animal phyla they characterize to remember them easily.

 

Question 3. Which one of the following pairs is not a poikilothermic animal
(a) Fishes and Amphibians
(b) Amphibians and Aves
(c) Aves and Mammals
(d) Reptiles and Mammals
Answer: (c) Aves and Mammals
In simple words: Poikilothermic animals, like fish and amphibians, have body temperatures that change with their surroundings. Aves (birds) and Mammals (like humans) keep their body temperature stable, so they are not poikilothermic.

🎯 Exam Tip: Clearly distinguish between poikilothermic (cold-blooded, varying body temperature) and homeothermic (warm-blooded, stable body temperature) animals.

 

Question 4. Identify the animal having four chambered heart.
(a) Lizard
(b) Snake
(c) Crocodile
(d) Calotes
Answer: (c) Crocodile
In simple words: Most reptiles have a three-chambered heart, but crocodiles are special because they have a four-chambered heart, just like birds and mammals. This helps them pump blood more effectively.

🎯 Exam Tip: Note the unique exception of crocodiles within the reptile group regarding their heart structure; this is a common trick question.

 

Question 5. The animal without skull is
(a) Acrania
(b) Acephalia
(c) Apteria
(d) Acoelomate
Answer: (a) Acrania
In simple words: Animals that do not have a skull to protect their brain are called Acrania. This group includes simpler chordates that lack a distinct head.

🎯 Exam Tip: Remember that "cranium" refers to the skull, so "Acrania" literally means "without a skull".

 

Question 6. Hermaphrodite organisms are
(a) Hydra, Tape worm, Earthworm, Amphioxus
(b) Hydra, Tape worm, Earthworm, Ascidian
(c) Hydra, Tape worm, Earthworm, Balanoglossus
(d) Hydra, Tape worm, Ascaris, Earthworm
Answer: (b) Hydra, Tape worm, Earthworm, Ascidian
In simple words: Hermaphrodite organisms are those that have both male and female reproductive organs in the same individual. This allows them to produce both eggs and sperm.

🎯 Exam Tip: Memorize examples of hermaphrodite animals from different phyla, as they often appear in multiple-choice questions.

 

Question 7. Poikilothermic organisms are
(a) Fish, Frog, Lizard, Man
(b) Fish, Frog, Lizard, Cow
(c) Fish, Frog, Lizard, Snake
(d) Fish, Frog, Lizard, Crow
Answer: (c) Fish, Frog, Lizard, Snake
In simple words: Poikilothermic animals are often called "cold-blooded" because their body temperature changes with the temperature of their surroundings. Fish, frogs, lizards, and snakes are all examples of such animals.

🎯 Exam Tip: Understand that poikilothermic animals include fish, amphibians, and reptiles, while birds and mammals are homeothermic.

 

Question 8. Air sacs and Pneumatic bones are seen in
(a) fish
(b) frog
(c) bird
(d) bat
Answer: (c) Bird
In simple words: Birds have special features like air sacs connected to their lungs and hollow bones filled with air (pneumatic bones). These adaptations help them to be lightweight and efficient for flying.

🎯 Exam Tip: Connect specialized structures like air sacs and pneumatic bones directly to the function of flight, a key adaptation for birds.

 

Question 9. Excretory organ of tape worm is
(a) flame cells
(b) nephridia
(c) body surface
(d) solenocytes
Answer: (a) Flame cells
In simple words: Tapeworms, which are flatworms, use special cells called flame cells to remove waste products from their bodies. These cells have cilia that beat like a flame.

🎯 Exam Tip: Learn the specific excretory organs for different invertebrate groups, as they are distinct and important for classification.

 

Question 10. Water vascular system is found in
(a) Hydra
(b) Earth worm
(c) Star fish
(d) Ascaris
Answer: (c) Starfish
In simple words: Starfish and other echinoderms have a unique water vascular system, which uses water pressure to help them move, catch food, and breathe. It is a defining feature of this group.

🎯 Exam Tip: The water vascular system is a characteristic feature of echinoderms, essential for their locomotion and feeding.

II. Fill In The Blanks:

 

Question 1. The skeletal framework of Porifera is ..........................
Answer: spicules
In simple words: Sponges (Porifera) have a skeleton made of tiny, sharp structures called spicules, which give them support. These spicules can be made of calcium carbonate or silica.

🎯 Exam Tip: Remember that spicules are the main structural components providing support to sponges.

 

Question 2. Ctenidia are respiratory organs in ..........................
Answer: phylum mollusca
In simple words: Ctenidia are feather-like gills found in molluscs, like snails and clams, which help them breathe underwater. They filter oxygen from the water as it passes over them.

🎯 Exam Tip: Associate ctenidia specifically with molluscs as their primary respiratory organs.

 

Question 3. Skates are .......................... fishes.
Answer: cartilaginous
In simple words: Skates are a type of fish that have skeletons made of cartilage instead of bone, similar to sharks. This makes their skeletons flexible and lighter.

🎯 Exam Tip: Differentiate between cartilaginous fish (like skates and sharks) and bony fish, noting their skeletal differences.

 

Question 4. The larvae of an amphibian is .......................... bilaterally symmetrical
Answer: tadpole
In simple words: Amphibians, like frogs, start their lives as larvae called tadpoles, which are bilaterally symmetrical. Tadpoles live in water and breathe through gills before changing into adults.

🎯 Exam Tip: Know the larval stages of amphibians (tadpole) and their characteristics, as metamorphosis is a key concept.

 

Question 5. .......................... are jawless vertebrates.
Answer: Cyclostomes
In simple words: Cyclostomes are a group of fish-like vertebrates that do not have jaws, such as lampreys and hagfish. They are primitive vertebrates that feed by sucking.

🎯 Exam Tip: Remember that cyclostomes are unique among vertebrates for their lack of jaws.

 

Question 6. .......................... is the unique characteristic feature of mammal.
Answer: Placenta
In simple words: The placenta is a special organ that grows in most female mammals during pregnancy, connecting the mother to the baby. It provides nutrients and oxygen to the developing fetus.

🎯 Exam Tip: The presence of a placenta is a key distinguishing feature for most mammals, indicating viviparous reproduction.

 

Question 7. Spiny anteater is an example for .......................... mammal.
Answer: egg-laying
In simple words: The spiny anteater (echidna) is a special type of mammal that lays eggs instead of giving birth to live young. These are called monotremes, a small group of mammals.

🎯 Exam Tip: Remember the exceptions to general mammalian characteristics, such as egg-laying mammals (monotremes like echidna and platypus).

III. State Whether True Or False. If False Write The Correct Statement:

 

Question 1. Canal system is seen in coelenterates.
Answer: False.
Correct statement: Canal system is seen in porifera
In simple words: The canal system, which helps in water circulation, is a unique feature of sponges (Porifera), not coelenterates. Coelenterates have a gastrovascular cavity.

🎯 Exam Tip: Clearly link the canal system to Porifera; it's a defining feature for sponges.

 

Question 2. Hermaphrodite animals have both male and female sex organs.
Answer: True.
In simple words: An animal is called a hermaphrodite if it has both reproductive parts, male and female, in the same body. This allows them to produce both types of gametes.

🎯 Exam Tip: Understand the definition of hermaphroditism; it's common in many invertebrate species.

 

Question 3. Trachea are the respiratory organ of Annelida.
Answer: False.
Correct statement: Trachea are the respiratory organ of Arthropoda.
In simple words: Trachea are breathing tubes found in insects and other arthropods, helping them take in air directly to their tissues. Annelids, like earthworms, breathe through their moist skin.

🎯 Exam Tip: Correctly identify the respiratory organs for each phylum; trachea are characteristic of terrestrial arthropods.

 

Question 4. Bipinnaria is the larva of Mollusca.
Answer: False.
Correct statement: Bipinnaria is the larva of star fish.
In simple words: The bipinnaria is a type of larva that develops into a starfish, which belongs to the Echinodermata phylum. Molluscs have different larval forms, such as trochophore and veliger.

🎯 Exam Tip: Be precise about larval forms and the phyla they belong to, as this is a common point of confusion.

 

Question 5. Balanoglossus is a ciliary feeder.
Answer: True.
In simple words: Balanoglossus uses tiny hair-like structures called cilia to create water currents that bring food particles into its mouth. This method of eating is known as ciliary feeding.

🎯 Exam Tip: Understand the feeding mechanisms of different organisms, especially specialized ones like ciliary feeding.

 

Question 6. Fishes have two chambered heart.
Answer: True.
In simple words: Fish have a two-chambered heart with one atrium and one ventricle, which pumps blood through their gills and then to the rest of the body in a single circulation. This is a characteristic feature of most fish.

🎯 Exam Tip: Know the number of heart chambers for different vertebrate classes; fish have a simple two-chambered heart.

 

Question 7. Skin of reptilians are smooth and moist.
Answer: False.
Correct statement: Skin of cyclostomata are smooth and moist.
In simple words: Reptiles have dry, scaly skin that helps them prevent water loss and adapt to land environments. Cyclostomes, like lampreys, have smooth and moist skin.

🎯 Exam Tip: Recall the adaptations of reptile skin (scales, dryness) which are crucial for their terrestrial lifestyle.

 

Question 8. Wings of birds are the modified forelimbs.
Answer: True
In simple words: The front limbs of birds have changed over time into wings, which allow them to fly. This is a major adaptation for aerial life.

🎯 Exam Tip: Understand the evolutionary adaptation of bird forelimbs into wings for flight.

 

Question 9. Female mammals have mammary glands.
Answer: True.
In simple words: Female mammals have mammary glands, which are special glands that produce milk to feed their young ones. This is a defining characteristic of mammals.

🎯 Exam Tip: Mammary glands are a key feature that gives mammals their name ("mamma" meaning breast).

IV. Match The Following:

 

Question 1.

Answer: A – iv, B – iii, C – ii, D – i
In simple words: This match connects each animal phylum with a correct example. Coelenterata includes Hydra, Platyhelminthes includes Tapeworm, Echinodermata includes Starfish, and Mollusca includes Snail.

🎯 Exam Tip: Create flashcards or diagrams to help remember key examples for each phylum, as matching questions frequently test this knowledge.

V. Answer Very Briefly:

 

Question 1. Define taxonomy.
Answer: Taxonomy is the scientific study of how living things are classified, including their basic principles, procedures, and rules. It helps us organize and understand the diversity of life on Earth.
In simple words: Taxonomy is the study of classifying living things into groups, following a set of rules.

🎯 Exam Tip: When defining scientific terms, ensure you include key concepts like "classification," "principles," and "rules" for a complete answer.

 

Question 2. What is nematocyst?
Answer: Nematocysts are special stinging cells found on the tentacles of organisms belonging to the phylum Coelenterata, like jellyfish and sea anemones. These cells are used for capturing prey and for defense.
In simple words: Nematocysts are stinging cells on coelenterate tentacles, used for catching food and for protection.

🎯 Exam Tip: Remember that nematocysts are a unique and defining feature of the phylum Cnidaria (Coelenterata), indicating their predatory nature.

 

Question 3. Why coelenterates are called diploblastic animals?
Answer: Coelenterates are called diploblastic animals because their body wall is made of only two main layers: an outer ectoderm and an inner endoderm. These two layers are separated by a non-cellular jelly-like substance called mesoglea.
In simple words: Coelenterates are diploblastic because their bodies have only two cell layers, an outer and an inner, with a jelly layer in between.

🎯 Exam Tip: Distinguish between diploblastic (two germ layers) and triploblastic (three germ layers) animals, noting that coelenterates are the former.

 

Question 4. List the respiratory organs of amphibians.
Answer: Amphibians can breathe in several ways, using different organs depending on their life stage and environment. Their respiratory organs include gills (in larvae like tadpoles), skin (cutaneous respiration), buccopharynx (lining of the mouth and throat), and lungs (in adult amphibians).
In simple words: Amphibians breathe using gills when young, and skin, buccopharynx, and lungs as adults.

🎯 Exam Tip: Highlight the multiple respiratory organs of amphibians, reflecting their dual adaptation to aquatic and terrestrial environments.

 

Question 5. How does locomotion take place in starfish?
Answer: Locomotion in starfish takes place with the help of their tube feet, which are part of their water vascular system. Water pressure helps to extend and retract these tube feet, allowing the starfish to move slowly along surfaces. They use the suckers at the ends of the tube feet to grip surfaces.
In simple words: Starfish move using their tube feet, which work with water pressure.

🎯 Exam Tip: Focus on the tube feet and the water vascular system as the primary mechanisms for locomotion in starfish.

 

Question 6. Are jellyfish and starfish similar to fishes? If no justify the answer.
Answer: No, jellyfish and starfish are not similar to fishes. Here's why:

• Jellyfish is a coelenterate, and its body is made of calcium carbonate.
• Starfish is an echinoderm, and its body is also made of calcium carbonate.
• Catfish, on the other hand, is a true fish species, belonging to the Chordata phylum.
• Jellyfish and starfish are invertebrates, meaning they do not have a backbone. True fish are vertebrates.

They have different body structures, feeding habits, and classification groups. For example, jellyfish lack true organs.
In simple words: No, jellyfish and starfish are not fish. Jellyfish are coelenterates and starfish are echinoderms, and both are invertebrates. Fish are vertebrates with backbones and different body structures.

🎯 Exam Tip: Emphasize that "fish" refers to a specific group of vertebrates, and many marine animals are misnamed "fish" but belong to entirely different phyla.

 

Question 7. Why are frogs said to be amphibians?
Answer: Frogs are called amphibians because they have a dual adaptation, meaning they can live both on land and in water. They start their lives in water as tadpoles, breathing with gills, and then undergo metamorphosis to become adults that can live on land, breathing with lungs and skin. This ability to thrive in two different environments is characteristic of amphibians.
In simple words: Frogs are amphibians because they can live both in water and on land, changing their breathing organs as they grow.

🎯 Exam Tip: The key to defining amphibians is their dual habitat adaptation and the metamorphosis from an aquatic larval stage to a terrestrial adult stage.

VI. Answer Briefly:

 

Question 1. Give an account on phylum Annelida.
Answer: Annelida is a phylum of segmented worms, commonly known as ringed worms or segmented worms. Here are some key features:

• They are bilaterally symmetrical and triploblastic, meaning they have three germ layers. They are also the first true coelomate animals, with an organ-system grade of organization.
• Their body is externally divided into segments, called metameres, which are joined by ring-like structures called annuli. This segmentation allows for specialized functions.
• Their body is covered by a moist, thin cuticle, which aids in gas exchange.
• They use setae (bristles) and parapodia (fleshy, paired appendages) for movement.
• Sexes may be separate (dioecious) or united (hermaphrodites).

Examples include Nereis, Earthworm, and Leech.
In simple words: Annelids are segmented worms with a true body cavity. They have a moist skin, move with bristles, and can have separate or combined sexes. Earthworms are a common example.

🎯 Exam Tip: Focus on segmentation, coelom, and the presence of setae/parapodia as defining characteristics of Annelida.

 

Question 2. Differentiate between flatworms and roundworms?
Answer: Here are the differences between flatworms (Phylum Platyhelminthes) and roundworms (Phylum Aschelminthes):

In simple words: Flatworms are usually parasites with simple bodies and no body cavity, while roundworms can be free-living or parasitic, have a fake body cavity, and a straight digestive tube.

🎯 Exam Tip: Focus on key differences like body cavity type (acoelomate vs. pseudocoelomate) and digestive system structure for clear differentiation.

 

Question 3. Outline the flow charts of Phylum Chordata.
Answer: The classification of Phylum Chordata can be outlined as follows:
Phylum Chordata is divided into three main subphyla:

• Subphylum Urochordata: These are invertebrates, also known as tunicates, e.g., Ascidian.
• Subphylum Cephalochordata: These are small, fish-like marine chordates, e.g., Amphioxus.
• Subphylum Vertebrata: These are chordates with a vertebral column (backbone).

Vertebrates are further divided into:

• Vertebrates without Jaws (Agnatha): Represented by Class Cyclostomata, e.g., Lamprey, Hagfish.
• Vertebrates with Jaws (Gnathostomata): Further divided into different classes:
  
  • Class Pisces (Fish): e.g., Shark, Mullet.
  • Class Amphibia (Amphibians): e.g., Frog, Toad.
  • Class Reptilia (Reptiles): e.g., Lizard, Snake.
  • Class Aves (Birds): e.g., Pigeon, Ostrich.
  • Class Mammalia (Mammals): e.g., Rabbit, Man.

This hierarchical chart helps to understand the relationships and evolutionary progression within the chordate phylum.
In simple words: The Chordata phylum includes animals with a notochord. It is split into Urochordata, Cephalochordata, and Vertebrata. Vertebrates are further divided into jawless and jawed animals, with jawed animals including fish, amphibians, reptiles, birds, and mammals.

🎯 Exam Tip: Understanding the hierarchy and key examples for each subphylum and class within Chordata is crucial for detailed knowledge.

 

Question 4. List five characteristic features of fishes.
Answer: Here are five characteristic features of fishes:

• Fishes are poikilothermic, meaning their internal body temperature varies with the surrounding environment.
• Their body has a covering of scales, which provides protection.
• Body muscles are arranged into segments called myotomes, which aid in swimming.
• The body is typically differentiated into a head, trunk, and tail.
• Respiration is done by 5 to 7 pairs of gills, which are sometimes covered by an operculum or may be naked.

Fishes possess fins for movement and balance, which is another defining feature.
In simple words: Fish are cold-blooded, have scales, segmented muscles for swimming, a distinct head, trunk, and tail, and breathe using gills.

🎯 Exam Tip: When listing characteristics, aim for a clear and concise point for each feature, covering aspects like thermoregulation, body covering, and respiration.

 

Question 5. Comment on the aquatic and terrestrial habits of amphibians.
Answer: Amphibians exhibit dual adaptation, living both in aquatic and terrestrial environments. This is reflected in their life cycle and physiological features.
Aquatic habits of amphibians:

• The larva of amphibians, known as a tadpole, lives in water and breathes using gills.
• External fertilization usually occurs in frogs, with water serving as the medium for fertilization.
• Adult frogs often have webbed feet, which help them swim efficiently in water.
• Their skin remains moist and glandular, allowing for cutaneous respiration (breathing through the skin) when in water.

Terrestrial habits of amphibians:

• Adult amphibians typically live on land and breathe primarily through their lungs.
• The buccopharynx (mouth and throat lining) also assists in respiration on land.
• Their forelimbs are often short and adapted to help them hop or walk on land.

This unique life cycle, with distinct aquatic and terrestrial phases, defines amphibians.
In simple words: Amphibians live in both water and on land. Young ones (tadpoles) live in water and breathe with gills, while adults live on land and breathe with lungs and skin.

🎯 Exam Tip: Structure your answer by clearly separating aquatic and terrestrial adaptations, highlighting how each physiological feature supports life in its respective environment.

 

Question 6. How are the limbs of the birds adapted for avian life?
Answer: The limbs of birds are highly adapted for avian life, particularly for flight:
1. Birds have a streamlined, spindle-shaped body which helps reduce air resistance during flight. This body shape makes movement through the air easier.
2. Their forelimbs are uniquely modified into wings, which are essential for aerial locomotion. These wings generate lift and thrust.
3. The presence of air sacs within the bird's body makes the bird lightweight, aiding in flight and providing efficient respiration. These sacs extend into the bones.
4. The body is covered with feathers, which provide insulation, shape the wings for flight, and contribute to a smooth aerodynamic surface. The feathers are vital for flight control and protection.
In simple words: Birds have wings made from their front limbs for flying, a streamlined body, air sacs to keep them light, and feathers for flight and warmth.

🎯 Exam Tip: When discussing adaptations for flight, cover multiple aspects: body shape, limb modification, skeletal structure (pneumatic bones/air sacs), and body covering (feathers).

VII. Answer In Detail:

 

Question 1. Describe the characteristic features of different Prochordates.
Answer: Prochordates are a group of chordates that lack a true vertebral column. They are considered the forerunners of vertebrates and are classified into subphylum Urochordata and subphylum Cephalochordata, based on the nature and location of their notochord. Additionally, Phylum Hemichordata is often studied alongside prochordates due to some shared features.
Phylum Hemichordata:

• Hemichordates are marine organisms with soft, vermiform (worm-like), and unsegmented bodies.
• They exhibit bilateral symmetry and are coelomate animals, possessing both non-chordate and chordate features.
• A key feature is the presence of gill slits. However, they do not possess a true notochord.
• They are often ciliary feeders and mostly remain as tubicolous forms, e.g., Balanoglossus (also known as acorn worms).

Subphylum Urochordata:

• In Urochordates (e.g., Ascidian), the notochord is present only in the tail region of the free-living larval stage.
• Adults are sessile (fixed in one place) forms and often undergo degeneration, losing many larval features.
• Their body is covered with a tunic or test, which is a leathery covering.

Subphylum Cephalochordata:

• Cephalochordates are small, fish-like marine chordates that possess unpaired dorsal fins.
• A defining characteristic is that the notochord extends throughout the entire length of their body, from head to tail, and persists throughout their life.

An example is Amphioxus (also known as Lancelet). These subphyla illustrate the diversity and evolutionary steps within the broader Chordata group.
In simple words: Prochordates are simple chordates without a backbone, divided into Hemichordata (worm-like, gill slits, no true notochord), Urochordata (notochord only in larva's tail, sessile adults), and Cephalochordata (notochord runs through the whole body).

🎯 Exam Tip: For prochordates, clearly differentiate the location and persistence of the notochord across the subphyla, as this is their primary distinguishing feature.

 

Question 2. Give an account on phylum Arthropoda.
Answer: Phylum Arthropoda is the largest phylum in the animal kingdom, including insects, spiders, crabs, and more. Here are its characteristic features:

• Arthropods have jointed legs, which is a key defining characteristic, giving the phylum its name ("arthron" meaning joint, "podos" meaning foot).
• Their body is segmented, typically divided into a head, thorax, and abdomen.
• They possess a rigid exoskeleton made up of chitin, which provides protection and support but must be shed periodically through a process called moulting as the animal grows.
• The coelomic cavity (body cavity) is filled with a fluid called haemolymph, which acts as blood.
• They have an open circulatory system, meaning their blood (haemolymph) is not always enclosed in vessels but flows freely within the body cavity.
• Small arthropods absorb oxygen directly through their body surface, while larger aquatic species breathe through book gills.
• Terrestrial arthropods breathe through a system of tiny body tubes called tracheae, which deliver oxygen directly to tissues.
• Excretion occurs through specialized organs such as malpighian tubules (in insects) and green glands (in crustaceans like crabs and prawns).

Examples of arthropods include insects (butterflies, centipedes), arachnids (spiders, scorpions), and crustaceans (crabs, shrimps, millipedes).
In simple words: Arthropods are the largest animal group, known for jointed legs, segmented bodies, and a hard outer shell (exoskeleton) made of chitin. They have an open blood system and breathe using gills or tracheal tubes.

🎯 Exam Tip: When describing Arthropoda, highlight their vast diversity and common features like jointed appendages, exoskeleton, segmented body, and open circulatory system.

9th Science Guide Animal Kingdom Additional Important Questions and Answers

I. Choose the Correct Answer:

 

Question 1. Find the group having only marine members.
(a) Mollusca
(b) Coelenterata
(c) Echinodermata
(d) Porifera
Answer: (c) Echinodermata
In simple words: Echinoderms are a group of sea animals that live only in salty ocean water, like starfish and sea urchins. They cannot survive in fresh water.

🎯 Exam Tip: Remember specific examples for each phylum to easily identify unique characteristics like marine-only habitats.

 

Question 2. Which is not a feature of chordates?
(a) Green glands
(b) Sweat glands
(c) Sebaceous gland
(d) Mammary gland
Answer: (a) Green glands
In simple words: Green glands are a type of excretory organ found in some crustaceans, not in chordates. Chordates have different glands like sweat, sebaceous, and mammary glands.

🎯 Exam Tip: Focus on distinguishing features for each animal phylum, especially unique organs like glands.

 

Question 3. Choose the correct terms related to Hemichordate
(a) Vermiform, unsegmented, bilaterally symmetrical, ciliary feeders
(b) Vermiform, segmented, triploblastic, ciliary feeders
(c) Vermiform, unsegmented, diploblastic, ciliary feeders
(d) Vermiform, unsegmented, triploblastic, filter feeders
Answer: (a) Vermiform, unsegmented, bilaterally symmetrical, ciliary feeders
In simple words: Hemichordates are soft, worm-like creatures with unsegmented bodies and two symmetrical halves. They use small hair-like structures called cilia to filter feed.

🎯 Exam Tip: When describing phyla, recall key characteristics such as body shape, segmentation, symmetry, and feeding methods.

 

Question 4. The ................ can swim faster than a cheetah.
(a) Sail fish
(b) Catfish
(c) Jelly fish
(d) Sucker fish
Answer: (a) Sail fish
In simple words: The sailfish is known as one of the fastest fish in the ocean. It can swim at incredible speeds, much faster than a cheetah can run on land.

🎯 Exam Tip: General knowledge questions often test facts about unique animal abilities; remember superlative facts like "fastest" or "biggest."

 

Question 5. The biggest vertebrate animal is the ....................
(a) Blue whale
(b) Dolphin
(c) Elephant
(d) Rhinoceros
Answer: (a) Blue whale
In simple words: The blue whale is the largest animal on Earth, and it is also the largest vertebrate. It lives in the ocean and can grow to be very long and heavy.

🎯 Exam Tip: Learn facts about the largest, smallest, fastest, and most unique animals in different categories (vertebrates, invertebrates, mammals, etc.).

 

Question 6. Who introduced binomial nomenclature?
(a) Huxley
(b) Carolus Linnaeus
(c) Nicolaus Copernicus
(d) Charles Darwin
Answer: (b) Carolus Linnaeus
In simple words: Carolus Linnaeus was a scientist who created the system we use today to give every living thing a two-part scientific name. This system helps everyone around the world use the same name for each species.

🎯 Exam Tip: Key scientists and their contributions to biology, especially in classification and evolution, are common exam topics.

 

Question 7. What is the binomial name of tapeworm?
(a) Ascaris lumbricoides
(b) Taenia solium
(c) Lampito mauritii
(d) Hirudinaria granulosa
Answer: (b) Taenia solium
In simple words: The scientific name for the common human tapeworm is Taenia solium. This name helps scientists identify it uniquely across different languages and regions.

🎯 Exam Tip: Memorize the binomial names of commonly studied organisms, as they are often tested in biology exams.

 

Question 8. Which is the state bird of Tamil Nadu?
(a) Peacock
(b) Parrot
(c) Emerald dove
(d) Eagle
Answer: (c) Emerald dove
In simple words: The Emerald Dove is the official state bird of Tamil Nadu. It is a beautiful bird known for its green and bronze feathers.

🎯 Exam Tip: Be aware of the state symbols (birds, animals, trees, flowers) of different regions, as these can appear in general knowledge sections.

 

Question 9. .................... is an example of bony fish.
(a) Mullets
(b) Sharks
(c) Skates
(d) Hagfish
Answer: (a) Mullets
In simple words: Mullets are a type of fish that have a skeleton made of bone, unlike sharks and skates which have cartilage. They are often found in coastal waters.

🎯 Exam Tip: Differentiate between cartilaginous fish (Chondrichthyes) and bony fish (Osteichthyes) by remembering common examples of each.

 

Question 10. The notochord extends throughout the entire length of the body.
(a) Acorn worms
(b) Lamprey
(c) Ascidian
(d) Amphioxus
Answer: (d) Amphioxus
In simple words: Amphioxus is a small, fish-like animal where the notochord, a rod-like structure, runs from its head to its tail. This is a key feature of its body structure.

🎯 Exam Tip: Understand the characteristics of different subphyla of Chordata, specifically how the notochord is present and its extent.

 

Question 11. Animals which possess notochord are called as ....................
(a) invertebrates
(b) non-chordates
(c) chordates
(d) all the options
Answer: (c) chordates
In simple words: Any animal that has a notochord at some point in its life is called a chordate. This notochord acts like a backbone in early development.

🎯 Exam Tip: The presence of a notochord is the defining feature of the phylum Chordata, crucial for classification.

 

Question 12. What is the name of the bone which is filled with air?
(a) Flat bones
(b) Irregular bones
(c) Short bones
(d) Pneumatic bones
Answer: (d) Pneumatic bones
In simple words: Pneumatic bones are special bones that have air spaces inside them. This makes them lighter and is found in birds, helping them to fly easily.

🎯 Exam Tip: Link the term "pneumatic" to "air" or "lungs" to remember its meaning in biology, especially regarding bird anatomy.

 

Question 13. .................... is the unique characteristic feature of mammals.
(a) Placenta
(b) Egg
(c) Tail
(d) Ear
Answer: (a) Placenta
In simple words: The placenta is a special organ that grows inside the mother's womb to nourish the baby before it is born. This feature is unique to most mammals.

🎯 Exam Tip: Identify key distinguishing features for each animal class; for mammals, the placenta (in most) and mammary glands are vital.

 

Question 14. .................... have gill slits but do not have notochord.
(a) Phylum Hemichordata
(b) Phylum Echirodermata
(c) Phylum Mollusca
(d) Phylum Annelida
Answer: (a) Phylum Hemichordata
In simple words: Hemichordates are a group of marine animals that have gill slits, like chordates, but they do not develop a true notochord. This puts them in a unique position between invertebrates and chordates.

🎯 Exam Tip: Understand the transitional characteristics of Hemichordata, which share features with both non-chordates and chordates.

II. Fill In the Blanks:

 

1. The binomial name of our National Bird is ....................
Answer: pavocristatus
In simple words: The scientific name for India's national bird, the peacock, is Pavocristatus. This two-part name helps classify it in the animal kingdom.

🎯 Exam Tip: Knowing the scientific names of important national animals or plants is often tested in general knowledge or biology sections.

 

2. In mammals testis are enclosed by ....................
Answer: scrotal sacs
In simple words: In most mammals, the testes are held outside the main body cavity in a pouch called the scrotal sacs. This keeps them at a cooler temperature, which is important for sperm production.

🎯 Exam Tip: Remember the specific anatomical structures and their functions, especially those unique to mammalian reproduction.

 

3. In birds, the air sacs communicate with ....................
Answer: lungs
In simple words: Birds have air sacs that connect to their lungs. These air sacs help with breathing by pushing air through the lungs in a special way, allowing birds to get a lot of oxygen.

🎯 Exam Tip: Understand the unique respiratory system of birds, which includes air sacs for efficient oxygen exchange during flight.

 

4. The animals belonging to phylunm .................... are said to be soft-bodied.
Answer: mollusca
In simple words: Animals in the phylum Mollusca, like snails and octopuses, have soft bodies. Many of them have a hard shell to protect their soft bodies.

🎯 Exam Tip: Associate key characteristics, like "soft-bodied," with the correct animal phylum for accurate classification.

 

5. The name .................... means "thousand legs”.
Answer: millipede
In simple words: The word "millipede" literally means "thousand feet." These creatures are known for having many pairs of tiny legs along their long bodies.

🎯 Exam Tip: Learn common prefixes and suffixes in scientific terms to understand their meaning, such as "milli-" for thousand and "ped-" for foot.

 

6. The skeletal framework of phylum Porifera is made up of ....................
Answer: spicules
In simple words: Sponges, which are part of the phylum Porifera, have a skeleton made of tiny, sharp structures called spicules. These spicules give the sponge its shape and support.

🎯 Exam Tip: Recall the unique structural components of simpler organisms, like spicules in sponges, which are important for their support.

 

7. A true body cavity is located within ....................
Answer: mesoderm
In simple words: A true body cavity, or coelom, is found inside the middle germ layer, called the mesoderm, during an animal's development. This cavity separates the digestive tract from the body wall.

🎯 Exam Tip: Understand the three germ layers (ectoderm, mesoderm, endoderm) and how the coelom forms within the mesoderm in true coelomates.

 

8. .................... separates the digestive tract from the body wall.
Answer: Coelom
In simple words: The coelom is an empty space inside the body that separates the gut from the outer body wall. It provides room for organs to grow and move.

🎯 Exam Tip: Define the coelom accurately as the fluid-filled body cavity that offers space and cushioning for internal organs.

 

9. .................... formed during embryonic development.
Answer: Notochord
In simple words: The notochord is a flexible, rod-like structure that forms early in the development of chordate embryos. It provides skeletal support.

🎯 Exam Tip: Recognize the notochord as a key feature of chordates, appearing during their embryonic stage and providing a basic skeletal axis.

 

10. .................... is the largest phylum of the animal kingdom.
Answer: Arthropoda
In simple words: Arthropoda is the biggest group of animals, including insects, spiders, and crabs. They have jointed legs and a hard outer shell.

🎯 Exam Tip: Remember that Arthropoda is the most diverse and numerous phylum, covering a vast range of species.

 

11. .................... is a fluid-filled body cavity.
Answer: Coelom
In simple words: A coelom is a body cavity filled with fluid. It is found in many animals and helps to protect and support their internal organs.

🎯 Exam Tip: Understand the function of the coelom as a shock absorber and a space for organ development and movement.

 

12. The body cavity of the phylum Aschelminthes is ....................
Answer: pseudocoelom
In simple words: Animals in the phylum Aschelminthes, like roundworms, have a false body cavity called a pseudocoelom. This cavity is not fully lined by mesoderm.

🎯 Exam Tip: Distinguish between true coelomates, pseudocoelomates, and acoelomates based on the presence and nature of their body cavity.

 

13. The most common diseases caused by nematodes in human beings are ............ and ............
Answer: elephantiasis, ascariasis
In simple words: Nematodes, which are roundworms, can cause diseases like elephantiasis, which makes body parts swell, and ascariasis, an infection of the intestines. These are common health problems in some areas.

🎯 Exam Tip: Be aware of common diseases caused by parasitic worms and their scientific names or classifications.

 

14. Cyclostmes are ....................
Answer: jawless vertebrates
In simple words: Cyclostomes are a group of ancient fish-like animals that do not have jaws. They are also vertebrates, meaning they have a backbone.

🎯 Exam Tip: Recognize cyclostomes as primitive vertebrates characterized by the absence of jaws and paired fins.

 

15. Malphigian tubules also called as ....................
Answer: green glands
In simple words: Malpighian tubules are special tubes that help insects and some other arthropods remove waste from their bodies. They work like kidneys. Some sources may refer to green glands (found in crustaceans) and Malpighian tubules as distinct excretory organs. However, the provided answer links them directly.

🎯 Exam Tip: Know the specific excretory organs of different invertebrate groups, as these are important for understanding their physiology.

 

16. Locomotion of phylum Echinodermata is affected by ....................
Answer: tube feet
In simple words: Echinoderms, like starfish, move around using small, muscular tubes called tube feet. These feet use water pressure to help the animal grip surfaces and move slowly.

🎯 Exam Tip: Focus on the unique water vascular system and tube feet as the primary means of locomotion for echinoderms.

III. Analogy

 

Question 1. Echinodermata: ................ :: Soft Bodies Animals: ................
Answer: Spiny Skinned Animals; Mollusca.
In simple words: Echinoderms are known for their spiny skin, while soft-bodied animals belong to the Mollusca group, like snails. This shows how different animal groups are defined by their unique features.

🎯 Exam Tip: In analogy questions, identify the relationship between the first pair to apply it correctly to the second pair. Here it's Phylum: Defining Characteristic.

 

Question 2. Birds: ................ :: ................: Cold-blooded.
Answer: Warm-blooded; Fishes.
In simple words: Birds are warm-blooded, meaning they keep a constant body temperature. In contrast, fish are cold-blooded, which means their body temperature changes with their surroundings.

🎯 Exam Tip: Clearly differentiate between warm-blooded (homeothermic) and cold-blooded (poikilothermic) animals and provide examples for each.

IV. State Whether True or False. If False Write the Correct Statement:

 

Question 1. Order is a number of related families having common characters are placed in an order.
Answer: True.
In simple words: In the classification of living things, an 'order' is a group of several 'families' that are alike in many ways. This helps organize animals and plants based on their shared features.

🎯 Exam Tip: Recall the hierarchical classification system (Kingdom, Phylum, Class, Order, Family, Genus, Species) and the relationship between each level.

 

Question 2. Tissue organization can be seen in phylum Porifera.
Answer: False.
Correct statement: Cellular grade of organization can be seen in phylum Porifera.
In simple words: Sponges (Porifera) do not have true tissues or organs; their cells work independently. They show a cellular level of organization, meaning cells are grouped but not fully organized into tissues.

🎯 Exam Tip: Understand the different levels of body organization (cellular, tissue, organ, organ-system) and which phyla represent each level.

 

Question 3. Aschelminthes is the largest phylum of the animal kingdom.
Answer: False.
Correct statement: Arthropods is the largest phylum of the animal kingdom.
In simple words: While Aschelminthes (roundworms) is a large phylum, Arthropoda (insects, spiders, crustaceans) is actually the biggest and most diverse group in the animal kingdom.

🎯 Exam Tip: Be sure to differentiate between common misconceptions and scientific facts, especially regarding the relative sizes of phyla.

 

Question 4. In the animals belonging to phylum Echinodermata, the body is divided into head, muscular food and visceral mass...
Answer: False.
Correct statement: In phylum mollusca, the body is divided into head, muscular food and visceral mass.
In simple words: Echinoderms like starfish have a central disc and radiating arms, not a distinct head, muscular foot, and visceral mass. These body parts are characteristic of molluscs, such as snails.

🎯 Exam Tip: Pay close attention to the specific body divisions and structures associated with each phylum to avoid common classification errors.

 

Question 5. Setae and parapodia are locomotor organs of earthworms.
Answer: True.
In simple words: Earthworms use tiny bristles called setae and fleshy side flaps called parapodia to move around. These structures help them grip the soil and crawl.

🎯 Exam Tip: Identify the correct locomotor structures for specific animals, as understanding how they move is a key part of their biology.

 

Question 6. Mammals have four-chambered Hearts.
Answer: True.
In simple words: Mammals, including humans, have a heart with four chambers. This design keeps oxygen-rich blood separate from oxygen-poor blood, making the circulatory system very efficient.

🎯 Exam Tip: Know the number of heart chambers for different vertebrate groups (fish, amphibians, reptiles, birds, mammals) as it's a common comparative anatomy question.

V. Match the Following:

 

Question 1.

Answer: A - iv, B - iii, C - ii, D - i
In simple words: This matching exercise connects different animal groups with examples of animals that belong to them. For instance, Coelenterata includes Hydra, Platyhelminthes includes Tapeworm, Echinodermata includes Starfish, and Mollusca includes Snail.

🎯 Exam Tip: Create flashcards for phyla and their representative examples to quickly recall these associations during exams.

VI. Assertion and Reason Type:

 

Question 1. Assertion (A): The Arthropods have an open circulatory system. Reason (R) : The cells and tissues are bathed in blood.
(a) A is right and R is wrong.
(b) A is the wrong R is right.
(c) A and R are wrong.
(d) A is right R explains A.
Answer: (d) A is right R explains A.
In simple words: Arthropods have an open circulatory system, which means their blood does not flow inside closed vessels. Instead, the blood directly surrounds and covers all their cells and tissues. So, the reason correctly explains the assertion.

🎯 Exam Tip: For Assertion-Reason questions, first check if both statements are individually true, then determine if the reason correctly explains the assertion.

 

Question 2. Assertion (A) : Mammals give birth to their young ones. Reason (R) : Platypus is an egg-laying mammal.
(a) A and R are correct.
(b) A and R are wrong.
(c) R explains A.
(d) A is the wrong R is right.
Answer: (a) A and R are correct.
In simple words: The assertion states that mammals typically give birth to live young, which is generally true. The reason correctly points out that the platypus is an exception, being an egg-laying mammal. Both statements are factually correct on their own.

🎯 Exam Tip: Be mindful of exceptions to general biological rules, as these are often used in Assertion-Reason questions to test deeper understanding.

VII. Answer in One or Two Sentences:

 

Question 1. Which organism is called Friends of farmers? Why?
Answer: Earthworms are called 'Friends of the farmers' because after digesting organic matter, earthworms excrete a nutrient-rich waste product called castings which are used as Vermicompost. Earthworms help make the soil healthier by breaking down dead plants and animals.
In simple words: Earthworms are farmer's friends because they eat dead organic stuff and turn it into rich compost (vermicompost), making the soil fertile.

🎯 Exam Tip: Explain both "what" (earthworms are friends of farmers) and "why" (their role in vermicomposting and soil enrichment) to score full marks.

 

Question 2. What are the sub-phylum of prochordates?
Answer: The sub-phyla of prochordates are Subphylum Cephalochordata and Subphylum Urochordata. These groups represent early forms of chordates with unique notochord placements.
In simple words: Prochordates are divided into two main groups: Cephalochordata and Urochordata.

🎯 Exam Tip: List all parts of a classification question to ensure a complete answer, identifying the sub-phyla clearly.

 

Question 3. Name the three germ layers.
Answer: The three germ layers are Ectoderm, Mesoderm and Endoderm. These layers develop early in an embryo and give rise to all the different tissues and organs in an animal's body.
In simple words: The three main layers that form an animal's body are ectoderm, mesoderm, and endoderm.

🎯 Exam Tip: Memorize the names and sequential order of the three germ layers, as they are fundamental to developmental biology.

 

Question 4. Name the locomotary organs seen in phylum protozoa.
Answer: The locomotory organs seen in phylum protozoa are Pseudopodia, cilia, or flagella. These tiny structures help single-celled organisms move around in their environment to find food and escape danger.
In simple words: Protozoa use pseudopodia (false feet), cilia (tiny hairs), or flagella (whip-like tails) to move.

🎯 Exam Tip: For questions about single-celled organisms like Protozoa, recall their primary methods of movement.

 

Question 5. Mention two special features of mammals.
Answer: Two special features of mammals are: (i) An external ear or pinna is seen in most mammals. (ii) Presence of the placenta is a unique characteristic feature. Mammals also feed their young with milk from mammary glands.
In simple words: Mammals often have outer ears (pinna) and a placenta to nourish babies inside the mother.

🎯 Exam Tip: When asked for "special" or "unique" features, focus on characteristics that clearly differentiate the group from others, such as pinnae and placenta for mammals.

 

Question 6. Write the binomials of a) Man b) Tapeworm
Answer: a) Man: Homo sapiens b) Tapeworm: Taenia solium. These binomial names are used worldwide to identify these species uniquely.
In simple words: The scientific name for humans is Homo sapiens, and for the tapeworm, it's Taenia solium.

🎯 Exam Tip: Practice writing binomial names correctly, with the genus capitalized and the species in lowercase, both italicized.

 

Question 7. What is the binomial name?
Answer: Carolus Linnaeus introduced the method of naming animals with two names. This is known as binomial name and is followed universally. It gives each species a unique, two-part scientific name, making communication clear across different languages and regions.
In simple words: A binomial name is a two-part scientific name given to every species, like 'Homo sapiens'. It helps scientists around the world identify animals and plants clearly.

🎯 Exam Tip: Define binomial nomenclature by mentioning its two-part structure (genus and species) and its purpose (universal identification).

VIII. Short Answer Questions:

 

Question 1. How is the body wall of coelenterates arranged?
Answer: The body wall of coelenterates is diploblastic, meaning it has two layers: an outer ectoderm and an inner endoderm. These layers are separated by a non-cellular, jelly-like substance called mesoglea. Because of these two distinct layers, coelenterates are called diploblastic animals.
In simple words: Coelenterates have a body wall made of two layers, an outer and an inner, with a jelly-like layer called mesoglea in between.

🎯 Exam Tip: Understand and clearly explain the term "diploblastic" by describing the two germ layers and the mesoglea in coelenterates.

 

Question 2. What is polymorphism?
Answer: Polymorphism is when individuals of the same species have different body forms and functions. Coelenterates often show polymorphism, where members like Hydra and Jellyfish can have different shapes and roles within their life cycle. They reproduce both asexually and sexually.
In simple words: Polymorphism means that one species can have different forms or shapes, each doing a different job.

🎯 Exam Tip: Define polymorphism and provide examples from organisms like coelenterates to illustrate how different forms serve different functions.

 

Question 3. What is the unique feature of chordates?
Answer: The unique feature of chordates is the presence of a notochord. This flexible, rod-like structure provides support and is present at some stage of development in all chordates. It is crucial for their classification.
In simple words: The main special thing about chordates is that they all have a notochord at some point in their lives.

🎯 Exam Tip: Clearly state the notochord as the defining and unique characteristic for identifying chordates.

 

Question 4. On the basis of position of notochord, classify the different prochordates. Justify your answer.
Answer:

Prochordates are classified based on where their notochord is located and how long it lasts. In Cephalochordates, the notochord is found only in the tail of the free-living larval stage. For Urochordates, the notochord stretches along the entire body length and is present throughout life. This difference in notochord position helps group them.
In simple words: Prochordates are grouped by where their notochord is: in Cephalochordata, it's only in the larva's tail; in Urochordata, it runs through the whole body for life.

🎯 Exam Tip: When classifying based on a specific feature, clearly describe how that feature varies across the different groups, using examples.

 

Question 5. List the integumentary glands of mammals.
Answer: The integumentary glands seen in mammals include sweat glands, sebaceous glands, scent glands, and mammary glands. These glands have various functions like regulating body temperature, lubricating skin, producing odors, and feeding young.
In simple words: Mammals have different skin glands like sweat glands (for cooling), sebaceous glands (for oil), scent glands (for smell), and mammary glands (for milk).

🎯 Exam Tip: List all relevant glands and briefly mention their functions to show comprehensive knowledge of mammalian integumentary features.

 

Question 6. How is the reproductive characters of mammals different from those of aves.
Answer:
In simple words:

🎯 Exam Tip: When comparing two groups, ensure to highlight contrasting features for each point of comparison, focusing on clear differences.

 

Question 7. Mention two characteristic features of phylum Echinodermata.
Answer: Echinoderms have a special water vascular system, which helps them move and catch food. They also use small tube-like feet for moving around and capturing food. This unique system uses water pressure to help them perform various functions.
In simple words: Echinoderms have a water vascular system and use tube feet to move.

🎯 Exam Tip: Think about what makes echinoderms special and list two distinct features, like their unique water system or tube feet.

 

Question 8. Mention two features seen in Aves to aid in flying.
Answer: Birds have front limbs that have changed into wings, which they use for flying. Their bones are hollow and filled with air (called pneumatic bones), making their bodies lighter for easier flight. These adaptations are crucial for birds to conquer the skies.
In simple words: Birds have wings for flying and light, air-filled bones that help them stay light in the air.

🎯 Exam Tip: When asked about adaptations for a specific function, focus on structural changes directly related to that function.

 

Question 9. Why is crocodile unique among reptiles?
Answer: Crocodiles are special among reptiles because they have a four-chambered heart. Most other reptiles, in contrast, have a three-chambered heart. This advanced heart structure allows for more efficient oxygen delivery, similar to mammals and birds.
In simple words: Crocodiles are unique because they have a four-chambered heart, while most other reptiles only have three heart chambers.

🎯 Exam Tip: Remember key exceptions to general biological rules, as these often highlight evolutionary advancements or unique adaptations.

 

Question 10. Why are eggs of reptiles covered with shell unlike eggs of amphibians?
Answer: Reptiles are vertebrates that are well-adapted for living on land. They lay eggs with a tough outer shell, like those of Calotes, lizards, snakes, tortoises, and turtles. This shell protects the developing baby inside from drying out and other dangers on land. Amphibian eggs, however, are laid in water and lack this hard shell, as they rely on the water for moisture. This adaptation allowed reptiles to fully move away from water for reproduction.
In simple words: Reptiles have hard-shelled eggs to protect them on land, while amphibians lay their soft eggs in water.

🎯 Exam Tip: Connect adaptations like shelled eggs directly to the environment an animal lives in (terrestrial vs. aquatic).

 

Question 11. What are pneumatic bones?
Answer: Pneumatic bones are bones that are hollow and filled with air. These special bones are commonly found in birds (aves). The air-filled nature of these bones makes them lightweight, which is essential for flight.
In simple words: Pneumatic bones are hollow bones filled with air, usually found in birds, which make them lighter.

🎯 Exam Tip: Define the term clearly and provide an example of where it is found to get full marks.

IX. Long Answer Questions:

 

Question 1. Write a note on mammals.
Answer:

• Mammals are warm-blooded animals, meaning they can keep their body temperature steady.
• Their skin is covered with hair, and they also have sweat and oil glands.
• Their body parts include a head, neck, main body (trunk), and a tail.
• Female mammals have mammary glands that make milk to feed their babies.
• They have external ears, also known as pinnae.
• Mammals have a four-chambered heart and breathe using lungs.
• Most mammals give birth to live young (this is called viviparous), except for a few like the platypus and spiny anteater, which lay eggs.
• A unique feature of many mammals is the placenta, which helps the baby grow inside the mother, for example in rats, rabbits, and humans.

These diverse features allow mammals to thrive in nearly every habitat on Earth.
In simple words: Mammals are warm-blooded animals with hair, external ears, and mammary glands for feeding young. They have a four-chambered heart, breathe with lungs, and mostly give birth to live babies, often using a placenta.

🎯 Exam Tip: When writing notes on an animal group, cover key aspects like body temperature, covering, key organs (heart, lungs), and reproductive methods.

 

Question 2. Write a note on aves.
Answer:

• Birds are warm-blooded animals that have many special features to help them fly.
• Their body is shaped like a spindle or boat, and it has a head, neck, main body, and tail.
• Their bodies are covered with feathers. Their front limbs have changed into wings for flying.
• Their back limbs are made for walking, sitting on branches, or swimming.
• They breathe using lungs, which are connected to air sacs.
• Their bones are hollow and filled with air (called pneumatic bones), making them lighter.
• Birds lay eggs that have a large amount of yolk.
• Their eggs are covered with a hard, chalky shell, for example, the eggs of parrots, crows, eagles, pigeons, and ostriches.

These combined features make birds master aviators in the animal kingdom.
In simple words: Birds are warm-blooded animals with feathers and wings for flying. They have light, air-filled bones, lungs with air sacs, and lay large, hard-shelled eggs.

🎯 Exam Tip: Similar to mammals, cover distinct characteristics like body covering, unique skeletal features, respiratory system, and reproductive strategy.

 

Question 3. Outline the flow chart of invertebrate phyla.
Answer:

In simple words: This chart shows how different animal groups (phyla) are classified. It starts with simple animals with only cells and moves to more complex ones with body systems, different body shapes, and internal body cavities.

🎯 Exam Tip: When outlining classifications, present the hierarchy clearly, starting from broad categories and moving to specific phyla based on key distinguishing features.