Frank Brothers Solutions for ICSE Class 9 Biology Chapter 13 Diversity Of Life And Classification

PAGE NO: 117

Question 1:
Answer:
Diversity refers to the variety of living organisms found within a given ecosystem, biome, or on an entire planet.
Diversity shows how different every living creature is from one another. It highlights the vast number of species sharing our Earth.
Teacher's Tip: Think of "Diversity" as "Different" to remember it means variety.
Exam Tip: Mention the three levels - ecosystem, biome, and planet - to get full marks.

Question 2:
Answer:
The method of arranging organisms into series of groups on the basis of similarities and differences is called classification.
Classification is important in the following ways:
1. It makes the study of a wide variety of organisms easy.
2. It gives us an overall picture of all the life-forms.
3. It helps us to understand the interrelationships among different groups of organisms.
4. It forms a base for the development of other biological sciences.
Classification helps scientists organize millions of species into neat folders. It makes finding information about a specific animal much faster.
Teacher's Tip: Think of your school library; books are classified so you can find them easily!
Exam Tip: List at least three points of importance when asked about classification.

Question 3:
Answer:

• According to binomial system, all organisms are given two proper names.
• The first is the generic name beginning with a capital letter whereas the second is the species name starting with a small letter.
• Both these names are underlined when written or italicised when printed.
• Naming organisms using this system avoids confusion among people all over the world.

Example -
Common name Scientific name
Pea -> Pisum sativum
Wheat -> Triticum aestivum
Earthworm -> Pheretima posthuma
Lion -> Panthera leo
Every living thing has a unique "first name" and "last name" in science. This system is used by scientists globally so they all know exactly which organism they are talking about.
Teacher's Tip: "Bi" means two and "nomial" means name, so "Binomial" just means two-names.
Exam Tip: Always remember to capitalize the first letter of the first word and keep the second word in lowercase.

Question 4:
Answer:
Taxonomy is the study of the theory, practice and rules of classification of living and extinct organisms.
Taxonomy is like the rulebook for naming and grouping life. It applies to creatures that are alive today and those that died out millions of years ago.
Teacher's Tip: Think of a Taxonomist as a "Biological Accountant" who sorts and names everything.
Exam Tip: Include "living and extinct" in your definition to show complete understanding.

Question 5:
Answer:
The five kingdom system of classification was proposed by R. H. Whittaker in 1969. This classification is based on the following four facts:

• Complexity of cell structure
• Methods of nutrition (autotrophic or heterotrophic)
• Complexity of body organization.
• Phylogenetic relationships.

The five kingdoms in this system are:
1. Monera - It includes all the prokaryotes like bacteria and cyanobacteria. They are important decomposers.
2. Protista - It includes the aquatic, eukaryotic, acellular organisms like protozoans.
3. Fungi - This kingdom includes moulds, mushrooms and yeasts.
4. Plantae - It includes all the coloured, multicellular, eukaryotes with cell walls.
5. Animalia - These are multicellular eukaryotes lacking cell wall and showing heterotrophic nutrition.
This system is the most widely used way to sort life into five huge groups. It looks at how cells work and how the organism gets its energy.
Teacher's Tip: Use the first letters M-P-F-P-A (Monera, Protista, Fungi, Plantae, Animalia) to memorize the order.
Exam Tip: Always mention R.H. Whittaker as the person who proposed this system.

Question 6:
Answer:
Important characters of five kingdom are:
Characters of kingdom Monera are:
1. It contains acellular organisms, ranging in size between 0.15 to 2.0 .
2. They are prokaryotes, lacking a well-defined nucleus .
3. They usually lack chlorophyll and hence are parasites or saprophytes.
4. Reproduction occurs by binary fission or budding in bacteria.
Example - Actinomycetes, bacteria, cyanobacteria.
Characters of kingdom Protista are:
1. They are aquatic, unicellular organisms.
2. They have eukaryotic cells with well-defined nucleus and organelles.
3. They show autotrophic or heterotrophic mode of nutrition.
4. Some protists are parasites and few are decomposers too.
Example - Euglena, Ameoba, Paramoecium.
Characters of kingdom Fungi:
1. They may be unicellular or multicellular.
2. They have heterotrophic nutrition and mostly they are saprophytes.
3. Their body is made up of mycelium, a filament of which is called hypha.
4. Their cell wall is made up of chitin.
Example - Aspergillus, Agaricus, Penicillium.
Characters of kingdom Plantae:
1. They are multicellular, eukaryotic organisms.
2. The cell membrane is surrounded by a thick cell wall of cellulose.
3. Except a few aquatic life forms, plants are non-motile.
4. They have different modes of nutrition: autotrophic, parasitic even insectivorous.
Example - Mango, Cycas, Fern, Moss.
Characters of kingdom Animalia:
1. They are multicellular, eukaryotic organisms without cell wall.
2. They show heterotrophic mode of nutrition.
3. They can retract or expand with the help of muscles.
4. They are consumers in-between producers and decomposers.
Example - Fish, Frog, Earthworm, Man.
Each kingdom has special rules about how its members live and what their bodies are made of. For example, animals have muscles to move, while plants are mostly stuck in one place.
Teacher's Tip: Fungi have cell walls made of "Chitin" (sounds like kite-in), while plants use "Cellulose".
Exam Tip: Providing at least one specific example for each kingdom makes your answer much stronger.

Question 7:
Answer:
The kingdom Plantae has been divided into following groups:
Thallophyta

• They are consists of red, green and brown algae.
• Algae are of universal occurrence.
• Their body ranges from unicellular to multicellular colonies, filaments or sheets of cells.
• Vascular tissues are absent.
• Nutrition is generally autotrophic (through photosynthesis).
• Reproduction is vegetative or sexual.

Bryophyta

• It consists of liverworts and mosses.
• They are terrestrial, found in damp, shady places.
• Their life cycle has a long gametophytic phase and a short sporophytic phase.
• Liverworts have prostrate thalloid gametophytic body, but mosses have erect body.
• True roots are absent, but rhizoids presents.
• Vascular tissues are absent.
• Nutrition is generally autotrophic (through photosynthesis).
• Reproduction is vegetative or sexual.

Pteridophyta

• They include ferns, horse-tails and club mosses.
• They occur mainly in cool, shady and moist places.
• They are mostly terrestrial.
• They are perennial herbs with stem in the form of rhizome.
• Fibrous roots present.
• Their life cycle has a gametophytic phase and a short sporophytic phase.
• Vascular tissues are present.
• Nutrition is generally autotrophic (through photosynthesis).
• Reproduction is vegetative or sexual.

Spermatophyta

• They are the most successful terrestrial plants having seeds.
• They produce seeds (fertilized ovules).
• They are divided into two groups -

1. Gymnosperms - They bear naked seeds and lack flowers. Examples: Pine, Cycas
2. Angiosperms - They produce seeds enclosed in ovary and flowers are present. Examples: Rose, Grass
Plants are grouped based on whether they have seeds, roots, or transport tubes called vascular tissue. Spermatophytes are the most advanced because they can grow far from water using seeds.
Teacher's Tip: Thallophyta are the simplest (like algae), while Angiosperms are the most complex (flowering plants).
Exam Tip: Distinguish between Gymnosperms (naked seeds) and Angiosperms (seeds inside fruit/flowers).

Question 8:
Answer:
Animals. Cellular level of organisation -> Porifera. Tissue level of organisation -> No body cavity between epidermis and gastrodermis (Coelenterata, Platyhelminthes). Pseudocoelom (Nematoda). Coelomate (Mesodermal cells from a single cell during growth of the embryo -> Annelida, Mollusca, Arthropoda. Coelom formed from pouches pinched off from the endoderm -> No notochord -> Echinodermata. Notochord present -> Chordata). Chordata -> Notochord in at least larval forms, but very rudimentary (Protochordata). Notochord replaced by vertebral column in adults (Vertebrata). Vertebrata -> Pisces, Amphibia, Reptilia, Aves, Mammalia. Flow-chart showing various sub-divisions of kingdom Animalia.
This chart shows how animals are sorted from the simplest sponges to the most complex mammals. It uses features like body cavities and backbones to draw the lines.
Teacher's Tip: Use this chart as a map to see how different animal groups are related.
Exam Tip: Be able to name the five classes of vertebrates (Pisces to Mammalia) in the correct order.

Question 9:
Answer:
The non- chordates are divided into nine phyla:
(i) Protozoa -> Euglena , Amoeba
(ii) Porifera -> Sycon, Euplectella
(iii) Coelenterata -> Hydra, Physalia
(iv) Platyhelminthes -> Fasciola, Dugesia
(v) Nemathelminthes -> Ascaris, Wuchereria
(vi) Annelida -> Nereis, Hirudinaria
(vii) Mollusca -> Unio, Pila
(viii) Arthropoda -> Palemon, Periplaneta
(ix) Echinodermata -> Antedon, Echinus
Non-chordates are animals that do not have a backbone or a spinal cord. This huge group includes everything from tiny pond creatures to crabs and snails.
Teacher's Tip: "Phyla" is just the plural word for Phylum, a big group in classification.
Exam Tip: Memorize at least one example for each phylum to illustrate your answers.

Question 10:
Answer:
The various classes of Chordata are:
1. Pisces - Labeo (Rohu), Scoliodon (Dog fish)
2. Amphibia - Rana (Frog), Hyla (Tree frog )
3. Reptilia - Kanchuga (Tortoise), Naja naja ( Cobra)
4. Aves - Columba (Pigeon), Pavo (Peacock)
5. Mammalia - Elephas ( Elephant), Funambulas (Squirrel)
These are the animals we are most familiar with, having some form of a backbone. They are categorized by how they breathe and where they live.
Teacher's Tip: Think of "P-A-R-A-M" (Pisces, Amphibia, Reptiles, Aves, Mammals) to remember the classes.
Exam Tip: "Aves" is the scientific name for the bird group.

Question 11:
Answer:
Important chordate characters are:
(i) Presence of dorsal, hollow, tubular, nerve cord
(ii) Presence of long notochord
(iii) Presence of series of gill slits.
CHORDATES:
Notochord is found in all stages of the life-cycle.
Heart is situated on ventral side of the alimentary canal.
Nervous system is situated on the dorsal side.
RBCs are present in blood.
NON-CHORDATES:
Notochord is not found in any stages of the life-cycle.
Heart is poorly formed and if present it is situated on the dorsal side.
Nervous system is situated on the ventral side.
RBCs are absent in blood.
The main difference is the "notochord," which eventually becomes our spine. Chordates also have more complex hearts and nervous systems.
Teacher's Tip: In chordates, the heart is "in the front" (ventral) and the nerves are "in the back" (dorsal).
Exam Tip: Draw a table with these 4 points of difference to score full marks in comparisons.

Question 12:
Answer:
Characters of mammals are:
1. The females of this class are provided with mammary glands which produces milk to feed the young one.
2. Body usually covered with hair, spines, scales, nail, hoof or horn.
3. External ear or pinna is well-developed.
4. They are warm-blooded.
Mammals are unique because they care for their babies with milk. Most mammals also have hair or fur and ears that stick out.
Teacher's Tip: Humans are mammals too! Think of your own body to remember these features.
Exam Tip: Mention "mammary glands" as the defining feature of this class.

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Question 13:
Answer:
(a) Starfish belongs to phylum Echinodermata. Two characters of starfish are:
1. Spines found on the body which is covered by calcareous plates.
2. Body is star shaped with five radiating areas called ambulacra with inter-ambulacra in between.
(b) Whale belongs to phylum Chordata. Two characters of whale are:
1. They are warm blooded marine animals.
2. Heart is completely four-chambered.
(c) Jelly fish belongs to phylum Coelenterata. Two characters of jelly fish are:
1. Body diploblastic having outer epidermis and inner gastrodermis with gelatinous mesoglea.
2. Tentacles are present around the mouth.
(d) Cockroach belongs to phylum Arthropoda. Two characters of cockroach are:
1. They have jointed legs.
2. Their exoskeleton is made up of chitinous cuticle which is shed from time to time.
Each of these animals belongs to a different phylum because of how their bodies are built. For example, insects like cockroaches have hard "shells" called exoskeletons.
Teacher's Tip: Cockroaches "shed" their skin, which is called moulting.
Exam Tip: Be sure to identify the phylum correctly before listing the characters.

Question 14:
Answer:
GYMNOSPERMS:
Seeds are naked. Flowers are absent.
Reproductive organs are in the form of cones.
E.g. - Pine, Cycas, Taxus
ANGIOSPERMS:
Seeds are enclosed in ovary. Flowers are present.
Reproductive organs are flowers.
E.g. Rose, Sandal wood, sunflower
Gymnosperms have seeds that sit out in the open (like in pine cones). Angiosperms protect their seeds inside flowers and fruits.
Teacher's Tip: "Gymno" means naked and "Sperma" means seed.
Exam Tip: Note that Angiosperms represent the vast majority of plants we see in gardens.

Question 15:
Answer:
Bryophyta - Liverwort and Moss.
Pteridophyta - Fern and Horsetail.
These are examples of "lower" plants that don't produce seeds. They usually grow in damp, shady places.
Teacher's Tip: Mosses are the tiny green carpets you see on wet rocks.
Exam Tip: Keep the pairings correct (Liverworts with Bryophyta, Ferns with Pteridophyta).

Question 16:
Answer:
Antedon (Sea lily) and Asterias (Star fish ).
These are two different creatures found in the ocean that belong to the same group. Even though they look different, they share a similar body plan.
Teacher's Tip: Even though it's called a "lily," the Sea lily is actually an animal!
Exam Tip: Learn the scientific names like "Asterias" for the common name "Starfish."

Question 17:
Answer:
Whale
A whale is an aquatic mammal that breathes air and gives birth to live young. This makes it very different from most other sea creatures like fish.
Teacher's Tip: Whales are mammals, not fish!
Exam Tip: Mention "Whale" when asked for an example of a marine mammal.

Question 18:
Answer:
Cockroach, crab
Both of these animals have hard outer shells and jointed legs. They belong to the phylum Arthropoda, which is the largest group in the animal kingdom.
Teacher's Tip: If it has jointed legs and a crunchy shell, it's an Arthropod.
Exam Tip: Cockroaches and crabs are great examples for the Phylum Arthropoda.

Question 19:
Answer:
Frog
Frogs are amphibians that spend part of their life in water and part on land. They have smooth, moist skin and lay their eggs in water.
Teacher's Tip: Amphibians lead a "double life" - water and land.
Exam Tip: Frogs belong to the class Amphibia because they can live in both environments.

Question 20:
Answer:
Echidna
The Echidna is a rare type of mammal that actually lays eggs instead of giving birth. It is found in Australia and has spines all over its body for protection.
Teacher's Tip: Echidnas are special because they are "egg-laying mammals."
Exam Tip: Use Echidna as an example of a primitive or unusual mammal.

Question 21:
Answer:
Earthworm - Pheretima posthuma and
Roundworm - Ascaris
These are the scientific names for two very different kinds of worms. The earthworm is helpful to soil, while the roundworm is often a parasite.
Teacher's Tip: Pheretima is the "good" worm for your garden!
Exam Tip: Write out scientific names like "Ascaris" clearly to show taxonomic accuracy.

Question 22:
Answer:
Cobra -> Reptilia
Peacock -> Aves
Earthworm -> Annelida
Euglena -> Protozoa
Frog -> Amphibia
Spongilla -> Porifera
This list pairs famous animals with their correct scientific classes or phyla. It's a great summary of the animal kingdom and how life is organized.
Teacher's Tip: Use arrows to show the relationship between the animal and its group.
Exam Tip: Double-check each pair; matching the wrong class to an animal is a common mistake.

Question 23:
Answer:
(a) Arthropoda
(b) Porifera
(c) Mollusca
These are the names of phyla that contain specific types of animals like insects, sponges, and snails. They represent major branches of the animal kingdom tree.
Teacher's Tip: Arthropoda is the largest phylum in the world.
Exam Tip: Spelling counts for these long scientific names!

Question 24:
Answer:
(a) Protozoa
(b) Mollusca
(c) Annelida
More phylum identifications. These groups cover everything from microscopic single-celled life to segmented worms that help our environment.
Teacher's Tip: Annelids are the "ringed" worms like your garden earthworms.
Exam Tip: Read the animal characteristics carefully to pick the right phylum.

Question 25:
Answer:
(a) Asterias (Star fish ), Echinus (Sea-urchin)
(b) Scoliodon (Dog fish), Labeo (Rohu)
(c) Fasciola ( Liver fluke), Taenia solium (Tapeworm)
(d) Ascaris ( Roundworm), Wuchereria (Filarial worm )
(e) Pheretima (Earthworm), Hirudinaria ( Leech )
(f) Palemon (Prawn), Periplaneta (Cockroach)
This gives you the scientific names of common animals found in nature. It's important to know the "official" name used in biology to communicate with other scientists.
Teacher's Tip: "Labeo rohu" is a very common fish found in many markets.
Exam Tip: Put the scientific name first and the common name in brackets for clarity.

Question 26:
Answer:
(a) Annelida
(b) Coelenterata
(c) Arthropoda
(d) Echinodermata
These answers identify the phylum based on specific physical traits mentioned in your textbook. Understanding these traits helps you classify any new animal you might find.
Teacher's Tip: Coelenterates like jellyfish use special stinging cells to hunt.
Exam Tip: Link "jointed legs" immediately to "Arthropoda" in your mind.

Question 27:
Answer:
(a) Flame cells
(b) Nemathelminthes
(c) Annelida
(d) Porifera
(e) Chordata
These are specific biological structures or groups. For instance, flame cells are used by some primitive worms to get rid of liquid waste from their bodies.
Teacher's Tip: Think of "Flame cells" as the "tiny kidneys" of flatworms.
Exam Tip: Use these specific terms to answer one-mark questions accurately and quickly.

Question 28:
Answer:
1. (a) three pairs of legs are present.
2. (a) coelentrata
3. (c) octopus
4. (c) paramoecium
5. (c) hippocampus
6. (a) Scorpion
7. (b) for five kingdom classification
8. (a) prokaryotic and multicellular eukaryotic cell
9. (d) plant
10. (d) C. Linnaeus
11. (c) Carolus Linnaeus
These are the correct choices for the multiple-choice section. They summarize important facts like who created the naming system and how many legs insects have.
Teacher's Tip: C. Linnaeus and Carolus Linnaeus are the same person!
Exam Tip: Always check if the question asks for the "incorrect" or "correct" statement before choosing an option.