RBSE Solutions Class 9 Science Chapter 7 Bio-Diversity

Objective Type Questions

 

Question 1. The highly advanced division of plant is:
(a) Bryophyta
(b) Angiosperm
(c) Gymnosperm
(d) Thallophyta
Answer: (b) Angiosperm
In simple words: The angiosperms are the most evolved group of plants, known for their ability to produce flowers and fruits. They represent a significant advancement in plant evolution.

🎯 Exam Tip: Remember that angiosperms are flowering plants, which helps to easily distinguish them as the most advanced plant division.

 

Question 2. In which plant seed, vivipary is found
(a) Hydrophytes
(b) Mesophytes
(c) Xerophytes
(d) Halophytes
Answer: (d) Halophytes
In simple words: Vivipary is when a seed starts to sprout while it's still attached to the parent plant. This is often seen in plants that grow in salty marsh areas, called halophytes.

🎯 Exam Tip: Vivipary is a key adaptation for plants in harsh environments, especially saline ones, as it allows the seedling to develop in a protected environment before facing challenging external conditions.

 

Question 3. Sunken stomata in the leaves is an adaptation of:
(a) Xerophytes
(b) Halophytes
(c) Hydrophytes
(d) Mesophytes
Answer: (a) Xerophytes
In simple words: Sunken stomata are like tiny pits on a leaf's surface where pores are located. This design helps desert plants (xerophytes) save water by reducing how much moisture escapes into the air.

🎯 Exam Tip: Adaptations like sunken stomata are crucial for xerophytes to survive in dry conditions, as they minimize water loss through transpiration.

 

Question 4. In which plant division, plants are known as vascular cryptogams:
(a) Pteridophyta
(b) Bryophyta
(c) Gymnosperm
(d) None of these
Answer: (a) Pteridophyta
In simple words: Pteridophytes are plants that have a system for moving water and food inside them (vascular tissue), but they reproduce using spores instead of seeds. They are a kind of cryptogam, meaning their reproductive parts are hidden.

🎯 Exam Tip: Remember "vascular cryptogams" refers to plants with vascular tissue but no seeds, a key characteristic of pteridophytes like ferns.

 

Question 6. Name the father of binomial nomenclature of classification?
Answer: Carolus Linnaeus is known as the father of binomial nomenclature. He developed the system where each species gets a two-part scientific name, which helps in clear identification globally.
In simple words: Carolus Linnaeus created the way we name living things with two scientific words.

🎯 Exam Tip: Knowing Linnaeus's contribution to binomial nomenclature is fundamental for understanding biological classification.

 

Question 7. Does frog belong to which class?
Answer: The frog belongs to the class Amphibia. Amphibians are a group of vertebrates that can live both on land and in water, showcasing a unique dual lifestyle.
In simple words: Frogs are in the Amphibia class.

🎯 Exam Tip: Remember that amphibians have a distinctive life cycle, often starting in water and moving to land, which helps classify them.

 

Question 8. What is Adaptation?
Answer: Adaptation refers to the special features or characteristics that help plants and animals live successfully in a particular environment. These features allow them to survive and thrive in their surroundings.
In simple words: Adaptation means the special traits that help living things survive in their home.

🎯 Exam Tip: When defining adaptation, emphasize both the "special characteristics" and their role in helping organisms "live successfully" in their environment.

 

Question 9. Who proposed the five kingdom classification?
Answer: Robert H. Whittaker proposed the five kingdom classification in 1969. His system categorized living organisms into Monera, Protista, Fungi, Plantae, and Animalia.
In simple words: Robert H. Whittaker created the five kingdom classification system in 1969.

🎯 Exam Tip: Always include the name of the scientist (Whittaker) and the year (1969) when discussing the five-kingdom classification for full marks.

 

Question 10. Cynobacteria belongs to which kingdom?
Answer: Cyanobacteria belongs to the kingdom Monera. This kingdom includes all prokaryotic organisms, which lack a true nucleus and membrane-bound organelles.
In simple words: Cyanobacteria are part of the Monera kingdom.

🎯 Exam Tip: Recall that Monera includes all bacteria and blue-green algae (cyanobacteria) because they are single-celled organisms without a proper nucleus.

 

Question 11. What is Lichen?
Answer: Lichen is a unique life form created by a close, mutually beneficial partnership between an alga and a fungus. They grow together on tree bark as colorful patches, with the fungus providing structure and protection, and the alga producing food through photosynthesis.
In simple words: Lichen is a mix of algae and fungi living together, often seen as colored spots on trees.

🎯 Exam Tip: The key term for lichens is "symbiotic relationship" or "mutual association" between an alga and a fungus, highlighting their interdependence.

 

Question 13. Name the animal which respire through gills, lungs and skin?
Answer: The frog, from the class Amphibia, can breathe using its gills when young, lungs as an adult, and skin throughout its life. This ability helps it survive in both aquatic and terrestrial environments.
In simple words: The frog can breathe through its gills, lungs, and skin.

🎯 Exam Tip: The frog's multiple respiratory organs are a classic example of adaptation for an amphibian's dual lifestyle, allowing it to take in oxygen from both water and air.

 

Question 14. Name two animals which lay eggs?
Answer: Two animals that lay eggs are the Platypus and the Echidna. These are unique mammals known as monotremes, which reproduce by laying eggs instead of giving birth to live young.
In simple words: Platypus and Echidna are two animals that lay eggs.

🎯 Exam Tip: While most mammals give birth to live young, remembering the egg-laying monotremes (Platypus and Echidna) shows a deeper understanding of animal diversity.

 

Question 15. In which habitat mangrove vegetation is found?
Answer: Mangrove vegetation is found in halophytic, saline, and marshy habitats. These are coastal areas where freshwater mixes with saltwater, creating unique and challenging conditions for plant growth.
In simple words: Mangroves grow in salty, wet coastal areas.

🎯 Exam Tip: Mangroves thrive in specific conditions (saline, marshy, halophytic) due to special adaptations that allow them to tolerate high salt concentrations.

Bio-Diversity Short Answer Type Questions

 

Question 16. Write the general characters of Halophytes?
Answer: Halophytes are special types of xerophytes that grow in saline soil with a high concentration of salts like sodium chloride, magnesium sulfate, and magnesium chloride. They are commonly found near saline lakes (such as Sambhar Lake) and along ocean coasts. These plants have several adaptations to survive in their salty environment:

• A unique type of roots called pneumatophores grows vertically upwards from underground stems. These conical spikes have many pores at their upper end for exchanging gases like oxygen and carbon dioxide.
• Stems are often fleshy and covered with hairs.
• Leaves are typically less developed and fleshy.
• Most halophytes show vivipary, where seeds germinate inside the fruit while still attached to the parent tree. These germinated seeds then fall onto the soil and begin to develop. For example, Rhizophora and Sonnertia are common halophytes.

In simple words: Halophytes are plants that live in salty places. They have special roots that grow upwards to get air, fleshy stems, small leaves, and often their seeds start growing while still on the parent plant.

🎯 Exam Tip: When describing halophytes, always mention their adaptations to high salinity and waterlogged conditions, such as pneumatophores and vivipary, as these are distinguishing features.

 

Question 17. Write the adaptation found in aquatic animals?
Answer: Aquatic environments are crucial habitats for many animals, including both freshwater and marine species like fish, seals, dolphins, and whales. These animals develop specific adaptations to thrive in water. The key structural and functional adaptations of aquatic animals are:

• For movement: Most aquatic animals have streamlined or spindle-shaped bodies, which are laterally compressed. This shape helps reduce resistance when swimming through water, making movement easier. Animals move in water using fins (fish), flippers (whales), or webbed feet (frogs and ducks).
• For protection: Their bodies are covered with waterproof layers like scales, cuticles, or shells, and often a slippery substance. These coatings help reduce surface tension and protect the animal.
• For feeding: Aquatic animals have specialized abilities and structures to feed efficiently in water.
• For obtaining dissolved oxygen: Gills are the primary respiratory organs in most aquatic animals, having a large surface area to efficiently extract oxygen dissolved in water. Mammals like dolphins use lungs for breathing.
• For remaining buoyant: Adaptations like swimbladders help animals stay afloat in water.
• For balancing pressure: Aquatic animals are adapted to manage pressure fluctuations in their watery habitat.

In simple words: Aquatic animals have bodies shaped to swim fast, use fins or flippers for moving, and have waterproof skin for protection. They breathe using gills or lungs and have ways to float and handle water pressure.

🎯 Exam Tip: When discussing aquatic adaptations, focus on how body shape (streamlined), respiratory organs (gills/lungs), and coverings (scales/slippery skin) help animals overcome the challenges of living in water.

 

Question 19. Write the characteristics of Class Mammalia.
Answer: Class Mammalia includes a wide range of animals like kangaroos, bats, monkeys, cows, and humans. Mammals possess several distinct characteristics:

• Females have developed mammary glands to feed milk to their young.
• Their body is typically divided into a head, neck, thorax, and tail.
• Hair is present on their body, providing insulation.
• External ear pinnae are present.
• Mammals are warm-blooded, meaning they maintain a constant body temperature.
• Respiration occurs through lungs.
• The heart is four-chambered, consisting of two auricles and two ventricles.
• Most mammals are viviparous, meaning they give birth to live young.

Examples include Pteropus (bat), Homo (man), Herpestes (mongoose), Rattus (rat), Panthera (lion, tiger).
In simple words: Mammals feed their babies milk, have hair, warm bodies, and breathe with lungs. Their heart has four parts, and most give birth to live young.

🎯 Exam Tip: For mammals, key characteristics to mention are mammary glands, hair, warm-blooded nature, and viviparity, as these largely define the class.

 

Question 20. Write the characterises of Phylum Arthropoda?
Answer: Phylum Arthropoda means "animals with jointed legs". This is the largest phylum in the animal kingdom, characterized by:

• Jointed appendages that are modified for various functions like walking, flying, or feeding.
• An exoskeleton made of chitin, which provides protection and support.
• A segmented body, typically divided into a head, thorax, and abdomen.
• Bilateral symmetry.

Examples of Arthropods include the housefly, grasshopper, crab, scorpion, butterfly, and cancer (another term for crab).
In simple words: Arthropods are animals with jointed legs and a hard outer shell. Their bodies are divided into segments, and they include insects, spiders, and crabs.

🎯 Exam Tip: The defining features of Arthropoda are "jointed appendages" and an "exoskeleton", which are essential for their movement and protection.

 

Question 21. In Gymnosperm plants, write the function of mycorrhiza and coralloid roots.
Answer: Gymnosperms, like the evergreen Pinus, are perennial plants with a well-differentiated root, stem, and leaves. They possess a taproot system, but their lateral roots spread out extensively.

• Mycorrhiza: This is a symbiotic relationship between the main roots of gymnosperms and soil fungi. The fungus helps the plant absorb water and nutrients from the soil, while the plant provides sugars to the fungus.
• Coralloid root: In some gymnosperms, particularly cycads, small adventitious roots called coralloid roots grow near the surface. These roots form a partnership with cyanobacteria (blue-green algae), which are capable of fixing atmospheric nitrogen into a form usable by the plant, enriching the soil.

In simple words: Mycorrhiza helps gymnosperm roots get more water and food from the soil with the help of fungi. Coralloid roots work with special bacteria to add nitrogen to the soil.

🎯 Exam Tip: For this question, clearly explain the mutualistic nature of both relationships, specifying who benefits from whom for both mycorrhiza and coralloid roots.

 

Question 22. Explain Symbiosis in Lichens?
Answer: In lichens, symbiosis means that an alga and a fungus live closely together and both benefit from the relationship. The fungus provides a protective shelter for the alga and also helps maintain the necessary humidity inside the lichen body. This humid environment is crucial for the alga to perform photosynthesis properly. In return, the alga produces food through photosynthesis and provides it to the fungus. This mutual association allows both organisms to thrive in environments where neither could survive alone.
In simple words: Lichens show symbiosis because a fungus gives shelter to an alga, and the alga makes food for the fungus using sunlight. They help each other live.

🎯 Exam Tip: When explaining symbiosis in lichens, clearly state the distinct roles of both the fungal and algal components and how each benefits the other.

 

Question 23. Why the plants of Pteridophyta called Cryptogams?
Answer: Plants of Pteridophyta are called Cryptogams because their reproductive organs are hidden and not easily visible. Unlike flowering plants, they do not produce external flowers or seeds. Instead, they reproduce using naked embryos called spores. The term "Cryptogams" literally means "hidden reproduction," which accurately describes this group of plants.
In simple words: Pteridophyte plants are called Cryptogams because their parts for making new plants are hidden, and they make spores instead of flowers or seeds.

🎯 Exam Tip: The key reason pteridophytes are cryptogams is their reliance on spores for reproduction and the absence of visible flowers or seeds.

 

Question 24. Describe the adaptation found in Xerophytes plant?
Answer: Xerophytes are plants that have adapted to survive in very dry or desert environments. They have several features to conserve water and tolerate arid conditions:

• Their roots are usually long and grow deep into the soil to find water.
• Leaves are often small and modified into spines, which helps reduce water loss through transpiration.
• Stomata (pores for gas exchange) are typically sunken, and a thick, waxy cuticle is present on the epidermis of stems and leaves. These features also help in reducing water loss.
• Some succulent xerophytes have fleshy leaves and stems that store water, acting as natural water reservoirs.
• Mechanical tissues in the stem are well developed, and stems can be spongy and store water, sometimes covered with dense hairs to reduce evaporation.

In simple words: Xerophytes, or desert plants, have long roots, small spiny leaves, and thick waxy skin to save water. Some also store water in their fleshy stems.

🎯 Exam Tip: When describing xerophyte adaptations, focus on features that either reduce water loss (spines, sunken stomata, cuticle) or enhance water storage (fleshy stems/leaves) and absorption (long roots).

 

Question 25. What are saprophytes?
Answer: Saprophytes are organisms, primarily fungi, that get their nutrition from decaying organic matter. They act as decomposers by breaking down dead plants and animals, playing a vital role in nutrient cycling in ecosystems. Examples include Mucor and Rhizopus.
In simple words: Saprophytes are living things, like fungi, that eat dead plants and animals to get food.

🎯 Exam Tip: The core idea of saprophytes is their role as "decomposers" that obtain nutrients from "decaying organic matter."

 

Question 26. Define the two similarities between the Bryophyta and Pteridophyta group?
Answer: Bryophytes and Pteridophytes share two key similarities:

• Both groups have hidden reproductive organs that are not easily visible.
• They both lack external flowers and seeds, instead reproducing via spores. The embryos are "naked," meaning they are not enclosed within seeds. For this reason, both are classified under 'Cryptogamae'.

In simple words: Both bryophytes and pteridophytes have hidden ways to reproduce and do not make flowers or seeds, using spores instead.

🎯 Exam Tip: Emphasize the "hidden reproductive organs" and reproduction via "spores" as the main commonalities between bryophytes and pteridophytes.

 

Question 27. What are monocot and dicot plants?
Answer: Monocot and dicot plants are two major groups of flowering plants, distinguished by several features:

• Monocots: The seeds of these plants have only one cotyledon (seed leaf). Their leaves typically show parallel venation. They have a fibrous root system. Their flowers usually have three petals or multiples of three. Vascular bundles are scattered and closed, meaning they lack cambium and thus no secondary growth. Examples include maize, rice, sugarcane, wheat, onion, coconut, grasses, and banana.
• Dicots: The seeds of these plants have two cotyledons. Their leaves exhibit reticulate (net-like) venation. They have a taproot system, including primary and secondary roots. Their flowers typically have five petals or multiples of five. Vascular bundles are arranged in a ring and are open, containing cambium, which allows for secondary growth. Examples include potato, pea, sunflower, rose, neem, apple, and banyan.

In simple words: Monocot plants have one seed leaf, parallel veins in leaves, and flowers with three parts. Dicot plants have two seed leaves, net-like veins, and flowers with five parts.

🎯 Exam Tip: When differentiating monocots and dicots, focus on the number of cotyledons, leaf venation, root system, and flower parts as primary distinguishing characteristics.

 

Question 28. Write the two differences between chordates and non-chordates?
Answer: Here are two main differences between chordates and non-chordates:

• Nerve Cord: Chordates have a nerve cord located on the mid-dorsal (back) surface of their body. In contrast, non-chordates either lack a nerve cord, or if present, it is located on the mid-ventral (front) surface.
• Pharyngeal Gill Clefts: Chordates possess pharyngeal gill clefts (or slits) at some stage of their life cycle. Non-chordates, however, do not have any pharyngeal gill clefts at any stage of their life.

In simple words: Chordates have a nerve cord on their back and gill slits at some point in life. Non-chordates do not have these features or have their nerve cord on their front.

🎯 Exam Tip: The presence and position of the nerve cord and pharyngeal gill clefts are key anatomical features for distinguishing between chordates and non-chordates.

 

Question 29. What is the function of pneumatophores in Halophytes?
Answer: Halophytes often grow in water-logged soils where the roots cannot get enough air for respiration. To overcome this, their underground roots grow upwards, out of the soil and water surface. These aerial roots are called pneumatophores, or respiratory roots. They appear like conical spikes and are negatively geotropic, meaning they grow against gravity. Pneumatophores have numerous aerating pores that allow them to absorb oxygen directly from the atmosphere, thus performing the crucial function of respiration for the submerged root system.
In simple words: Pneumatophores are special roots that grow upwards from waterlogged soil to help halophyte plants breathe, as their main roots don't get enough air.

🎯 Exam Tip: Emphasize that pneumatophores are an adaptation for "respiration" in "water-logged, oxygen-deficient soil" and that they grow "upwards" to access air.

 

Question 30. What is the function of assimilatory root in Trapa?
Answer: In Trapa, the water chestnut, the assimilatory roots are modified to perform photosynthesis. These roots are green and remain hanging freely in the air or water. Their primary function is to capture sunlight and produce food material for the plant, much like leaves do in other plants. This is a special adaptation for plants that live in aquatic environments.
In simple words: Assimilatory roots in Trapa are green roots that hang in the air and make food for the plant using sunlight, just like leaves.

🎯 Exam Tip: The main function of assimilatory roots in Trapa is "photosynthesis," highlighting a unique adaptation where roots take on the role typically performed by leaves.

 

Question 31. Write the adaptation found in aerial animals?
Answer: Aerial animals are those that live and thrive mainly on land but often use trees or their branches for safety and shelter. Examples include monkeys, flying lizards, flying squirrels, bats, and birds. Birds and bats, in particular, show specific adaptations for an aerial (flying) mode of life:

• Body Shape: Their bodies are streamlined (spindle-shaped) to allow for easy and swift movement through the air, minimizing drag.
• Forelimbs: Forelimbs are modified into wings, which are essential for flying.
• Covering: The entire body of birds is covered by light, elastic, and waterproof feathers, which aid in flight and also help maintain body temperature.
• Skeletal Structure: Birds have hollow bones, which make their bodies lighter for flight. They also possess strong flight muscles.
• Other Features: They have a light body covering, sharp eyesight, modified beaks, and tails for steering. Birds typically lack teeth and a urinary bladder to further reduce weight.
• Reproductive Organs: The ovary and oviduct are single, and lungs are equipped with air sacs that are air-filled, making the body lighter for flight.

In simple words: Aerial animals like birds and bats have bodies shaped like spindles, wings instead of front legs, and light feathers or hollow bones to help them fly easily.

🎯 Exam Tip: For aerial adaptations, emphasize the features that reduce weight (hollow bones, single ovary) and improve aerodynamics/lift (streamlined body, wings, feathers).

 

Question 32. Classify plants, on the basis of habitat and describe all the adaptations found in Plants?
Answer: Adaptation refers to the special characteristics that help plants and animals live successfully in a particular environment. Warming classified plants into the following categories based on the amount of water available in their different environments:
1. Hydrophytes
2. Xerophytes
3. Halophytes
4. Mesophytes

1. Hydrophytes: These are plants that grow in water or in very wet places, commonly found in ponds, lakes, or rivers. Adaptations in Hydrophytes include:

• Roots are either absent or poorly developed, and root caps are typically absent.
• Stems are long, slender, spongy, and flexible. Mechanical tissues like sclerenchyma are absent or poorly developed, allowing flexibility in water currents.
• Leaves are thin, long, and ribbon-shaped. Leaves floating on the water surface are generally long, cylindrical, smooth, and dark-colored, often with a wax-like substance on their upper surface to prevent wetting.

2. Xerophytes: These are plants adapted to dry conditions.

• The roots of xerophytes are usually long and grow deep into the subsoil to search for water.
• Leaves are small and often modified into spines to reduce transpiration.
• A thick cuticle is found on stems and leaves, and stomata are sunken, further minimizing water loss.
• Succulent xerophytes have fleshy leaves and stems that store water in their water storage tissues.

3. Halophytes: These are special types of xerophytes that grow in saline soils with high concentrations of salts like sodium chloride, magnesium sulfate, and magnesium chloride. Halophytes are found near saline lakes and on ocean coasts. Adaptations in Halophytes include:

• A special type of roots called pneumatophores grows vertically upwards from underground stems. These conical spikes have numerous pores at their upper end for the exchange of vital gases like oxygen and carbon dioxide.
• Most halophytes show vivipary, where seeds germinate inside the fruit while still attached to the parent tree. The germinated seeds fall onto the soil and begin to develop. For example, Rhizophora.

4. Mesophytes: These are plants that grow under average conditions of temperature and moisture. Examples include Peepal, Neem, Maize, Wheat, Guava, etc.
In simple words: Plants are grouped by how much water they need: Hydrophytes live in water, Xerophytes live in dry places, Halophytes live in salty areas, and Mesophytes live in normal conditions. Each group has special features like root type, leaf shape, and stem structure to survive in their environment.

🎯 Exam Tip: For this comprehensive question, ensure you clearly define adaptation, list all four plant types, and provide at least two specific adaptations for each type to demonstrate a thorough understanding.

 

Question 33. Write the conventions, while writing the scientific name followed by the Binomial method.
Answer: Nomenclature is a system used to assign unique scientific names to organisms, which helps in classifying them. Scientific names consist of two words: the first word represents the genus, and the second word represents the species. These names are unique and can identify an organism anywhere in the world. Several conventions are followed when writing scientific names:

• The genus name always begins with a capital letter.
• The species name always begins with a small letter.
• When written by hand, both the genus and species names must be underlined separately.
• When printed, the scientific name is written in italics.

In simple words: When writing a scientific name, the first part (genus) starts with a capital letter, and the second part (species) starts with a small letter. You underline it when writing by hand or use italics when printing.

🎯 Exam Tip: Remember the four key rules for binomial nomenclature: capital for genus, small for species, underline when handwritten, and italicize when typed. This ensures correct scientific communication.

 

Question 34. Describe the characteristics and examples of Aquatic and Desert animals?
Answer: Aquatic habitats are vital environments for many animals, including both freshwater and saltwater species. Animals living on land show diverse habits, such as cursorial adaptations for walkers/runners, fossorial adaptations for burrowers, and arboreal adaptations for climbers and fliers. Desert animals have specific xeric adaptations to overcome harsh desert conditions.

Adaptive features of aquatic animals are:

• Body Shape: The body is streamlined or spindle-shaped, which helps reduce resistance while swimming.
• Respiratory Organs: Gills are the main respiratory organs in fishes, with a large surface area to extract dissolved oxygen.

In amphibious adaptation, a frog is adapted for both aquatic and terrestrial life:

• Limbs: Webbed feet are adapted for swimming. Hind limbs are longer for jumping on land.
• Skin: Skin is always moist, aiding in breathing on land.
• Reproduction: Fertilization is external, typically occurring in water.

Xeric adaptations of Desert animals:
Animals like camels, desert rats, rabbits, and foxes have adapted to arid conditions.
Some xeric adaptations are as follows:

• Water Absorption: Animals like Moloch absorb water through their skin, similar to blotting paper. Their surface is covered by thorn-like scales.
• Water Storage: Camels develop water cells in their walls and use their entire foot for walking.
• Water Conservation: Desert animals do not perspire much to conserve water.
• Nostrils and Eyes: A camel's nostril can close like an eyelid, and eyelids are modified to form a window-like structure that covers the eye, protecting against sand.
• Sensory Organs: Ear openings are small or protected by scales. The senses of sight, hearing, and smell are highly developed to navigate the desert environment.

In simple words: Aquatic animals are shaped for swimming and use gills or lungs to breathe. Frogs can live in both water and land, using webbed feet and moist skin. Desert animals like camels save water, have special ways to close their nostrils, and sharp senses to survive dry places.

🎯 Exam Tip: When describing animal adaptations, categorize them by function (e.g., body shape for movement, skin for protection, gills for respiration) for clarity and completeness.

 

Question 35. Describe the characteristics of Angiosperm and Gymnosperm Plants?
Answer: Plants are classified based on the presence or absence of distinct body components. The first level separates algae (simple thalloid body) from others. Further classification considers vascular tissues, then the ability to bear seeds, and finally whether seeds are naked or enclosed in fruits.

The characteristics of angiosperms are as follows:
Angiosperms are divided into two groups based on the number of cotyledons in the seed:

• Dicotyledonous or Dicots plants: Have two cotyledons in their seeds.
• Monocotyledonous or Monocots Plants: Have one cotyledon in their seeds.

Angiosperms are known for producing flowers and enclosing their seeds within fruits.

Gymnosperms:
Gymnosperms are often considered more primitive plants that bear naked seeds, meaning their seeds are not enclosed within fruits. Key characteristics include:

• The seeds produced are naked and not enclosed within fruits.
• They are typically perennial, evergreen, and woody plants.
• Sporophylls (spore-bearing leaves) are grouped to form cones, which are separated into male and female cones.
• Xylem lacks true vessels, and phloem lacks companion cells.
• They have haploid endosperm cells.

In simple words: Angiosperms are flowering plants that have seeds inside fruits and are divided into monocots (one seed leaf) and dicots (two seed leaves). Gymnosperms are plants with naked seeds, meaning their seeds are not covered by fruits, and they often grow in cones.

🎯 Exam Tip: The crucial distinction between angiosperms and gymnosperms lies in whether their "seeds are enclosed within fruits" (angiosperms) or "naked" (gymnosperms).

 

Question 36. Write short notes on:
(a) Mangrove vegetation.
(b) Amphibians of Plant kingdom.
(c) Mineral excretory glands.
(d) Lichen.
(e) Stilt roots.
Answer:
(a) Mangrove vegetation: Halophytes are specialized xerophytes that grow in saline soils, which have high concentrations of sodium chloride, magnesium sulfate, and magnesium chloride. These plants are found in coastal lands, deltas, and river estuaries. Mangrove plants show a unique type of seed germination called vivipary, where seeds germinate while still attached to the parent plant. This is an essential adaptation in saline, muddy soils because the high salt concentration in water prevents seeds from germinating if they fall to the ground directly. Adventitious roots developing from the main stems also support these plants in the soil. Some mangroves develop respiratory roots (pneumatophores) that grow above the soil to exchange gases.
In simple words: Mangrove plants live in salty, wet coastal areas. Their seeds sprout while still on the tree (vivipary), and they have special roots that grow up to breathe.

🎯 Exam Tip: When describing mangrove vegetation, highlight their adaptation to saline environments, specifically mentioning vivipary and pneumatophores as key survival strategies.

Bio-Diversity Rajasthan Board Solutions Additional Questions Solved

Multiple Choice Questions (MCQs)

 

Question 1. Plants growing in saline water are called as-
(a) Mesophytes
(b) Halophytes
(c) Xerophytes
(d) Hydrophytes
Answer: (b) Halophytes
In simple words: Plants that grow in very salty water environments are called halophytes. They have special adaptations to survive in such conditions, often found in coastal areas.

🎯 Exam Tip: Remember that "halo" often relates to salt, helping you recall terms like halophytes (salt-loving plants).

 

Question 2. In Volant or aerial animals, the forelimbs are modified into-
(a) Wings
(b) Hind limbs
(c) Body
(d) Air chambers
Answer: (a) Wings
In simple words: For animals that fly, like birds and bats, their front limbs have changed over time to become wings. These wings help them move through the air.

🎯 Exam Tip: Think about the main purpose of forelimb modification in flying animals - it's always for flight.

 

Question 3. In Whittaker's classification, unicellular organisms are grouped under-
(a) Porifera
(b) Protozoa
(c) Protista
(d) Fungi
Answer: (c) Protista
In simple words: According to Whittaker's five-kingdom classification system, all single-celled organisms that have a nucleus (eukaryotes) are placed in the kingdom Protista. This includes a wide variety of tiny life forms.

🎯 Exam Tip: Differentiate Protista (unicellular eukaryotes) from Monera (unicellular prokaryotes) in Whittaker's system.

 

Question 4. The general rule for writing a scientific names is-
(a) the generic name followed by a species name, that begins with a small letter
(b) the species name followed by a generic name
(c) the generic name beginning with a small letter
Answer: (a) the generic name followed by a species name, that begins with a small letter
In simple words: When writing scientific names, the rule is to first write the genus name, which starts with a capital letter, and then the species name, which starts with a small letter. Both parts are usually italicized.

🎯 Exam Tip: Remember "Genus species" - capital G, lowercase s, both italicized (or underlined if handwritten).

 

Question 6. Which one is a characteristic of xerophyte-
(a) Aerenchyma
(b) Large leaves
(c) Sunken stomata
(d) Poorly developed roots
Answer: (c) Sunken stomata
In simple words: A key feature of xerophytes, which are plants adapted to dry conditions, is having stomata that are sunk below the leaf surface. This helps them reduce water loss.

🎯 Exam Tip: Remember that xerophytes adapt to conserve water, and sunken stomata are a direct way to achieve this by reducing exposure to dry air.

 

Question 7. Pneumatophores are found in-
(a) Mesophyte plants
(b) Xerophyte plants
(c) Mangrove plants
(d) In all the options
Answer: (c) Mangrove plants
In simple words: Pneumatophores are special breathing roots that are found in mangrove plants. These roots grow upwards from the soil to help the plant get oxygen in waterlogged conditions.

🎯 Exam Tip: Connect "pneumato-" with air/breathing, and "mangrove" with waterlogged, oxygen-poor soil to remember the function of pneumatophores.

 

Question 8. Which of the following plants has a flat stem-like leaf-
(a) Opuntia
(b) Hydrilla
(c) Vallisnaria
(d) Lotus
Answer: (a) Opuntia
In simple words: Opuntia, which is a type of cactus, has flattened, stem-like structures that act like leaves for photosynthesis and water storage. These are called cladodes.

🎯 Exam Tip: Associate Opuntia with desert plants and their unique adaptations, like flattened stems, to survive dry conditions.

 

Question 9. Which adaptation is not found in aquatic plants?
(a) Conducting tissue system is under developed
(b) Root system well developed
Answer: (b) Root system well developed
In simple words: Aquatic plants, living in water, do not typically need a well-developed root system because they can absorb water and nutrients directly from their surroundings. Their roots are often reduced or absent.

🎯 Exam Tip: Think about the environment: aquatic plants are surrounded by water, so extensive roots for water absorption are less necessary compared to land plants.

 

Question 10. Plants of which division of plant kingdom cannot be differentiated into roots, stem and leaf
(a) Thallophyta
(b) Angiosperms
(c) Pteridophyta
(d) Gymnosperms
Answer: (a) Thallophyta
In simple words: In the plant kingdom, members of the Thallophyta division, which includes algae, have a simple body structure that cannot be clearly divided into distinct roots, stems, or leaves.

🎯 Exam Tip: Thallophyta represents the most primitive group of plants, often characterized by a 'thalloid' body lacking true differentiation.

 

Question 11. The connecting link between non-living and living is-
(a) Bacteria
(b) Virus
(c) Amoeba
(d) Euglena
Answer: (b) Virus
In simple words: Viruses are often considered a link between non-living and living things because they show characteristics of life (like reproduction) only when inside a host cell, but behave like non-living chemicals outside a host.

🎯 Exam Tip: Remember viruses lack cellular structure and metabolic machinery, making them dependent on host cells, hence their unique classification.

 

Question 12. The basic characteristic of chordates are-
(a) Presence of a notochord and a nerve cord.
(b) Presence of a nerve cord, notochord and gill left.
(c) Presence of a nerve cord and gill cleft.
(d) None of the options.
Answer: (c) Presence of a nerve cord and gill cleft.
In simple words: Chordates are animals that, at some point in their lives, have a notochord (a flexible rod), a dorsal hollow nerve cord, pharyngeal gill slits (or clefts), and a post-anal tail. Option (c) mentions nerve cord and gill cleft, which are two of these key features.

🎯 Exam Tip: The four main distinguishing features of chordates are: notochord, dorsal hollow nerve cord, pharyngeal slits, and post-anal tail.

 

Question 13. Tapeworm belongs to phylum-
(a) Porifera
(b) Annelida.
(c) Placental animal
(d) Corvus splendens
Answer: (d) Corvus splendens
In simple words: Corvus splendens is the scientific name for the house crow, a type of bird. Tapeworms, on the other hand, are flatworms that belong to the phylum Platyhelminthes.

🎯 Exam Tip: It is crucial to learn the correct phyla for common organisms to avoid misclassification. Scientific names identify specific species, not entire phyla.

 

Question 14. Birds are-
(a) Oviparous
Answer: (a) Oviparous
In simple words: Birds are classified as oviparous animals, meaning they lay eggs that hatch outside the mother's body. This is a common reproductive strategy for many animal groups.

🎯 Exam Tip: Distinguish between oviparous (egg-laying), viviparous (live birth), and ovoviviparous (eggs hatch inside mother, live birth).

 

Question 15. Having teeth in their mouth What is the scientific name of national bird of India?
(a) Psittacula eupatra
(b) Passer domesticus
(c) Pavo cristatus
(d) Corvus splendens
Answer: (c) Pavo cristatus
In simple words: The scientific name for the national bird of India, the Indian peafowl (peacock), is Pavo cristatus. Birds do not have teeth; instead, they use their beaks and gizzards for processing food.

🎯 Exam Tip: Scientific names are always italicized with the genus capitalized and species lowercase, and they are universal. Also, remember key biological facts like birds not having teeth.

Bio-Diversity RBSE Rajasthan Board Solutions Very Short Answer Type Questions

 

Question 1. According to binomial nomenclature, the scientific name of an organism must consist of two words. These are-
Answer: Genus and species. In binomial nomenclature, a scientific name for any organism is made up of two parts: the first part is the genus name, and the second part is the species name. This system helps in giving a unique, universally recognized name.
In simple words: Scientific names have two parts: the genus and the species.

🎯 Exam Tip: Remember that binomial nomenclature provides a unique, two-part name (genus and species) for every organism, aiding in clear communication among scientists.

 

Question 2. What is characteristic of Angiosperm?
Answer: Seeds are formed in fruits. A key characteristic of angiosperms, also known as flowering plants, is that their seeds are enclosed within a fruit. Fruits develop from the flower's ovary and protect the seeds.
In simple words: Angiosperms are flowering plants, and their main feature is that their seeds grow inside fruits.

🎯 Exam Tip: The presence of flowers and fruits enclosing seeds are the defining characteristics of angiosperms.

 

Question 3. What is classification?
Answer: Study of animal groups on the basis of similarities and differences is called classification. Classification is the process of organizing living things into groups based on their shared features and differences. This helps scientists to study and understand the vast diversity of life.
In simple words: Classification is how we sort living things into groups by looking at what makes them alike and different.

🎯 Exam Tip: Emphasize that classification helps organize biodiversity, making it easier to study relationships and evolution among organisms.

 

Question 4. Give two adaptations in desert plants.
Answer: Desert plants have special features to survive with very little water. First, their leaves are often small, or changed into spines (like in Opuntia) to prevent water loss. Second, their roots usually grow very long and deep to find water underground.
In simple words: Desert plants save water by having tiny leaves or spines, and their roots grow very deep to find water.

🎯 Exam Tip: Focus on water conservation strategies: reduced leaf surface area, waxy cuticles, sunken stomata, and extensive root systems are common desert plant adaptations.

 

Question 6. Classify the plants on the basis of available amount of water.
Answer: Plants are grouped into different types based on how much water is available in their habitat. These groups are: 1. Hydrophytes (grow in water), 2. Mesophytes (grow in moderate water conditions), 3. Xerophytes (grow in dry conditions), and 4. Halophytes (grow in salty water).
In simple words: Plants are put into groups based on how much water they live in: Hydrophytes (lots of water), Mesophytes (normal water), Xerophytes (little water), and Halophytes (salty water).

🎯 Exam Tip: Learn the characteristics of each plant type (hydrophyte, xerophyte, etc.) in relation to water availability and how they adapt.

 

Question 7. Name the animals which have a four-chambered heart.
Answer: Animals belonging to the class Aves (birds) and Mammalia (mammals) both possess a four-chambered heart. This efficient heart structure helps separate oxygenated and deoxygenated blood, which is important for maintaining a constant body temperature.
In simple words: Birds and mammals both have a heart with four chambers.

🎯 Exam Tip: A four-chambered heart is a key adaptation for warm-blooded (homeothermic) animals, allowing for efficient circulation and higher metabolic rates.

 

Question 8. Name the- (a) Largest existing mammal, and (b) Largest mammal on land.
Answer: (a) The largest living mammal is the blue whale, found in the ocean. (b) On land, the largest mammal is the elephant. It is interesting how these largest mammals adapted to very different environments.
In simple words: The blue whale is the biggest mammal alive. The elephant is the biggest mammal that lives on land.

🎯 Exam Tip: Differentiate between overall largest (aquatic) and largest on land when discussing animal size records.

 

Question 9. Which type of animals has no organs?
Answer: Unicellular animals, which are made up of only one cell, do not have complex organs. Their single cell performs all necessary life functions. For multicellular organisms, cells group together to form tissues, then organs.
In simple words: Animals with only one cell do not have organs. Their single cell does all the work.

🎯 Exam Tip: Understand the hierarchy of biological organization: cells -> tissues -> organs -> organ systems. Unicellular organisms operate at the cellular level.

 

Question 10. Name the respiratory organs in the following?
(a) Amoeba
(b) Tapeworm
(c) Crab
Answer:
(a) Amoeba: Respires through its general body surface, absorbing oxygen directly from the water.
(b) Tapeworm: Being an internal parasite, it respires anaerobically (without oxygen) from its host.
(c) Crab: Respires through gills, which are feather-like organs located within their body. The structure of gills helps in efficient gas exchange in aquatic environments.
In simple words: Amoeba breathes through its whole body. Tapeworm breathes without oxygen inside its host. Crab breathes using gills.

🎯 Exam Tip: Respiratory organs vary greatly across different animal phyla, depending on their habitat and metabolic needs (e.g., skin, gills, lungs, tracheae).

 

Question 11. Which class has the largest number of animals?
Answer: The class Insecta, which includes insects, has the largest number of animal species on Earth. They are incredibly diverse and live in almost every habitat, making them very successful.
In simple words: The Insecta group has the most types of animals in the world.

🎯 Exam Tip: Remember that insects dominate animal diversity, making them a crucial group in ecosystems.

 

Question 12. Why is the scientific name of an organism unique?
Answer: A scientific name is unique for each organism because it provides a single, universally accepted way to identify that specific species. This avoids confusion caused by different common names in various languages and regions across the world.
In simple words: A scientific name is special because it's the only name for that living thing, and everyone around the world uses the same name to identify it.

🎯 Exam Tip: Emphasize universality and clarity as the main benefits of unique scientific names in biology.

Bio-Diversity Solutions Short Answer Type Questions

 

Question 1. Which organisms are called primitive and how are they different from so-called advanced organism's?
Answer: Primitive organisms are those that appeared earlier in evolution and have simpler body structures and organization. Advanced organisms developed later and typically have more complex structures and specialized systems. For instance, tiny, single-celled bacteria are primitive, while multi-celled mammals are considered advanced. Similarly, simple algae are primitive plants, but flowering plants (angiosperms) are advanced. In the animal kingdom, fishes are often considered primitive vertebrates compared to birds, which are advanced.
In simple words: Primitive organisms are old and simple, while advanced organisms came later and are more complex. For example, bacteria are primitive, and mammals are advanced.

🎯 Exam Tip: Understanding the concept of primitive versus advanced in biology relates to evolutionary history and increasing complexity in structure and function.

 

Question 2. What is the criterion for classification of organisms belonging to kingdom Monera or Protista?
Answer: Organisms are classified into Monera or Protista based on their cell structure. Monera includes single-celled organisms that lack a true nucleus and other membrane-bound cell parts (prokaryotes). Protista includes single-celled organisms that *do* have a true nucleus and membrane-bound organelles (eukaryotes). This fundamental difference in cellular organization drives their kingdom placement.
In simple words: Monera are tiny living things without a proper nucleus in their cell. Protista are also tiny living things, but they *do* have a proper nucleus.

🎯 Exam Tip: The presence or absence of a well-defined nucleus (prokaryotic vs. eukaryotic) is a fundamental criterion for classifying organisms at the kingdom level.

 

Question 3. Define Classification? Write the aims of classification?
Answer: **Definition of Classification:** Classification is the process of arranging organisms into groups and subgroups based on their shared features and differences.
**Aims of Classification:**
1. To give a clear overview of all plants and animals, helping us understand their diversity.
2. To understand how different groups, like vertebrates and invertebrates, are similar and different from each other.
3. To support the idea that all living things may share a common ancestor, showing evolutionary relationships.
4. To show how different groups of plants are connected to each other, highlighting their evolutionary paths.
In simple words: Classification means putting living things into groups based on what they share and what makes them different. It helps us see all plants and animals, understand their links, and show how they are related.

🎯 Exam Tip: A strong definition of classification and a clear list of its aims are essential for understanding biodiversity and its systematic study.

 

Question 4. Why do we keep both, snake and turtle in the same class?
Answer: Snakes and turtles are both placed in the same class (Reptilia) because they share several key characteristics. Both are cold-blooded, meaning their body temperature changes with their surroundings. They both have scales covering their bodies, breathe using lungs, and lay eggs on land, not in water. These shared features show a common evolutionary lineage.
In simple words: Snakes and turtles are in the same group because they are cold-blooded, have scales, breathe with lungs, and lay their eggs on land.

🎯 Exam Tip: Focus on the shared reptilian characteristics: poikilothermy (cold-blooded), dry scaly skin, lung respiration, and amniotic eggs laid on land.

 

Question 5. Give three examples of the range of variation that you see in life forms around you.
Answer: Life on Earth shows amazing variation. For example:
**Size:** Organisms range from tiny, microscopic bacteria (a few micrometers in size) to giant blue whales (about 30 meters long) and towering redwood trees (about 100 meters tall). This shows an incredible scale.
**Life span:** The duration of life also varies greatly. Some pine trees live for thousands of years, while insects like mosquitoes live only for a few days.
**Appearance:** In terms of looks, some species are colorless and transparent, while others are vibrantly colored, like various birds, butterflies, and attractive plants with colored leaves and flowers.
In simple words: Living things vary a lot in size, how long they live, and how they look. Some are tiny, some are huge. Some live a long time, some for just days. Some are clear, some are very colorful.

🎯 Exam Tip: When illustrating variation, choose distinct examples that clearly highlight the extreme ends of the spectrum for each characteristic (e.g., smallest vs. largest, shortest vs. longest lifespan).

 

Question 6. What do you understand by Crypto- gamae and Phanerogamae? Explain.
Answer: **Cryptogamae:** These are plants where the reproductive organs are hidden or not clearly visible. They reproduce using spores and do not produce seeds or flowers. This group includes thallophytes (like algae), bryophytes (like mosses), and pteridophytes (like ferns). They represent earlier forms of plant life.
**Phanerogamae:** These are plants that have well-developed reproductive organs and produce seeds. They are often called "flowering plants" or "seed plants." This group is divided into gymnosperms (plants with naked seeds) and angiosperms (plants whose seeds are enclosed in fruits).
In simple words: Cryptogamae are plants that hide their reproductive parts and grow from tiny spores, not seeds or flowers. Phanerogamae are plants that have clear reproductive parts and make seeds (like flowering plants).

🎯 Exam Tip: The main distinction between Cryptogamae and Phanerogamae lies in their reproductive strategy: spore-bearing (hidden reproductive organs) versus seed-bearing (visible reproductive organs).

 

Question 7. Explain the basis for grouping organisms into five kingdoms?
Answer: R.H. Whittaker proposed the five-kingdom classification system based on several key characteristics. The main criteria he used were:
1. **Cell Structure:** This considers whether the organism's cells are prokaryotic (lacking a true nucleus) or eukaryotic (possessing a true nucleus).
2. **Mode of Nutrition:** This refers to how the organism obtains its food, such as photosynthesis (making food, like plants), absorption (taking in nutrients from the surroundings, like fungi), or ingestion (eating food, like animals).
3. **Body Organization:** This criterion evaluates whether the organism is unicellular (single-celled) or multicellular (composed of many cells).
These factors help categorize life into Monera, Protista, Fungi, Plantae, and Animalia, showing their evolutionary relationships.
The five kingdom classification can be represented structurally as follows:
Organisms
\( \downarrow \)

• Prokaryotes \( \implies \) Monera
• Eukaryotes
  • \( \downarrow \) Unicellular \( \implies \) Protista
  • \( \downarrow \) Multicellular
    • \( \downarrow \) With cell wall
      • \( \downarrow \) Do not perform photosynthesis \( \implies \) Fungi
      • \( \downarrow \) Able to perform photosynthesis \( \implies \) Plantae
    • \( \downarrow \) Without cell wall \( \implies \) Animalia

In simple words: Whittaker grouped living things into five kingdoms based on three things: if their cells have a nucleus, how they eat food, and if they are made of one cell or many cells.

🎯 Exam Tip: Memorize Whittaker's three primary criteria (cell structure, mode of nutrition, body organization) as the foundation for the five-kingdom classification system.

 

Question 8. Write the characteristics of phylum Annelida with examples.
Answer: Annelida is a phylum of segmented worms. Their key characteristics include:
1. **Segmented Body:** Their bodies are divided into many similar segments, giving them a ring-like appearance.
2. **Bilateral Symmetry:** They have a body that can be divided into two mirror-image halves.
3. **True Coelom:** They possess a true body cavity (coelom) which is filled with fluid.
4. **Respiration:** Many annelids, like earthworms, respire through their moist skin, absorbing oxygen directly.
5. **Locomotion:** They move using small bristles (setae) or muscular contractions of their segmented bodies.
Examples include Nereis, Pheretima (earthworm), and Hirudinaria (leech). Annelids play vital roles in soil aeration and nutrient cycling.
In simple words: Annelids are worms with bodies made of many rings or segments. They are symmetrical, have an internal body space, and many breathe through their skin. Earthworms and leeches are common examples of annelids.

🎯 Exam Tip: Remember "segmented body" and "moist skin respiration" as crucial distinguishing features for Annelida, along with their bilateral symmetry and true coelom.

 

Question 9. Write any three concrete examples of such characteristics that are used for hierarchical classification.
Answer: Three concrete characteristics used for hierarchical classification are:
1. **Cell Structure:** This includes whether the cells are prokaryotic (without a true nucleus) or eukaryotic (with a true nucleus), and the presence or absence of a cell wall.
2. **Mode of Nutrition:** How organisms obtain their food, such as photosynthesis (plants), absorption (fungi), or ingestion (animals).
3. **Body Organization:** Whether the organism is unicellular (single-celled) or multicellular (many cells), and its level of tissue and organ differentiation.
These characteristics help scientists place organisms into different taxonomic ranks like kingdoms, phyla, and classes.
The hierarchical classification system follows this order:
Kingdom
\( \downarrow \)
Phylum (for animals)/Division (for plants)
\( \downarrow \)
Class
\( \downarrow \)
Order
\( \downarrow \)
Family
\( \downarrow \)
Genus
\( \downarrow \)
Species
Species is the smallest and basic unit of classification.
In simple words: Three things used to classify living things are: how their cells are built (with or without a nucleus, cell wall), how they get food (make their own, absorb, or eat), and if they are one-celled or many-celled.

🎯 Exam Tip: Clearly distinguish between categories of classification (e.g., Kingdom, Phylum) and the *characteristics* used to define those categories (e.g., cell type, nutrition, body plan).

 

Question 10. Name the invertebrate groups and their role in ecosystem?
Answer: Invertebrates are animals without a backbone, making up the vast majority of animal species on Earth. Major invertebrate groups include Porifera (sponges), Coelenterata (jellyfish, corals), Platyhelminthes (flatworms), Nematoda (roundworms), Annelida (segmented worms), Arthropods (insects, spiders, crustaceans), Mollusca (snails, clams, octopuses), and Echinodermata (starfish, sea urchins).
Invertebrates play a vital role in keeping the ecosystem healthy in the following ways:
1. **Decomposition:** They help break down dead plants and animals, recycling nutrients back into the soil and water. This is essential for ecosystem nutrient cycles.
2. **Pollination:** Many insects are crucial for pollinating flowers, which is essential for the reproduction of many plants and thus for fruit and seed production.
3. **Soil Health:** Some, like earthworms, loosen the soil, improve its structure, and distribute seeds, aiding plant growth and water penetration.
In simple words: Invertebrates are animals without a backbone, like worms, insects, and crabs. They are very important because they help break down dead things, pollinate flowers, and make the soil healthy.

🎯 Exam Tip: Be able to list several invertebrate phyla and provide at least two significant ecological roles (e.g., decomposers, pollinators, food source, pest control).

Bio-Diversity Rajasthan Board Long Answer Type Questions

 

Question 1. Describe the classification of plants.
Answer: Plants are classified based on several features, starting with the presence or absence of clearly defined body parts like roots, stems, and leaves.
The first level of classification groups plants based on whether their body is well-differentiated. Algae (Thallophyta) are separated because of their simple, undifferentiated body (thalloid plant body).
The next level distinguishes plants by whether they have vascular tissues (specialized tissues for transporting water and nutrients). This character separates Bryophytes (like mosses, which lack true vascular tissue) from the rest of the plants.
Further classification is based on the ability to bear seeds. Pteridophytes (like ferns) reproduce using spores and do not produce seeds.
Finally, the groups of seed-bearing plants are formed on the basis of whether seeds are naked or enclosed within fruits. Gymnosperms (like pines) have naked seeds, meaning they are not enclosed in an ovary. In contrast, Angiosperms (flowering plants) bear seeds enclosed within a fruit.
Therefore, Kingdom Plantae consists of Thallophyta, Bryophyta, Pteridophyta, Gymnosperms, and Angiosperms, reflecting increasing complexity.
In simple words: Plants are sorted into groups based on if they have clear body parts, if they have tubes for water, and if they make seeds. Some plants, like algae, are simple. Others, like mosses, are a bit more complex. Ferns make spores. Plants with seeds are either Gymnosperms (naked seeds) or Angiosperms (seeds in fruits).

🎯 Exam Tip: For plant classification, trace the evolutionary advancements: from undifferentiated body to differentiated, from non-vascular to vascular, and from spore-bearing to seed-bearing (naked vs. enclosed).

 

Question 2. Define characteristics of Chordata and its classes?
Answer:
**Characteristics of Chordata:**
- Animals in the phylum Chordata have a notochord, a flexible rod that supports the body, at some stage of their life.
- They also possess a dorsal hollow nerve cord located along the middle of their back.
- Pharyngeal gill slits (or clefts) are present in their throat region at some point in their development.
- The heart is situated on the ventral (front) side of the body.
- They have a closed circulatory system, meaning blood flows only within vessels. The efficient design of their circulatory system is key for transporting nutrients and oxygen effectively.
**Classification of Plants based on vascular tissue, seeds, and cotyledons:**
Thallophyta
\( \downarrow \)
Vascular tissue absent
\( \downarrow \)
Bryophyta
\( \downarrow \)
Vascular tissue present
\( \downarrow \)
Do not produce seeds
\( \downarrow \)
Pteridophyta
\( \downarrow \)
Produce seeds (Phanerogams)
\( \downarrow \)
Seeds naked
\( \downarrow \)
Gymnosperms
\( \downarrow \)
Seeds inside fruits
\( \downarrow \)
Angiosperms
\( \downarrow \)

• Seeds with two cotyledons (Dicots)
• Seeds with one cotyledon (Monocots)

In simple words: Chordates have a flexible rod (notochord), a nerve cord on their back, gill slits in their throat, a heart in the front, and blood that stays in tubes. The diagram shows how plants are grouped based on whether they have water tubes, make seeds, and how many seed leaves they have.

🎯 Exam Tip: Focus on the four distinguishing features of Chordates. For plant classification, remember the hierarchy from simple to complex: Thallophyta, Bryophyta, Pteridophyta, Gymnosperms, and Angiosperms.

 

Question 2 (continued). Classes of Chordata:
Answer: The sub-kingdom Chordata is classified into five main classes:
**1. Class-Pisces:** This class includes all types of fish and other aquatic animals. Fishes are cold-blooded and live in water. Their bodies are streamlined, with a head, trunk, and tail, and are typically covered with scales. Fins help them swim, and their skeleton can be cartilage or bone. Respiration occurs through gills, and they have a two-chambered heart. Examples are: Dogfish, Rohu, Seahorse, Stingray, etc.
**3. Class-Reptilia:** This class includes reptiles like snakes, tortoises, and lizards. Reptiles move by crawling on the ground. They breathe using lungs, and their bodies are covered with dry scales. Their heart has two upper chambers (auricles) and a ventricle that is often partly divided. Reptiles are cold-blooded and lay eggs on land. Examples include Tortoise, Lizard, and Viper.
**4. Class - Aves:** This class comprises birds, which are adapted for flight. Their front limbs are modified into wings for flying. Their bodies are streamlined and covered with feathers, divided into a head, neck, chest, and tail. Birds have horny beaks instead of teeth and hollow bones, making them light for flight. They are warm-blooded and their heart is fully four-chambered. Examples include pigeon, crow, and sparrow.
**5. Class - Mammalia:** This class includes mammals, like kangaroos, humans, and bats. A defining feature is the presence of mammary glands in females, which produce milk to feed their young. Mammals have hair on their bodies and external ears (pinnae). They are warm-blooded, breathe with lungs, and have a fully four-chambered heart (two auricles and two ventricles). Most mammals give birth to live young (viviparous).
In simple words: Fish (Pisces) are cold-blooded, aquatic, with gills. Reptiles crawl, have scales, and lay eggs on land. Birds (Aves) fly with wings, have feathers, and are warm-blooded. Mammals feed milk to young, have hair, and are warm-blooded.

🎯 Exam Tip: For each class, memorize 2-3 unique characteristics and at least two examples to clearly differentiate them.

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