Chapter 2

S.No	Pair	Definition	Two Differences	Examples
i	Bryophytes and Pteridophytes	Bryophytes are non-vascular plants; Pteridophytes are seedless vascular plants.	Bryophytes lack vascular tissue; Pteridophytes have it. Bryophytes lack true roots; Pteridophytes have true roots, stems, and leaves.	Moss, Liverwort — Fern, Selaginella
ii	Algae and Bryophytes	Algae are simple, mostly aquatic photosynthetic organisms; Bryophytes are land-based non-vascular plants.	Algae can be unicellular or multicellular; Bryophytes are only multicellular. Algae lack roots and leaves; Bryophytes have primitive ones.	Spirogyra, Chlamydomonas — Moss, Riccia
iii	Gymnosperms and Angiosperms	Gymnosperms are plants with naked seeds; Angiosperms are flowering plants with enclosed seeds.	Gymnosperms do not form fruits; Angiosperms form fruits. Gymnosperms lack flowers; Angiosperms have flowers.	Pine, Cycas — Mango, Rose
iv	Monocots and Dicots	Monocots have one seed leaf (cotyledon); Dicots have two seed leaves.	Monocots have parallel venation; Dicots have reticulate venation. Monocots have fibrous roots; Dicots have a taproot.	Maize, Rice — Bean, Neem
v	Vascular and Non-vascular Plants	Vascular plants have xylem and phloem; Non-vascular plants do not.	Vascular plants have true roots and stems; Non-vascular do not. Vascular plants transport nutrients internally; Non-vascular absorb externally.	Fern, Mango — Moss, Liverwort
vi	Seahorse and Horse	Seahorse is a small marine fish; Horse is a large terrestrial mammal.	Seahorse breathes through gills; Horse uses lungs. Seahorse lays eggs; Horse gives birth to live young.	Hippocampus — Equus
vii	Crayfish and Starfish	Crayfish is a freshwater crustacean; Starfish is a marine echinoderm.	Crayfish has a segmented body and exoskeleton; Starfish has radial symmetry and endoskeleton. Crayfish is bilateral; Starfish is radial.	Cambarus — Asterias
viii	Moss and Club Moss	Moss is a non-vascular bryophyte; Club moss is a vascular pteridophyte.	Moss lacks vascular tissue; Club moss has it. Moss has no true leaves; Club moss has microphylls.	Funaria — Lycopodium
ix	Pine and Mango	Pine is a gymnosperm; Mango is an angiosperm.	Pine has naked seeds; Mango has enclosed seeds. Pine does not produce flowers; Mango does.	Pinus — Mangifera indica
x	Ascaris and Taenia	Ascaris is a roundworm (nematode); Taenia is a flatworm (cestode).	Ascaris is cylindrical with a complete digestive tract; Taenia is flat and lacks a digestive tract. Ascaris is free in intestine; Taenia attaches to the wall.	Ascaris lumbricoides — Taenia solium
xi	Invertebrates and Vertebrates	Invertebrates lack a backbone; Vertebrates have a backbone.	Invertebrates have simple body systems; Vertebrates are more complex. Invertebrates may have exoskeleton; Vertebrates have endoskeleton.	Insect, Jellyfish — Fish, Mammal
xii	Bird and Bat	Bird is a feathered, egg-laying avian; Bat is a furred, live-bearing mammal.	Bird has feathers and lays eggs; Bat has fur and gives birth. Birds have hollow bones; Bats have solid bones.	Pigeon — Fruit Bat
xiii	Male Ascaris and Female Ascaris	Male and female are the two sexes of the roundworm Ascaris.	Male is shorter and has curved tail; Female is longer with straight tail. Male has spicules; Female lacks spicules.	Male (smaller) — Female (larger) Ascaris

3.very short questions

a. Who proposed the five-kingdom system of classification?
R.H. Whittaker proposed the five-kingdom system of classification in 1969. The five kingdoms are: Monera, Protista, Fungi, Plantae, and Animalia.

b. Write the divisions of the kingdom Plantae.
The kingdom Plantae is divided into the following five divisions:

Thallophyta – Simple plants like algae, fungi, and lichens.
Bryophyta – Non-vascular plants like mosses and liverworts.
Pteridophyta – Vascular, seedless plants like ferns.
Gymnosperms – Seed-bearing, non-flowering plants like pine and fir trees.
Angiosperms – Flowering plants that produce seeds enclosed within fruits.

c. What are angiosperms?
Angiosperms are plants that produce flowers and bear seeds within fruits. They are the most diverse group of plants and include trees, shrubs, and herbs. Examples include roses, mangoes, and wheat.

d. Name any two non-vascular plants.
Two examples of non-vascular plants are moss and liverwort. These plants lack vascular tissues like xylem and phloem, and they absorb water directly through their surfaces.

e. The spider has four pairs of jointed legs. Which phylum does it belong to?
The spider belongs to the phylum Arthropoda. This phylum is characterized by animals with segmented bodies, exoskeletons, and jointed limbs. Spiders specifically belong to the class Arachnida.

f. What are chordates?
Chordates are animals that, at some stage of their life cycle, possess a notochord, a dorsal nerve cord, pharyngeal slits, and a post-anal tail. All vertebrates (including fish, amphibians, reptiles, birds, and mammals) are chordates.

g. What is evolution?
Evolution is the process by which populations of organisms change over generations through variations in traits, which can lead to the formation of new species. It is driven by natural selection, mutation, genetic drift, and gene flow.

h. Name any two bryophytes.
Two examples of bryophytes are moss and funaria. Bryophytes are non-vascular plants that typically grow in damp environments and have structures that are similar to roots, stems, and leaves, but are simpler.

i. Define diploblastic.
Diploblastic refers to organisms that have two primary germ layers: the outer ectoderm and the inner endoderm. These organisms do not have a mesoderm (middle layer). Examples include cnidarians like jellyfish and corals.

j. Define hermaphrodites.
Hermaphrodites are organisms that possess both male and female reproductive organs. Some species, such as earthworms and many snails, can reproduce sexually with any other member of their species because both individuals have the necessary reproductive organs.

k. Name five classes of vertebrates.
The five classes of vertebrates are:

Pisces (Fish)
Amphibia (Amphibians)
Reptilia (Reptiles)
Aves (Birds)
Mammalia (Mammals)

l. Name any two animals which have pneumatic bones.
Two examples of animals with pneumatic bones (hollow bones that reduce body weight) are pigeons and owls. These animals need lightweight skeletons for efficient flight.

m. Write the locomotory organs of an earthworm and a starfish.
The locomotory organs are:

Earthworm – Setae (bristles) on its body segments help it move through soil.
Starfish – Tube feet that extend and contract to move the body along surfaces.

n. What are trimerous flowers?
Trimerous flowers are flowers that have floral parts in multiples of three. This is characteristic of monocot plants such as lilies and grasses.

o. Define monoecious and dioecious.

Monoecious refers to plants that have both male and female reproductive organs on the same individual (e.g., corn and cucumber).
Dioecious refers to plants where male and female reproductive organs are on separate individuals (e.g., holly and kiwi).

p. What are mammals?
Mammals are warm-blooded vertebrates characterized by the presence of hair or fur, and the ability to produce milk to nourish their young. Examples include humans, elephants, and whales.

q. Write the functions of tentacles.
Tentacles are flexible, elongated structures found in some animals. They are used for:

Locomotion (e.g., octopuses use them to move).
Capturing prey (e.g., jellyfish use tentacles to trap small animals).
Sensory functions (e.g., tentacles of some animals sense their environment).

r. Which group of animals has an incomplete alimentary canal?
Platyhelminthes (flatworms) have an incomplete alimentary canal, meaning they have only one opening for both ingestion and egestion, unlike most animals that have separate openings for food intake and waste removal.

s. Where are sponges found?
Sponges are aquatic organisms, primarily found in marine environments, though some live in freshwater. They are commonly found attached to rocks, coral reefs, or the ocean floor.

t. Define exoskeleton and endoskeleton.

An exoskeleton is a hard outer covering that provides support and protection to the body (e.g., insects and crustaceans).
An endoskeleton is an internal skeleton that provides structural support and protection for the body (e.g., in humans and other vertebrates).

4. answer the following

Here are the detailed paragraph-style answers to the questions:

a. Enlist the five kingdoms of classification.
The five-kingdom system of classification, proposed by R.H. Whittaker in 1969, divides all living organisms into five broad categories based on certain similarities and differences. These kingdoms are:

Monera – This kingdom includes unicellular organisms that lack a true nucleus, such as bacteria and cyanobacteria. They are prokaryotic, meaning their cells do not have membrane-bound organelles.
Protista – Protists are mostly unicellular eukaryotic organisms, which means their cells have a nucleus. This kingdom includes algae, protozoa, and slime molds.
Fungi – Fungi are non-photosynthetic organisms that are usually multicellular and include molds, yeasts, and mushrooms. They absorb nutrients through external digestion and are important decomposers in ecosystems.
Plantae – The plant kingdom includes multicellular, autotrophic organisms that carry out photosynthesis to produce their food. Plants have cell walls made of cellulose and are usually fixed in one place (sessile).
Animalia – Animals are multicellular, heterotrophic organisms that lack cell walls. They are capable of movement at some point in their life cycle and have specialized nervous and sensory systems.

b. On what basis are living organisms divided in the five-kingdom system of classification?
In the five-kingdom system of classification, living organisms are divided based on several factors such as cell structure, mode of nutrition, body organization, and reproductive methods.

Cell Structure: Organisms are classified as prokaryotic (lacking a true nucleus) or eukaryotic (with a true nucleus and membrane-bound organelles). This is a key distinction that separates organisms like bacteria (Monera) from others such as plants, fungi, and animals (all eukaryotic).
Mode of Nutrition: Organisms are classified based on how they obtain food. For instance, plants are autotrophic, meaning they produce their own food through photosynthesis, while animals are heterotrophic, relying on other organisms for food.
Body Organization: Organisms can be unicellular (like bacteria and protozoa) or multicellular (like plants and animals).
Reproduction: Organisms also differ in their modes of reproduction, whether sexual or asexual. For example, fungi often reproduce through spores, while animals typically reproduce sexually.

c. What are the different levels of classification?
The classification of organisms follows a hierarchical system that ranges from broader categories to more specific ones. This system is called taxonomy. The different levels of classification are as follows:

Domain: This is the broadest level of classification, which groups organisms into three domains: Archaea, Bacteria, and Eukarya.
Kingdom: This level divides life into major groups such as animals, plants, fungi, etc.
Phylum: Within each kingdom, organisms are further divided into phyla based on their general body plan or structure.
Class: Phyla are further divided into classes.
Order: Each class is divided into orders, grouping organisms that share more specific characteristics.
Family: Orders are broken down into families.
Genus: Families are divided into genera (plural of genus), which are groups of species that are closely related.
Species: This is the most specific level of classification, representing individual organisms that can interbreed and produce fertile offspring.

d. Enlist any two characteristics of algae.
Algae are simple, autotrophic organisms that can perform photosynthesis. They are classified into different groups based on their pigmentation and other features. Two main characteristics of algae are:

Photosynthetic Ability: Algae are primarily photosynthetic organisms, meaning they can synthesize their own food by converting light energy into chemical energy. This makes them crucial producers in aquatic ecosystems.
Aquatic Habitat: Algae are mostly found in aquatic environments, whether freshwater or marine. Some can also live in moist terrestrial habitats, but they are predominantly aquatic.

e. Why are bryophytes called amphibian plants?
Bryophytes are often called "amphibian plants" because, like amphibians, they live in both aquatic and terrestrial environments. Bryophytes, such as mosses and liverworts, require water for reproduction, as their sperm must swim to reach the egg for fertilization. However, they can survive on land, though they thrive in moist habitats. This adaptation makes them similar to amphibians, which can live in water and on land but are dependent on moisture for breeding.

f. Mustard is advanced than the pine, why?
Mustard, an angiosperm (flowering plant), is considered more advanced than pine, a gymnosperm, due to several key characteristics:

Flowers and Pollination: Mustard produces flowers, which are more specialized for pollination by insects, birds, or wind. Pine, on the other hand, produces cones and relies on wind for pollination.
Seed Enclosure: Mustard seeds are enclosed within fruits, which help protect them and assist in seed dispersal. In contrast, pine seeds are exposed on cone scales, making them less protected.
Vascular Tissue: Angiosperms like mustard have more advanced vascular tissue, which supports better water and nutrient transport, enhancing growth and survival in diverse environments.

g. Write any two similarities between Aves and Reptilia.
Despite their differences, Aves (birds) and Reptilia (reptiles) share some common features:

Vertebrates: Both Aves and Reptilia are vertebrates, meaning they have a backbone made of vertebrae.
Eggs: Both groups reproduce by laying eggs, which have a protective outer shell. While the eggs of birds are hard, those of reptiles are typically leathery.

h. Write any two characteristics of Echinodermata.
Echinodermata is a diverse group of marine animals, such as starfish, sea urchins, and sea cucumbers, that share several key characteristics:

Radial Symmetry: Echinoderms exhibit radial symmetry, especially as adults, meaning their bodies are arranged around a central axis.
Calcareous Exoskeleton: Echinoderms possess a hard, calcareous exoskeleton made of plates or ossicles, which provides structural support and protection.

i. Write any two common features that make Aves different from Mammalia.
Aves (birds) and Mammalia (mammals) belong to different classes of vertebrates, and they differ in several ways:

Feathers vs. Hair: Birds (Aves) are characterized by the presence of feathers, which help with flight and thermoregulation, while mammals have hair or fur.
Eggs vs. Live Birth: Most birds lay eggs that hatch externally, whereas most mammals give live birth (with the exception of monotremes, like platypus, which lay eggs).

j. Why are frog and toad called cold-blooded animals?
Frogs and toads are considered cold-blooded, or ectothermic, because their body temperature depends on the external environment rather than being regulated internally. They are unable to generate enough heat to maintain a constant body temperature, so they rely on environmental heat sources to warm up and become active, and seek shade or water to cool down.

k. Classify fern and cycas.

Organism	Kingdom	Phyla	Class	Type	Characteristics
Fern	Plantae	Pteridophyta	-	Seedless Vascular	True leaves (fronds), stems, and roots; reproduces via spores; thrives in damp areas.
Cycas	Plantae	Gymnosperms	Cycadopsida	Seed-bearing	Exposed seeds on cones, no flowers, vascular tissue, found in tropical regions.

l. Write any two animals which belong to the following:

Annelida:
1. Earthworm
2. Leech
Mollusca:
1. Snail
2. Octopus

5 long question answer

a. Write the importance of classification.
Classification is an essential process in biology because it provides a structured system to categorize the vast diversity of living organisms based on their shared characteristics. This system allows scientists to systematically study organisms and understand the relationships between them. Some of the key points about the importance of classification are as follows:

Organizes Biological Diversity: The primary importance of classification lies in its ability to organize the immense variety of living organisms into manageable categories. It helps to reduce the complexity of the natural world by grouping organisms with similar characteristics together.
Identification and Nomenclature: Classification provides a method for naming organisms (binomial nomenclature), allowing for universal identification and eliminating confusion caused by common names. Scientific names are standardized across languages, ensuring global consistency in referring to organisms.
Study of Evolutionary Relationships: Classification also helps to trace the evolutionary history of organisms. By grouping organisms based on shared ancestry, it allows scientists to study evolutionary trends and understand how different species have evolved over time.
Environmental Understanding: Classification helps in understanding the role of each organism within ecosystems. By grouping organisms according to shared traits, we can study their functions and ecological interactions more effectively.
Conservation: Proper classification helps identify species that are rare or endangered, and this information is crucial for conservation efforts. Understanding the relationships between species can lead to better management of biodiversity.

b. Enlist the characteristics of the kingdom Plantae.
The kingdom Plantae includes all multicellular, eukaryotic organisms that are primarily autotrophic, meaning they produce their own food through photosynthesis. The characteristics of Plantae include:

Multicellular Organization: Plants are made up of multiple cells, each containing a true nucleus and other organelles.
Cell Walls: The cells of plants have rigid cell walls made of cellulose, providing structural support and protection.
Autotrophic Nutrition: Plants are autotrophic, meaning they can produce their own food through photosynthesis, using sunlight, carbon dioxide, and water.
Chlorophyll: Plants contain chlorophyll, a pigment that allows them to capture light energy for photosynthesis.
Vascular Tissue: Most plants have vascular tissues, including xylem and phloem, which transport water, nutrients, and sugars throughout the plant.
Reproduction: Plants reproduce both sexually and asexually. Sexual reproduction occurs through the formation of flowers (in angiosperms) or cones (in gymnosperms), while asexual reproduction occurs through methods like budding, fragmentation, or spore formation.
Sessile Nature: Plants are usually fixed in one location (sessile), meaning they do not move.
Growth: Plants exhibit indeterminate growth, meaning they can grow continuously throughout their lives.

c. Which phylum includes parasitic animals? Give one example and one character.
The phylum Nematoda includes parasitic animals, such as Ascaris.

Example: Ascaris lumbricoides (a parasitic roundworm) is a common parasitic nematode.
Character: Nematodes are elongated, cylindrical worms that have a tough, flexible cuticle and a complete digestive system with a mouth and anus. They are often parasitic, living inside the intestines of animals or humans, causing diseases like ascariasis.

d. Explain how the animals under Vertebrata are classified into further subgroups.
The Vertebrata subphylum is divided into five main classes, each with unique characteristics that distinguish them from one another. The classification is based on factors such as body structure, type of respiration, and reproduction:

Fish (Pisces): Fish are cold-blooded animals that live in water. They have gills for respiration and fins for swimming. Fish have a streamlined body and are adapted to aquatic life. They lay eggs, and their young develop in water. Example: Goldfish.
Amphibians (Amphibia): Amphibians are cold-blooded vertebrates that live both in water and on land. They undergo metamorphosis, starting as aquatic larvae (e.g., tadpoles) and then transforming into adult forms. Amphibians breathe through both gills (as larvae) and lungs (as adults). Example: Frog.
Reptiles (Reptilia): Reptiles are cold-blooded animals with dry, scaly skin. They breathe through lungs and lay eggs with leathery shells. Reptiles have a more advanced structure compared to amphibians, and they can live entirely on land. Example: Snake.
Birds (Aves): Birds are warm-blooded, feathered animals that are capable of flight. They have beaks, lay hard-shelled eggs, and breathe through lungs. Birds have highly specialized respiratory and circulatory systems to support high-energy activities like flight. Example: Eagle.
Mammals (Mammalia): Mammals are warm-blooded vertebrates that have hair or fur and produce milk through mammary glands to nourish their young. They give live birth (with some exceptions like monotremes, which lay eggs) and have a high metabolic rate. Example: Lion.

e. What are the major divisions of Plantae? What is the basis for these divisions?
The major divisions of the kingdom Plantae are:

Bryophytes: These are non-vascular plants that reproduce through spores rather than seeds. They do not have specialized tissues like xylem and phloem for transporting water and nutrients. Bryophytes thrive in moist environments. Example: Moss.
Pteridophytes: These plants have vascular tissue and reproduce via spores. They have true roots, stems, and leaves, but they do not produce seeds. They require a moist environment for spore germination. Example: Fern.
Gymnosperms: Gymnosperms are seed-producing plants, but their seeds are exposed on cone scales rather than being enclosed in a fruit. They are primarily cone-bearing trees and are often evergreen. Example: Pine tree.
Angiosperms: Angiosperms are the most advanced group of plants. They produce seeds enclosed within fruits and flowers. The seeds develop after fertilization in the flowers, which are pollinated by various agents, including wind, insects, and animals. Example: Rose.

The basis for these divisions includes differences in their vascular system, mode of reproduction, and the presence of seeds or spores. The evolution of seeds in gymnosperms and angiosperms marks a key step in the advancement of plant life, allowing them to colonize a variety of environments.

f. Write any four characteristics of the phylum Echinodermata.
Echinoderms are marine animals known for their distinctive features. Four key characteristics include:

Radial Symmetry: Adult echinoderms exhibit radial symmetry, meaning their body parts are arranged symmetrically around a central axis. This type of symmetry is evident in their star-shaped body plans.
Endoskeleton: They possess a hard, internal skeleton made of calcareous plates or ossicles. This provides support and protection.
Water Vascular System: Echinoderms have a unique water vascular system that aids in locomotion, feeding, and respiration. It consists of a network of fluid-filled canals and tube feet.
Regenerative Ability: Many echinoderms have the ability to regenerate lost body parts. For instance, starfish can regenerate lost arms.

g. How are evolution and classification related to each other?
Evolution and classification are closely related because classification systems are based on evolutionary relationships between organisms. The process of evolution explains how species change over time due to natural selection and adaptation to their environment. As species evolve, they acquire new characteristics that make them distinct from their ancestors. Classification reflects these evolutionary changes by grouping organisms with common ancestors into categories. Taxonomy, the science of classification, uses evolutionary history to define groups, with closely related species placed together in the same genus or family. New evolutionary discoveries often lead to revisions in classification systems as scientists gain a deeper understanding of evolutionary relationships.

h. Enlist any three features of reptiles.
Reptiles are a diverse group of cold-blooded animals that share several important features:

Scaly Skin: Reptiles have dry, scaly skin that prevents water loss and provides protection. This adaptation allows them to live in dry environments.
Lungs for Respiration: Unlike amphibians, which can breathe through both their skin and lungs, reptiles exclusively breathe through lungs throughout their life.
Eggs with Leathery Shells: Reptiles lay eggs with leathery, rather than hard, shells. These eggs are resistant to desiccation and can be laid in dry environments.

Here are the extended answers for the rest of your questions:

i. Name the classes of vertebrates and give one example for each.

Vertebrates are classified into five major classes based on their physical characteristics and habitat. These are:

Pisces – Aquatic animals that breathe through gills and move with fins.
Example: Rohu
Amphibia – Animals that can live both in water and on land; they breathe through lungs and moist skin.
Example: Frog
Reptilia – Cold-blooded animals with dry, scaly skin and lungs for breathing.
Example: Lizard
Aves – Warm-blooded animals with feathers, beaks, and wings; most can fly.
Example: Pigeon
Mammalia – Animals that have mammary glands to feed young ones and a body covered with hair.
Example: Human

j. Enlist four characteristics of Mammalia.

Mammary Glands: Female mammals have glands that produce milk to feed their babies.
Hair or Fur: Their bodies are covered with hair or fur for protection and temperature regulation.
Warm-Blooded: Mammals can maintain a constant body temperature internally.
Give Birth to Young Ones: Most mammals give birth to live young ones (except a few egg-laying mammals like the platypus).

k. What are vertebrates? Mention their characteristics.

Definition:
Vertebrates are animals that have a backbone or spinal column. They belong to the subphylum Vertebrata under the phylum Chordata.

Characteristics of Vertebrates:

Internal Skeleton: They have an endoskeleton made of bone or cartilage.
Backbone: A vertebral column protects the spinal cord.
Complex Organs: They have well-developed organs and systems, including a brain and a closed circulatory system.
Bilateral Symmetry: Their bodies are symmetrical on both sides.
Closed Circulatory System: Blood flows through closed vessels, and they have a multi-chambered heart.

l. Write any two animals which belong to the following:

Annelida:
1. Earthworm: A segmented worm that plays a crucial role in soil aeration and nutrient recycling.
2. Leech: Known for their parasitic or carnivorous feeding habits, often used in medicinal applications.
Mollusca:
1. Snail: A soft-bodied animal with a coiled shell, found in terrestrial and aquatic environments.
2. Octopus: A marine animal with eight arms, known for its intelligence and ability to camouflage.

m. Identify the animals on the basis of their salient features and write one more character of each.

The body is covered with waterproof scales and it respires through gills: This describes Fish (e.g., Goldfish).
- Additional character: Fish have fins for locomotion and are adapted to aquatic life.
The body is covered with hair and it can fly: This describes Bats (a type of Mammal).
- Additional character: Bats are the only mammals capable of true flight and have echolocation to navigate in the dark.
The body is covered with spiny skin and it moves with its tube feet: This describes Starfish (a type of Echinoderm).
- Additional character: Starfish can regenerate lost arms, a notable ability among echinoderms.
Respiration takes place through the lungs and locomotion with the help of flippers: This describes Seal (a type of Mammal).
- Additional character: Seals are excellent swimmers, using their flippers to propel through water.

n. Write a comparative account of classes of subphylum Vertebrata under the following:

Mode of Nutrition:
- Fish: Most are carnivorous (eating smaller fish or invertebrates) or herbivorous.
- Amphibians: Typically carnivorous as adults, feeding on insects, worms, etc.
- Reptiles: Carnivorous or herbivorous, depending on the species (e.g., snakes are carnivores, while tortoises are herbivores).
- Birds: Omnivorous, herbivorous, or carnivorous (depends on the species). They often feed on seeds, fruits, insects, or other animals.
- Mammals: Varies widely from carnivores (lions) to herbivores (cows) and omnivores (humans).
Mode of Respiration:
- Fish: Respire through gills, extracting oxygen from water.
- Amphibians: Have both gills (in larval form) and lungs (as adults).
- Reptiles: Use lungs for respiration throughout their life.
- Birds: Respire through lungs with a highly efficient system involving air sacs for continuous airflow.
- Mammals: Respire through lungs, with a diaphragm to assist in breathing.
Mode of Reproduction:
- Fish: Typically external fertilization, with eggs being laid in water.
- Amphibians: External fertilization in most species; eggs are laid in water.
- Reptiles: Internal fertilization; eggs are laid with leathery shells.
- Birds: Internal fertilization; eggs are laid with hard shells.
- Mammals: Internal fertilization; most give live birth, with exceptions (monotremes like platypuses lay eggs).

o. Classify the following with any one distinguishing character:

Organism	Phylum	Class/Type	One Distinguishing Character
Pine	Tracheophyta	Gymnosperm	Has exposed seeds in cones
Whale	Chordata	Mammal	Warm-blooded with live birth and mammary glands
Volvox	Thallophyta	Algae	Colonial and autotrophic with chlorophyll
Moss	Bryophyta	Non-vascular plant	Reproduces by spores
Fern	Pteridophyta	Vascular plant	Reproduces by spores
Pea	Tracheophyta	Angiosperm	Flowering plant with enclosed seeds in fruit
Bamboo	Tracheophyta	Angiosperm	Woody flowering plant with hollow stems
Bat	Chordata	Mammal	Has wings and can fly
Crocodile	Chordata	Reptile	Lays eggs with leathery shells
Duck	Chordata	Bird	Has feathers and webbed feet
Mustard	Tracheophyta	Angiosperm	Seeds enclosed in fruits
Spongilla	Porifera	Poriferan	Asymmetrical body with pores for filtering water
Sea Anemone	Cnidaria	Cnidarian	Radially symmetrical with stinging cells
Ascaris	Nematoda	Roundworm	Cylindrical body and parasitic nature
Liver Fluke	Platyhelminthes	Flatworm	Flat, bilaterally symmetrical body
Snail	Mollusca	Mollusc	Soft body with coiled shell
Sea Urchin	Echinodermata	Echinoderm	Spiny skin with radial symmetry
Wall Lizard	Chordata	Reptile	Cold-blooded with scaly skin
Butterfly	Arthropoda	Insect	Metamorphic life cycle with wings
Octopus	Mollusca	Mollusc	Eight tentacles and high intelligence

p. Which organisms are called primitive and how are they different from advanced organisms?
Primitive organisms are those that have relatively simple body structures and exhibit fewer specialized functions. These organisms often resemble early forms of life in evolutionary terms. They tend to be less adapted to diverse environments. Examples of primitive organisms include bacteria, sponges, and algae. They have less differentiation in tissues and organs. In contrast, advanced organisms, such as mammals and birds, have complex body structures, specialized organs, and are more capable of surviving in varied and challenging environments. Advanced organisms show greater behavioral and physiological adaptations.

q. Fern is a non-flowering plant while mustard is a flowering plant; but both of them are placed in the same division. What is the reason for it?
Both fern and mustard belong to the division Tracheophyta (vascular plants). While ferns are non-flowering plants that reproduce via spores, and mustard is a flowering plant that reproduces via seeds, they are placed in the same division because they share common features like vascular tissue (xylem and phloem) that transport water and nutrients, and both are land plants. The primary distinction lies in their mode of reproduction, but they are still part of the larger group of vascular plants.

r. Write some similarities between gymnosperms and angiosperms.
Gymnosperms and angiosperms share the following similarities:

Both are seed plants: Both groups produce seeds as part of their reproductive cycle.
Vascular Tissue: Both gymnosperms and angiosperms have vascular tissue (xylem and phloem) for transporting water and nutrients.
Adaptation to Land: Both groups are adapted to land environments and do not require water for fertilization (unlike some non-vascular plants).

s. Manoj observed some flowering plants in his surroundings and he claimed that they are all monocot plants. Is his conclusion right or not? Explain with reason.
Manoj's conclusion is not entirely accurate. While all monocots are flowering plants, not all flowering plants are monocots. Monocots are characterized by having one cotyledon in their seeds, parallel-veined leaves, and flower parts in multiples of three. However, flowering plants can also be dicots, which have two cotyledons, reticulate-veined leaves, and flower parts in multiples of four or five. Hence, Manoj should not assume that all flowering plants in his surroundings are monocots.

t. Can all the plants be classified into Pteridophyte, Gymnosperms, and Angiosperms on the basis of characteristics of their leaves only? Explain with reason.

No, all plants cannot be classified into Pteridophytes, Gymnosperms, and Angiosperms based solely on the characteristics of their leaves. While the structure of leaves is an important characteristic, classification of plants requires considering multiple features, such as reproductive methods, presence of seeds, and vascular tissue, among others.

Reasons:

Pteridophytes (e.g., ferns) have fronds (large, divided leaves), but they reproduce via spores rather than seeds. The presence of spores is a key factor distinguishing them from gymnosperms and angiosperms, which produce seeds.
Gymnosperms (e.g., pine trees) typically have needle-like or scale-like leaves, which help conserve water. However, gymnosperms reproduce by naked seeds in cones, unlike pteridophytes that use spores.
Angiosperms (e.g., roses, mangoes) generally have broad, flat leaves and reproduce by seeds enclosed in fruits. Their leaves may vary widely, but the presence of flowers and fruits is a distinguishing feature that separates them from pteridophytes and gymnosperms

u. Whale, fish, and crocodile live in water. On the basis of characteristics, write which is the most developed one and which is the least developed. Explain with reason.

Most Developed: Whale
Whales are mammals, warm-blooded, give live birth, and have advanced brains and complex behaviors. They also have efficient lungs and adaptations for aquatic life.
Least Developed: Fish
Fish are cold-blooded, lay eggs with external fertilization, and have gills for breathing, making them simpler compared to whales and crocodiles.
Moderately Developed: Crocodile
Crocodiles are cold-blooded, breathe through lungs, and have internal fertilization, making them more developed than fish but less than whales

6. Give reason

a.The sea horse is placed under the class of Pisces.

Sea horse is placed in Pisces because it has fins, gills, and lives in water like other fishes.

b. Mustard is a dicotyledonous plant.

Mustard is a dicot because its seeds have two cotyledons and leaves show net-like venation.

c. The bryophytes are called amphibian plants.

Bryophytes are called amphibians of the plant kingdom as they need water for reproduction.

d. Maize is a monocotyledon.

Maize is a monocot because it has one cotyledon, parallel leaf venation, and fibrous roots.

e. Gymnosperms have no fruits.

Gymnosperms have no fruits because their seeds are naked and not enclosed in fruits.

f.Birds are called glorified reptiles.

Birds are called glorified reptiles as they evolved from reptiles and share features like scaly legs.

g. Sponges belong to the phylum Porifera.

Sponges belong to Porifera because they have pores, a canal system, and no true tissues.

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HOMEWORK FOR CLASS 10

Chapter 2

i. Name the classes of vertebrates and give one example for each.

j. Enlist four characteristics of Mammalia.

k. What are vertebrates? Mention their characteristics.

Reasons: