Patterns in Life: Diversity and Classification Class 9 Notes and Questions

What Patterns in Life: Diversity and Classification is about

Weightage: This chapter is part of Unit I, World of Living, which carries 27 of the 80 theory marks in the school annual exam, shared with Cell: The Building Block of Life, Tissues in Action and Reproduction: How Life Continues.Source: CBSE Science (086) syllabus, Class IX 2026-27, course structure, Unit I World of Living

Key concepts

Biodiversity, endemic species and hotspots

NCERT section 12.1 India as a Biodiversity Hotspot

Biodiversity is the variety of living things on the Earth. Every organism has a role: ocean algae release much of our oxygen; fungi and bacteria decompose waste and make soil fertile; birds, bees and bats pollinate; plants make food for nearly all life. Humans depend on biodiversity for food, shelter, medicines and livelihoods, and farmers have long kept many crop varieties (drought-tolerant, pest-resistant) to reduce the risk of crop failure.

Endemic species are found naturally in only one region. Examples found only in India: Nilgiri tahr, lion-tailed macaque, the pitcher plant *Nepenthes khasiana*, Neelakurinji, the Sangai deer of Manipur and the purple frog of the Western Ghats.

Biodiversity hotspots are regions with many endemic species that have lost much of their habitat. India has parts of four: Western Ghats, Indo-Burma (including North-East India), Himalaya, and Sundaland (including the Nicobar Islands).

How diversity evolved: small differences among individuals affect their survival and reproduction; over many generations these differences accumulate and new forms arise.

Traditional practices such as sacred groves and the Sangam Tinai classification of landscapes helped protect local diversity.

Worked example

Pakke Tiger Reserve in Arunachal Pradesh has about 300 bird species, while all of India has about 1300. What percentage of India's bird species live there? What does this suggest about the area?

Try it first, then show the solutionSolution

1. $\frac{300}{1300}\times 100\approx 23\%$.
2. Nearly a quarter of India's bird species in one reserve shows very high biodiversity.
3. Such areas are especially important to protect.

Answer: About 23%; Pakke is extremely rich in bird diversity and a conservation priority.

Criteria and need for classification

NCERT section 12.4 The Need for Classification

The same organisms can be grouped in many ways (by habitat, time of activity, food). Scientists choose features that show real relationships, starting broad and getting more detailed:
1. External features: shape, size, body organisation.
2. Mode of nutrition: autotrophic (make own food) or heterotrophic (depend on others).
3. Internal structure: skeleton, organs, tissues.
4. Cell structure: unicellular or multicellular; prokaryotic or eukaryotic; cell wall present or not.
5. Ecological role: producer, consumer or decomposer.
6. Reproduction: asexual and/or sexual.
7. Genetic similarity: compared using DNA.
Shared features suggest a common ancestor.

Why classify? (Like finding a book in a sorted library.)

• Makes study organised and systematic.
• Shows similarities and differences.
• Shows relationships and interactions.
• Helps identify and name new organisms.
• Helps conservation by identifying threatened species.
• Gives scientists worldwide a common system.

Case: Pakke's four hornbills (Rufous-necked, Oriental Pied, Great, Wreathed) look alike but differ in features such as casque, colour and size. They nest only in large old trees with cavities and eat particular fruits, so classifying them helps scientists see how species are spread through the forest and what would happen if old trees were cut.

Worked example

A student groups an owl, a bat and a moth together as 'night fliers'. Why is this not a good scientific grouping? Which criteria would a scientist use instead?

Try it first, then show the solutionSolution

1. Habitat or behaviour can be shared by unrelated organisms: a bird (owl), a mammal (bat) and an insect (moth).
2. A scientist would look at cell structure, body organisation, skeleton, body covering, reproduction and DNA.
3. These place the owl with birds, the bat with mammals and the moth with arthropods.

Answer: Behaviour alone groups unrelated animals; structure, reproduction and DNA show real relationships.

Classification systems over time and the five kingdoms

NCERT section 12.5 Biological Classification Systems Over Time

When	Who	System
4th century BCE	Aristotle	animals by habitat (land, water, air) and appearance
1758	Linnaeus	two kingdoms: Plantae, Animalia
1866	Haeckel	three: + Protista (unicellular)
1938	Copeland	four: + Monera (no true nucleus)
1969	R. H. Whittaker	five: + Fungi

The Rigveda and Brihat Samhita grouped animals by habitat, behaviour and ecological role.

Why changes were needed: *Amoeba* moves like an animal but is one cell; bacteria have no true nucleus; fungi do not move and do not photosynthesise but absorb food.

Five-kingdom criteria: cell type (prokaryotic or eukaryotic), cell wall (present or absent, and of what), level of organisation (unicellular or multicellular), mode of nutrition (autotrophic or heterotrophic).

Kingdom	Cell type	Cells	Cell wall	Nutrition	Examples
Monera	prokaryotic	unicellular	present	auto- or heterotrophic	bacteria, cyanobacteria
Protista	eukaryotic	unicellular	absent or cellulose	auto- or heterotrophic	*Amoeba*, *Paramecium*, *Euglena*, *Chlamydomonas*
Fungi	eukaryotic	mostly multicellular (yeast unicellular)	chitin	heterotrophic (absorb; mostly decomposers)	mushroom, yeast, *Aspergillus*, *Penicillium*
Plantae	eukaryotic	multicellular	cellulose	autotrophic (photosynthesis)	moss, fern, pine, rose
Animalia	eukaryotic	multicellular	none	heterotrophic	ant, frog, bird, human

Three domains (Carl Woese, 1977, based on DNA): Bacteria, Archaea, Eukarya.

Worked example

A pond sample shows a single-celled organism with a well-defined nucleus, a cup-shaped chloroplast and two flagella (Chlamydomonas). Which kingdom does it belong to? Why is it not placed in Plantae, even though it photosynthesises?

Try it first, then show the solutionSolution

1. A well-defined nucleus makes it eukaryotic, so not Monera.
2. It is unicellular, and unicellular eukaryotes are placed in Protista.
3. Plantae contains only multicellular organisms, so photosynthesis alone is not enough to make it a plant.

Answer: Protista; it is a unicellular eukaryote, while Plantae is multicellular.

Monera, Protista and Fungi in more detail

NCERT section 12.6 Five Kingdom Classification

Monera (Activity 12.4, slides of bacteria and cyanobacteria):

• Found everywhere: soil, water, air, hot springs, salty and other extreme places, and inside our bodies.
• Bacteria in the gut of cattle help make biogas from dung (Ram Bux Singh set up India's first scientific biogas plant in 1957).
• Some cause disease; many are useful: *Lactobacillus* (curd), *Rhizobium* (nitrogen fixing in root nodules); some break down oil, pesticides and sewage.
• Cyanobacteria are photosynthetic and were among the first to release oxygen (about 2.5 billion years ago); their fossils (stromatolites) are found in Rajasthan and Madhya Pradesh.

Protista (Activity 12.5, hay infusion): grass or straw left in pond water for a week, covered with muslin, swarms with protists. They live in water or moist places; some photosynthesise, some eat; they are key links in aquatic food chains. (Handle with gloves and mask; it smells.)

Fungi:

• Cell wall of chitin; no chlorophyll; body of fine threads (hyphae) forming a mycelium that absorbs food.
• Mostly saprophytes (decomposers of dead matter), returning minerals to soil; some are symbiotic, some parasitic.
• Reproduce by spores; grow best in warm, moist places.
• Useful: *Penicillium* and *Aspergillus* for antibiotics and enzymes; yeast for bread; mushrooms as food (cultivation takes only 30 to 45 days). Tribal communities use folk knowledge to tell edible from poisonous mushrooms.
• Lichens are partnerships of an alga (makes food) and a fungus (gives protection); they are bioindicators of clean air and some are used as spice (*patthar ke phool*) and dyes.

Worked example

A white, fuzzy growth on stale bread is made of fine threads with cell walls but no chlorophyll. Which kingdom does it belong to, what are the threads called, and how does it get its food?

Try it first, then show the solutionSolution

1. No chlorophyll, a cell wall and a body of threads point to Fungi.
2. The threads are hyphae; together they form a mycelium.
3. It is a saprophyte: it absorbs food from the dead organic matter of the bread.

Answer: Fungi; hyphae (forming a mycelium); it absorbs food from the bread (saprophytic).

Kingdom Plantae: five groups

NCERT section 12.6 Five Kingdom Classification

Plants are multicellular, autotrophic, with cellulose cell walls; they form the base of food chains and release oxygen.

Group	Meaning	Body	Transport tissue	Seeds	Water for reproduction	Examples
Thallophyta (algae)	thallus = undifferentiated body	simple thallus, no root, stem or leaf	no	no	yes (live in water)	*Spirogyra*, *Ulva*, *Chara*
Bryophyta	bryon = moss	small; rhizoids, simple stem- and leaf-like parts	no	no	yes: 'amphibians of the plant kingdom'	moss, *Marchantia* (liverwort)
Pteridophyta	pteron = feather	true roots, stems and leaves	yes (xylem, phloem)	no	yes	ferns (*Marsilea*, *Pteris*)
Gymnosperms	gymnos = naked, sperma = seed	trees with needle- or scale-like leaves	yes	yes, naked (on cones, not in fruits)	no	pine, cycas, deodar
Angiosperms	angeion = vessel	most complex	yes	yes, inside fruits; have flowers	no	mango, rose, grasses, gulmohar

The sequence shows plants solving life on land step by step: support and water transport (vascular tissue), reproduction without water (seeds), and better pollination and dispersal (flowers and fruits). Angiosperms are the most diverse group. They are often divided by leaves into monocots (parallel veins, e.g. grasses) and dicots (net veins, e.g. mango) (Activity 12.8).

*Hortus Malabaricus* (17th century), compiled by van Rheede with the healer Itty Achudan, recorded hundreds of Kerala plants and their medicinal uses.

Worked example

Ferns and pine trees both have true roots, stems, leaves and vascular tissue. Why are they placed in different groups?

Try it first, then show the solutionSolution

1. Ferns (pteridophytes) do not make seeds and need water for reproduction.
2. Pines (gymnosperms) make seeds, carried naked on cones, and do not need water for fertilisation.
3. So the presence of seeds separates the two groups.

Answer: Pines make naked seeds on cones; ferns make no seeds and need water to reproduce.

Kingdom Animalia: invertebrate phyla

NCERT section 12.6 Five Kingdom Classification

Animals are multicellular heterotrophs with no cell wall; most move and respond quickly. The first big division is the notochord (a flexible supporting rod): non-chordates (invertebrates) lack it; chordates have it.

Phylum	Key features	Level of organisation	Examples
Porifera (pore-bearers)	many pores; water flows through bringing food and oxygen; fixed	cellular (no true tissues)	sponges
Cnidaria	tentacles to catch prey; one opening for food and waste	tissue	*Hydra*, jellyfish, corals
Platyhelminthes (flatworms)	flat; bilaterally symmetrical (head and tail ends); one opening; many parasitic with hooks and suckers	organ	tapeworm, liver fluke, *Planaria*
Nematoda (roundworms)	long, cylindrical; two openings (mouth and anus); separate sexes	organ system	*Ascaris*, hookworm
Annelida (segmented worms)	body in segments; muscles and a nerve cord; body cavity	organ system	earthworm, leech
Arthropoda (jointed legs)	segmented body; jointed appendages; hard exoskeleton that protects, cuts water loss and supports muscles	organ system	insects (butterfly), crab, spider
Mollusca	soft body with a head, muscular foot and hump; often a shell	organ system	snail, octopus, squid
Echinodermata (spiny skin)	spiny skin; marine; internal skeleton of calcium carbonate	organ system	starfish, sea urchin

The trend is towards more complex bodies, with each new feature (tissues, two openings, segments, jointed legs) bringing advantages and new challenges. A kilogram of sponge can filter about 24 000 L of sea water a day.

Parasitic worms enter through contaminated food and water: wash hands, cook food well and drink boiled or filtered water.

Worked example

Under a damp stone a student finds an animal with a soft body, a muscular foot and a coiled shell. On a beach she finds one with spiny skin and five arms. Name the phylum of each and give one feature that separates the first from an earthworm.

Try it first, then show the solutionSolution

1. Soft body, muscular foot and shell: Mollusca (a snail).
2. Spiny skin, marine, with an internal skeleton of calcium carbonate: Echinodermata (a starfish).
3. An earthworm (Annelida) has a ring-segmented body and no shell or muscular foot.

Answer: Mollusca (snail) and Echinodermata (starfish); the snail has a shell and foot, not a segmented body.

Chordates: protochordates and vertebrates

NCERT section 12.7 Adaptations as Outcomes of Structural Change

Protochordates (e.g. *Amphioxus*, *Balanoglossus*) have a notochord at least at some stage of life but no backbone. They show how animals with a notochord may have arisen.

Vertebrates have a vertebral column (backbone) that supports the body and protects the spinal cord, with a skull protecting the brain. This allows larger size, efficient movement and complex organ systems.

Class	Habitat	Body covering	Breathing	Reproduction	Examples
Fish (Pisces)	water	scales	gills	eggs laid in water	rohu, shark, seahorse
Amphibians	water and land	moist skin, no scales	gills as larvae; lungs and skin as adults	eggs in water; larva (tadpole)	frog, toad, salamander
Reptiles	mostly land	dry scales	lungs	shelled eggs on land	lizard, snake, turtle, crocodile
Birds (Aves)	air and land	feathers	lungs	shelled eggs; warm-blooded	sparrow, peacock, hornbill
Mammals	land, water, air	hair or fur	lungs	most give birth; mammary glands feed young; warm-blooded	human, cat, whale, bat

Adaptations as structural change: fins and gills (fish), feathers and hollow bones (birds), fat stores in camels, thick fur in polar bears, mammary glands in mammals for better survival of young.

Worked example

Animal W has a backbone, dry scaly skin, breathes with lungs and lays shelled eggs on land. Animal V has a backbone and hair and feeds its young on milk. Name the class of each. Why can 'lives on land' alone not separate them?

Try it first, then show the solutionSolution

1. W: dry scales, lungs and shelled eggs on land: Reptilia (e.g. a lizard).
2. V: hair and mammary glands: Mammalia (e.g. a cat).
3. Both live on land and both are heterotrophic, so habitat and nutrition cannot separate them; body covering and reproduction can.

Answer: W is a reptile, V a mammal; habitat is shared, so body covering and reproduction are needed.

Hierarchy and binomial nomenclature

NCERT section 12.8 Scientific Naming — The Binomial System

Classification is a hierarchy from broad to specific:

Kingdom → Phylum → Class → Order → Family → Genus → Species

Like a postal address, each lower level is part of the one above. Lower levels have fewer members but share more features.

Level	Tiger	Pea
Kingdom	Animalia	Plantae
Phylum	Chordata (sub-phylum Vertebrata)	Magnoliophyta
Class	Mammalia	Magnoliopsida
Order	Carnivora	Fabales
Family	Felidae	Fabaceae
Genus	*Panthera*	*Pisum*
Species	*P. tigris*	*P. sativum*

Binomial nomenclature (Carolus Linnaeus, 18th century): every organism has a two-part scientific name in Latin or Latinised form: genus + species. It avoids confusion between local names (*bagh*, *puli*, tiger, *tigre*).

Rules:
1. Two parts: genus first, then species.
2. Genus starts with a capital letter; species is all lower case.
3. Italics when printed; underlined separately when handwritten.

Examples: *Panthera tigris* (tiger), *Panthera leo* (lion; same genus of roaring cats), *Mangifera indica* (mango), *Homo sapiens* (human), *Pisum sativum* (pea), *Nasikabatrachus sahyadrensis* (purple frog, named after the Sahyadri hills).

A species is a group of similar individuals that can interbreed and produce fertile offspring.

Worked example

Correct the errors: (i) 'panthera Leo' (ii) 'Mangifera Indica'. (iii) For the tiger, which has more members, order Carnivora or family Felidae, and which shares more features?

Try it first, then show the solutionSolution

1. (i) Genus capital, species lower case, italics: *Panthera leo*.
2. (ii) *Mangifera indica*.
3. (iii) Order Carnivora includes cats, dogs, bears and more, so it has more members than family Felidae (cats only).
4. Members of the family share more features than members of the order.

Answer: Panthera leo, Mangifera indica (italics); the order has more members, the family shares more features.

Viruses, fossils and biodiversity under threat

NCERT section 12.10 Biodiversity Under Threat

Viruses: acellular entities

• Made of genetic material (DNA or RNA) inside a protein coat; no cell, no cytoplasm, no cell membrane, no organelles.
• Outside a host cell they are inactive (can even be crystallised); inside a living cell they use the cell's machinery to make copies.
• So they do not fit any of the five kingdoms, which are all based on cells. They show that classification systems have limits and keep changing with new knowledge.
• Examples of viral diseases: common cold, influenza, measles, polio, COVID-19, dengue.

Fossils are preserved remains or traces of organisms in rocks, sand and mud. Older (deeper) layers generally hold simpler forms, newer layers more complex ones, giving evidence of how life changed. Birbal Sahni studied fossil plants and founded the Birbal Sahni Institute of Palaeosciences, Lucknow.

Threats to biodiversity: deforestation, pollution, over-use of resources and climate change. When one species disappears, those depending on it may also decline. Example: the Sangai deer lives on phumdis, floating grasslands of Loktak Lake, Manipur; it was thought extinct in 1951, rediscovered in 1953, and is endangered as its habitat degrades.

Diverse ecosystems also protect people: villages with more mangroves suffered less damage in the 1999 Odisha super cyclone, and diverse forests can reduce disease spread and absorb pollutants.

Worked example

A student says, 'Viruses are just the smallest bacteria.' Correct this with two differences, and say why viruses are not in Monera.

Try it first, then show the solutionSolution

1. Bacteria are cells with a membrane, cytoplasm and ribosomes; viruses have no cell, only genetic material in a protein coat.
2. Bacteria grow and divide on their own; viruses are inactive outside a host and multiply only inside a living cell.
3. Monera is defined by prokaryotic cells, so acellular viruses cannot be placed there.

Answer: Bacteria are cells that multiply on their own; viruses are acellular and multiply only in host cells, so they are outside Monera.

Science in real life: Patterns in Life: Diversity and Classification

Each concept, met in an everyday situation. Read the situation, try the problem, then check the solution. The one-line hook is what to remember.

Topics in this chapter

• Criteria for Classification and the Five Kingdoms
• Plant and Animal Groups, Hierarchy and Binomial Names

Patterns in Life: Diversity and Classification: formulas and key facts

Hierarchy

$Kingdom\to Phylum\to Class\to Order\to Family\to Genus\to Species(lower=fewermembers,morefeaturesshared).$

Five kingdoms (Whittaker, 1969)

$Monera,Protista,Fungi,Plantae,Animalia.$

Five-kingdom criteria

Cell type, cell wall, level of organisation, mode of nutrition.

Cell walls

Plants: cellulose; fungi: chitin; animals: none; Monera: present; Protista: none or cellulose.

Plant groups

1. 1.Thallophyta
2. 2.Bryophyta
3. 3.Pteridophyta (vascular)
4. 4.Gymnosperms (naked seeds)
5. 5.Angiosperms (seeds in fruits, flowers).

Invertebrate phyla

$Porifera,Cnidaria,Platyhelminthes,Nematoda,Annelida,Arthropoda,Mollusca,Echinodermata.$

Vertebrate classes

$Fish,amphibians,reptiles,birds,mammals.$

Binomial name

*Genus species*: genus capital, species lower case, italics (underline by hand).

Timeline

$Aristotle(4thc.BCE)\to Linnaeus2kingdoms(1758)\to Haeckel3(1866)\to Copeland4(1938)\to Whittaker5(1969)\to Woese3domains(1977).$

Viruses

Acellular: genetic material + protein coat; active only inside a host cell; outside the five kingdoms.

Patterns in Life: Diversity and Classification: diagrams to practise

Practise each one on paper: draw it from the checklist, then tick off every label.

How the school exam asks Patterns in Life: Diversity and Classification

The question patterns to expect, and the method that works for each.

Tricks to remember Patterns in Life: Diversity and Classification

Short memory aids. Say each one aloud once, then use it on a question the same day.

• King Philip Came Over For Good Soup

  Kingdom, Phylum, Class, Order, Family, Genus, Species.

  Use it when: Order of the hierarchy.

• My Pet Fish Plays Alone

  Monera, Protista, Fungi, Plantae, Animalia.

  Use it when: Five kingdoms in order of complexity.

• Thank Brave People Giving Aid

  Thallophyta, Bryophyta, Pteridophyta, Gymnosperms, Angiosperms.

  Use it when: Plant groups from simplest.

• Please Come Play New Arcade Machines Every day

  Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata.

  Use it when: Invertebrate phyla in order.

• Chitin for Champignons, Cellulose for Crops

  Fungi (mushrooms) have chitin walls; plants have cellulose.

  Use it when: Cell-wall questions.

Patterns in Life: Diversity and Classification: exam-level solved questions

Ordered from exam level to HOTS. Cover the solution, write your own, then compare step by step.

Case-study practice (Section E style)

Read the situation, then answer every part. In a school exam set on the board pattern this is a 4-mark question split into 1 + 1 + 2 marks.

Where the marks are

How a typical answer is split into step marks. Show every step: a right final answer alone rarely earns full marks.

Where students lose marks in Patterns in Life: Diversity and Classification

The slips examiners see most often, and what to write instead.

• ✗Mistake: Writing scientific names wrongly

  Capitals and italics are ignored.

  Wrong working

  Homo Sapiens; mangifera indica (not underlined in handwriting).

  Right working

  *Homo sapiens*; *Mangifera indica*, each word underlined separately when handwritten.

  ✓Do this: Genus capital, species small, italic or underlined.

  Usually costs: 1 mark.

• ✗Mistake: Putting fungi in Plantae

  Mushrooms grow in soil and do not move.

  Wrong working

  Mushrooms are plants without chlorophyll.

  Right working

  Fungi have chitin walls and absorb food from dead matter; they form a separate kingdom.

  ✓Do this: No chlorophyll + chitin = Fungi.

  Usually costs: 1 mark.

• ✗Mistake: Saying gymnosperms have fruits

  Pine cones look like fruits.

  Wrong working

  Pine seeds are enclosed in fruits called cones.

  Right working

  Gymnosperm seeds are naked, lying on cone scales; only angiosperms have fruits.

  ✓Do this: Gymno = naked.

  Usually costs: 1 mark.

• ✗Mistake: Mixing up exoskeleton and endoskeleton

  Starfish look hard outside like crabs.

  Wrong working

  Starfish have an exoskeleton like arthropods.

  Right working

  Echinoderms have an internal skeleton of calcium carbonate; arthropods have a hard exoskeleton.

  ✓Do this: Echino- = inside support with spiny skin.

  Usually costs: 1 mark.

• ✗Mistake: Calling viruses bacteria or placing them in Monera

  Both cause disease and are tiny.

  Wrong working

  Viruses are the smallest Monera.

  Right working

  Viruses are acellular: genetic material in a protein coat, active only inside host cells; they are outside the five kingdoms.

  ✓Do this: No cell, no kingdom.

  Usually costs: 1 to 2 marks.

NCERT exercise guide: Patterns in Life: Diversity and Classification

What each exercise in the NCERT chapter tests, how to approach it, and a question of the same kind solved step by step. Questions here are written in our own words.

Practice questions on Patterns in Life: Diversity and Classification

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

1. Q1 · 1 mark · MCQExam level

   Bacteria belong to the kingdom
   (a) Protista
   (b) Monera
   (c) Fungi
   (d) Plantae

   Hint

   No true nucleus.

   Answer

   (b) Monera

2. Q2 · 1 mark · MCQExam level

   Plants with true roots, stems, leaves and vascular tissue but no seeds are
   (a) bryophytes
   (b) pteridophytes
   (c) gymnosperms
   (d) thallophytes

   Hint

   Ferns.

   Answer

   (b) pteridophytes

3. Q3 · 1 mark · Assertion-reasonExam level

   Assertion (A): Viruses are placed in Kingdom Monera.
   Reason (R): Viruses are acellular and active only inside host cells.
   (a) A and R are both true, and R explains A correctly.
   (b) A and R are both true, but R does not explain A.
   (c) A is true, R is false.
   (d) A is false, R is true.

   Hint

   No cell, no kingdom.

   Answer

   (d)

4. Q4 · 2 marks · Very short answerExam level

   Give two features each of Annelida and Arthropoda with one example.

   Hint

   Segments; jointed legs.

   Answer

   Annelida: soft, ring-segmented body; no legs; e.g. earthworm. Arthropoda: segmented body with jointed appendages and a hard exoskeleton; e.g. butterfly or crab.

5. Q5 · 2 marks · Very short answerHarder exam level

   List four ways in which classification is useful.

   Hint

   Library idea.

   Answer

   Makes study systematic; shows similarities, differences and relationships; helps identify and name new organisms; helps conservation of threatened species; gives a common language worldwide (any four).

6. Q6 · 3 marks · Short answerHarder exam level

   Why are bryophytes small and found only in damp places, while ferns can grow taller?

   Hint

   Transport tissue and reproduction.

   Answer

   Bryophytes have no vascular tissue and no true roots, so water cannot be carried far; they also need water for male cells to swim. Ferns have xylem and phloem and true roots, so they can carry water and food up a taller body, though they still need moisture for reproduction.

7. Q7 · 3 marks · Short answerHarder exam level

   Compare fish, amphibians and reptiles on body covering, breathing and eggs.

   Hint

   Scales, moist skin, dry scales.

   Answer

   Fish: scales; gills; eggs in water. Amphibians: moist skin without scales; gills as larvae, lungs and skin as adults; eggs in water. Reptiles: dry scales; lungs; shelled eggs laid on land.

8. Q8 · 3 marks · Short answerHarder exam level

   What are lichens? Why are they called bioindicators, and how do the two partners help each other?

   Hint

   Alga plus fungus.

   Answer

   Lichens are partnerships of an alga and a fungus. The alga photosynthesises and makes food; the fungus protects and holds water and minerals. They are sensitive to air pollution and change colour or disappear in polluted air, so they indicate air quality.

9. Q9 · 3 marks · Short answerHarder exam level

   A student finds a moving, green, single-celled organism in pond water that also feeds on organic matter in the dark. Which kingdom is it in? Why is it not a plant or an animal?

   Hint

   Euglena.

   Answer

   Protista (like Euglena). It is unicellular with a true nucleus; plants and animals are multicellular. Its mixed nutrition (photosynthesis in light, heterotrophic in dark) also does not fit either kingdom's fixed nutrition.

10. Q10 · 5 marks · Long answerHarder exam level

    Describe the hierarchy of classification using the pea plant, and explain what changes as you move from kingdom to species.

    Hint

    Seven levels.

    Answer

    Going down for the pea: Plantae (kingdom), Magnoliophyta (phylum), Magnoliopsida (class), Fabales (order), Fabaceae (family), Pisum (genus), sativum (species), giving Pisum sativum. Moving down, each group is part of the one above; the number of members falls and the number of shared features rises, until the species, whose members can interbreed and produce fertile offspring.

11. Q11 · 3 marks · Short answerHOTS / competency

    A natural forest has 40 kinds of trees, while a nearby plantation has only eucalyptus. A pest that attacks only eucalyptus arrives. Predict what happens in each, and explain why diversity gives stability.

    Hint

    Alternatives in the food web.

    Answer

    The plantation could be badly damaged, since every tree is a host and the pest spreads easily. In the forest only a few trees are hit, the pest spreads slowly between scattered hosts, and other species keep providing food and shelter. Many species give backups and barriers, so the ecosystem stays stable.

12. Q12 · 3 marks · Short answerHOTS / competency

    Viruses are sometimes described as being 'at the edge of life'. Give one feature that makes them seem living and two that make them seem non-living, and explain why they are left out of the five kingdoms.

    Hint

    Inside versus outside a host.

    Answer

    Living: they contain genetic material and make copies of themselves inside host cells. Non-living: they have no cell (no membrane, cytoplasm or organelles), and outside a host they are inactive and can even be crystallised. The five kingdoms are defined by cell features, so acellular viruses do not fit; this shows classification is a tool that changes with new knowledge.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1. 1.What are endemic species? Give one Indian example.Show answer

   Species found naturally only in one region, e.g. Nilgiri tahr.

2. 2.Name India's four biodiversity hotspot regions.Show answer

   Western Ghats, Indo-Burma (North-East), Himalaya, Sundaland (Nicobar Islands).

3. 3.Who proposed the five-kingdom classification and when?Show answer

   R. H. Whittaker, in 1969.

4. 4.What is the cell wall of fungi made of?Show answer

   Chitin.

5. 5.Why are bryophytes called amphibians of the plant kingdom?Show answer

   They live on land but need water for reproduction.

6. 6.Which plant group first has vascular tissue?Show answer

   Pteridophyta (ferns).

7. 7.What is a notochord?Show answer

   A flexible rod-like supporting structure along the back, present at least at some stage in chordates.

8. 8.Which phylum has jointed legs and an exoskeleton?Show answer

   Arthropoda.

9. 9.Who introduced binomial nomenclature?Show answer

   Carolus Linnaeus.

10. 10.Why are viruses not placed in any kingdom?Show answer

    They are acellular and can multiply only inside a living host cell.

Quick revision checklist

The night before the exam: can you do each of these without looking?

• ☐Can you define biodiversity, endemic species and hotspot?
• ☐Can you list seven criteria for classification?
• ☐Can you give the classification timeline with names and dates?
• ☐Can you fill the five-kingdom table from memory?
• ☐Can you name two features and one example of each plant group?
• ☐Can you name the eight invertebrate phyla in order with examples?
• ☐Can you compare the five vertebrate classes?
• ☐Can you write the seven hierarchy levels for the tiger?
• ☐Can you state three rules of binomial nomenclature?
• ☐Can you explain why viruses do not fit the five kingdoms?

Patterns in Life: Diversity and Classification: frequently asked questions