ScienceCBSE Class 9 · Patterns in Life: Diversity and Classification

Plant and Animal Groups, Hierarchy and Binomial Nomenclature (Class 9)

Updated 17 October 2026 · Fact-checked

Plants fall into five groups: Thallophyta (no root, stem or leaf), Bryophyta (no vascular tissue), Pteridophyta (vascular, no seeds), Gymnosperms (naked seeds) and Angiosperms (flowers and seeds in fruits). Animals divide into non-chordates (Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata) and chordates (protochordates and the vertebrate classes fish, amphibians, reptiles, birds, mammals). The hierarchy runs Kingdom, Phylum, Class, Order, Family, Genus, Species, and every organism has a two-part Latin name (genus capitalised, species in lower case, in italics).

Going down the list, plants gain vascular tissue, then seeds, then flowers and fruits, which help them live on land.

Illustration drawn for QuestionBuddy.

Understand Plant and Animal Groups, Hierarchy and Binomial Names

Plantae in five groups. Thallophyta (algae; thallus = undifferentiated body): no root, stem or leaf, no transport tissue, no seeds, live in water (Spirogyra, Ulva, Chara). Bryophyta: small plants with rhizoids and simple stem- and leaf-like parts, no transport tissue, no seeds, need water for reproduction, so called the amphibians of the plant kingdom (moss, Marchantia). Pteridophyta: true roots, stems and leaves and transport tissue (xylem and phloem), no seeds, need water (ferns such as Marsilea and Pteris). Gymnosperms (gymnos = naked, sperma = seed): trees with needle- or scale-like leaves, naked seeds on cones, not in fruits, no water needed for reproduction (pine, cycas, deodar). Angiosperms (angeion = vessel): the most complex, flowers, seeds inside fruits, no water needed (mango, rose, grasses); divided by the number of cotyledons (seed leaves) in the seed into monocots (one cotyledon, usually parallel leaf veins, e.g. grasses) and dicots (two cotyledons, usually net-veined leaves, e.g. mango). The sequence shows plants solving life on land: vascular tissue for support and water transport, seeds for reproduction without water, flowers and fruits for pollination and dispersal.

Invertebrates (no notochord). Porifera (sponges): many pores, water flows through bringing food and oxygen, fixed, cellular level. Cnidaria (Hydra, jellyfish, coral): tentacles, one opening for food and waste, tissue level. Platyhelminthes (flatworms; tapeworm, liver fluke, Planaria): flat, bilaterally symmetrical, one opening, many parasitic with hooks and suckers. Nematoda (roundworms; Ascaris, hookworm): long, cylindrical, two openings (mouth and anus), separate sexes. Annelida (earthworm, leech): body in segments, muscles and a nerve cord. Arthropoda (insects, crab, spider): segmented body, jointed appendages, hard exoskeleton. Mollusca (snail, octopus, squid): soft body with head, muscular foot, often a shell. Echinodermata (starfish, sea urchin): spiny skin, marine, internal skeleton of calcium carbonate. The trend is towards more complex bodies. A kilogram of sponge can filter about 24 000 L of sea water a day.

Chordates. Protochordates (Amphioxus, Balanoglossus) have a notochord at some stage but no backbone. Vertebrates have a vertebral column that protects the spinal cord, with a skull protecting the brain. Fish: water, scales, gills, eggs laid in water. Amphibians: water and land, moist skin, gills as larvae and lungs and skin as adults, eggs in water (frog, toad). Reptiles: mostly land, dry scales, lungs, shelled eggs on land (lizard, snake, turtle). Birds: feathers, lungs, shelled eggs, warm-blooded. Mammals: hair or fur, lungs, mammary glands, most give birth, warm-blooded.

Hierarchy. 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 that share more features. For the tiger: Animalia, Chordata, Mammalia, Carnivora, Felidae, Panthera, P. tigris. For the pea: Plantae, Magnoliophyta, Magnoliopsida, Fabales, Fabaceae, Pisum, P. sativum. A species is a group of similar individuals that can interbreed and produce fertile offspring.

Binomial nomenclature (Linnaeus). Every organism has a two-part scientific name in Latin or Latinised form, genus then species. The genus starts with a capital letter and the species is all lower case; names are in italics when printed and underlined separately when handwritten. It avoids confusion between local names (bagh, puli, tiger, tigre). Examples: Panthera tigris (tiger), Panthera leo (lion, same genus), Mangifera indica (mango), Homo sapiens (human), Pisum sativum (pea), Nasikabatrachus sahyadrensis (purple frog).

Plant and Animal Groups, Hierarchy and Binomial Names: formulas and key facts

Plant groups in order: $T ha l l o p h y t a ∣ B r y o p h y t a ∣ P t er i d o p h y t a ∣ G y mn os p er m s ∣ A n g i os p er m s$
Invertebrate phyla: $P or i f er a ∣ C ni d a r ia ∣ P l a t y h e l min t h es ∣ N e ma t o d a ∣ A nn e l i d a ∣ A r t h r o p o d a ∣ M o l l u sc a ∣ E c hin o d er ma t a$
Vertebrate classes: $F i s h ∣ am p hibian s ∣ r e pt i l es ∣ bi r d s ∣ mamma l s$
Hierarchy: $K in g d o m \to P h y l u m \to C l a ss \to O r d er \to F ami l y \to G e n u s \to S p ec i es$
Binomial name: Genus (capital) + species (lower case), in italics or underlined separately

How to solve Plant and Animal Groups, Hierarchy and Binomial Names questions

Use this method to place a plant or animal in its group and to write names.

1For a plant: ask whether it has a root, stem and leaf, then vascular tissue, then seeds, then whether seeds are in fruits.
2For an animal: ask whether it has a notochord (chordate) or not; if not, use body plan (pores, tentacles, flat, cylindrical, segmented, jointed legs, soft body, spiny skin).
3For a vertebrate: use skin covering, breathing organs and the way it reproduces.
4For hierarchy, list the seven levels from kingdom downwards and note that numbers of members fall as you go down.
5For a scientific name, write genus with a capital, species in lower case, and italicise or underline each word separately.
6For survey data, convert counts to percentages of the total and check that they add to 100.

Plant and Animal Groups, Hierarchy and Binomial Names in real life

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.

Identifying a plant on a nature walk

Suppose a student finds a small green plant growing on a wet wall: it has thin stem-like and leaf-like parts, tiny root-like threads, no flowers, no seeds and no visible veins.

Name the group and give two reasons.

Try it first, then show the solutionSolution

It has rhizoids rather than true roots and simple stem- and leaf-like parts, with no vascular tissue.
It has no seeds or flowers and lives in a moist place because it needs water to reproduce.
So it is a bryophyte (like a moss), called the amphibian of the plant kingdom.

Answer: Bryophyta: rhizoids, no vascular tissue, needs water for reproduction.

Memory hook: Moss stays small and wet.

Writing a scientific name for a poster

Suppose a school poster about the Sahyadri hills must show the name of the purple frog and the mango tree, and the first draft reads 'nasikabatrachus Sahyadrensis' and 'Mangifera Indica'.

Correct the names and state the rules.

Try it first, then show the solutionSolution

Genus has a capital letter and species is in lower case: Nasikabatrachus sahyadrensis and Mangifera indica.
Both words are in italics when printed (or underlined separately when handwritten).
The name has two parts, genus then species, in Latin or Latinised form.

Answer: Nasikabatrachus sahyadrensis; Mangifera indica.

Memory hook: Capital genus, small species, slanted.

Tricks to remember Plant and Animal Groups, Hierarchy and Binomial Names

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

Plants: algae, moss, fern, cone, flower
Thallophyta (algae), Bryophyta (moss), Pteridophyta (fern), Gymnosperm (cone, naked seed), Angiosperm (flower and fruit).
Use it when: Ordering the five plant groups.
Pigs Can Play Nicely, And Also Make Eggs
Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata (first letters P, C, P, N, A, A, M, E).
Use it when: Ordering the eight invertebrate phyla.
King Philip Came Over For Good Soup
Kingdom, Phylum, Class, Order, Family, Genus, Species.
Use it when: Hierarchy order.
Fish Are Really Big Mammals
Fish, Amphibians, Reptiles, Birds, Mammals: the vertebrate classes.
Use it when: Listing classes of Chordata.

Plant and Animal Groups, Hierarchy and Binomial Names: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Three plant groups · 3 marks · Short answerBoard level

For each group name one feature and give one example: (a) Bryophyta, (b) Pteridophyta, (c) Gymnosperms.

Try it first, then show the solutionSolution

(a) Bryophyta: no transport tissue, rhizoids, need water for reproduction; example moss or Marchantia. (1)
(b) Pteridophyta: true roots, stems and leaves with xylem and phloem, no seeds; example fern (Marsilea, Pteris). (1)
(c) Gymnosperms: naked seeds on cones and needle-like leaves; example pine, cycas or deodar. (1)

Answer: Moss; fern; pine (with the features above).

Example 2: Correcting scientific names · 3 marks · Short answerBoard level

The following names are written wrongly: (a) panthera Tigris, (b) Homo Sapiens, (c) mangifera indica. Correct each and state the rules that were broken.

Try it first, then show the solutionSolution

(a) Panthera tigris: the genus needs a capital and the species must be in lower case. (1)
(b) Homo sapiens: the species name sapiens is in lower case. (1)
(c) Mangifera indica: the genus Mangifera needs a capital; both words in italics (or underlined separately by hand). (1)

Answer: (a) Panthera tigris; (b) Homo sapiens; (c) Mangifera indica.

Example 3: Counting down the hierarchy · 5 marks · Long answerHarder board level

A survey region has 4 orders, 12 families, 30 genera and 75 species of insects.
(a) Find the average number of families per order. (1)
(b) Find the average number of genera per family. (1)
(c) Find the average number of species per genus. (1)
(d) Find the average number of species per order. (1)
(e) Why do members of the same genus share more features than members of the same order? (1)

Try it first, then show the solutionSolution

(a) 12 ÷ 4 = 3 families per order. (1)
(b) 30 ÷ 12 = 2.5 genera per family. (1)
(c) 75 ÷ 30 = 2.5 species per genus. (1)
(d) 75 ÷ 4 = 18.75 species per order. Check: 3 × 2.5 × 2.5 = 18.75. (1)
(e) Each lower level is a smaller group inside the one above, formed by more specific shared features; the genus is closer to the species and has fewer members that share more features. (1)

Answer: (a) 3; (b) 2.5; (c) 2.5; (d) 18.75; (e) lower levels have fewer members sharing more features.

Example 4: Place the animals in their phyla and classes · 5 marks · Long answerHarder board level

Name the phylum or class of each and give a reason: (a) a worm with a flat body, hooks and suckers living in the intestine; (b) an animal with a soft body, muscular foot and shell; (c) a spiny-skinned marine animal; (d) an animal with moist skin, gills in the larva and lungs in the adult; (e) an animal with feathers. Also, how much water can 2.5 kg of sponge filter in 6 hours at the rate of 24 000 L per kg per day?

Try it first, then show the solutionSolution

(a) Platyhelminthes (tapeworm): flat, one opening, parasitic with hooks and suckers. (1)
(b) Mollusca (snail): soft body, muscular foot and often a shell. (1)
(c) Echinodermata (starfish): spiny skin, marine, internal skeleton of calcium carbonate. (1)
(d) Amphibia (frog): moist skin, gills as larva and lungs as adult. (e) Aves (birds): feathers. (1)
Sponge: per day 24 000 × 2.5 = 60 000 L; in 6 hours (¼ of a day) 60 000 ÷ 4 = 15 000 L. (1)

Answer: (a) Platyhelminthes; (b) Mollusca; (c) Echinodermata; (d) amphibians; (e) birds; sponge 15 000 L.

Example 5: A garden survey of plant groups · 4 marks · Case-basedHOTS / competency

A garden survey of 60 plants finds 12 mosses and liverworts, 8 ferns, 4 pines and cycads, and 36 flowering plants, of which 15 are monocots and 21 are dicots.
(a) Name the group of each type and find the percentage of each in the survey. (1)
(b) What percentage of the flowering plants are monocots? (1)
(c) What percentage of the plants have vascular tissue, and which groups are they? (1)
(d) Which plants need water for reproduction? Give the number and the percentage. (1)

Try it first, then show the solutionSolution

(a) Bryophyta 12 ÷ 60 × 100 = 20%; Pteridophyta 8 ÷ 60 × 100 = 13.3%; Gymnosperms 4 ÷ 60 × 100 = 6.7%; Angiosperms 36 ÷ 60 × 100 = 60%. Total 100%. (1)
(b) 15 ÷ 36 × 100 = 41.7%; the dicots are 58.3% (21 ÷ 36). (1)
(c) Ferns, gymnosperms and angiosperms have vascular tissue: 8 + 4 + 36 = 48, and 48 ÷ 60 × 100 = 80%. (1)
(d) Bryophytes and pteridophytes need water for reproduction: 12 + 8 = 20 plants, 20 ÷ 60 × 100 = 33.3%. (1)

Answer: (a) 20%, 13.3%, 6.7%, 60%; (b) 41.7%; (c) 48 plants, 80%; (d) 20 plants, 33.3%.

Where students lose marks in Plant and Animal Groups, Hierarchy and Binomial Names

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

Mistake: Writing scientific names without the correct case or italics.
Names are written like ordinary words.
Wrong working
Homo Sapiens
Right working
Homo sapiens (italics, or underline each word separately)
Do this: Capital for genus, lower case for species.
Usually costs: ½ to 1 mark.
Mistake: Mixing up gymnosperms and angiosperms.
Both are seed plants.
Wrong working
Angiosperms have naked seeds.
Right working
Gymnosperms have naked seeds on cones; angiosperms have seeds inside fruits.
Do this: Gymno = naked; angio = vessel.
Usually costs: 1 mark.
Mistake: Writing the hierarchy out of order.
The order of levels is not memorised.
Wrong working
Kingdom, Class, Phylum, Order, Genus, Family, Species
Right working
Kingdom, Phylum, Class, Order, Family, Genus, Species
Do this: Use a mnemonic.
Usually costs: 1 mark.
Mistake: Placing frogs with reptiles or bats with birds.
Habit or looks are used rather than body covering and breathing.
Wrong working
A bat is a bird because it flies.
Right working
A bat has fur and mammary glands: a mammal.
Do this: Use skin covering, breathing and reproduction.
Usually costs: 1 mark.
Mistake: Confusing the number of openings in flatworms and roundworms.
Both are worms.
Wrong working
Flatworms have two openings.
Right working
Flatworms have one opening; roundworms have two (mouth and anus).
Do this: Flat = one; round = two.
Usually costs: 1 mark.

Exam tips

Use a table for plant groups and for vertebrate classes: features in columns, groups in rows.
Give an example with every group you name.
Write scientific names with a capital for genus and lower case for species, and underline separately if you cannot use italics.
In 'identify the group' questions, use two features, not one.
In the hierarchy, state that numbers fall and shared features rise as you go from kingdom to species.

Practice questions on Plant and Animal Groups, Hierarchy and Binomial Names

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

Q1 · 2 marks · Very short answerBoard level
Name two features that ferns have but mosses lack, and say why they let ferns grow taller.
Hint
Think of transport tissue and true organs.
Answer
Ferns have true roots, stems and leaves and transport (vascular) tissue, xylem and phloem (1 mark). Xylem and phloem carry water and food over longer distances and give support, so ferns can grow taller than mosses (1 mark).
Q2 · 3 marks · Short answerHarder board level
Rewrite correctly the scientific names of the lion (panthera Leo), the human (homo sapiens) and the pea (pisum Sativum). Name the genus of each. State the three rules of writing.
Hint
Capital for genus only.
Answer
Panthera leo (genus Panthera), Homo sapiens (genus Homo), Pisum sativum (genus Pisum) (1 mark). Rules: the name has two parts, genus then species; genus begins with a capital letter and species is all in lower case; the name is in italics when printed or underlined separately when handwritten (2 marks).
Q3 · 2 marks · Assertion-reasonBoard level
Assertion (A): Ferns can grow taller than mosses. Reason (R): Ferns have xylem and phloem to carry water and food through the plant. Choose: (a) A and R both true, R explains A; (b) A and R both true, R does not explain A; (c) A true, R false; (d) A false, R true.
Hint
Which group first has vascular tissue?
Answer
(a). Pteridophytes have transport tissue to move water and food over greater height, whereas bryophytes lack it and stay small.
Q4 · 3 marks · Short answerHarder board level
Name the class of vertebrates described: (i) dry scales, lungs, shelled eggs on land; (ii) moist skin with gills as a larva; (iii) hair or fur and mammary glands. For each give one example. Also state one feature that all vertebrates share.
Hint
Use skin, breathing and reproduction.
Answer
(i) Reptiles, e.g. lizard (1 mark). (ii) Amphibians, e.g. frog (1 mark). (iii) Mammals, e.g. human or whale; all vertebrates have a vertebral column (backbone) that protects the spinal cord (1 mark).
Q5 · 4 marks · Case-basedHOTS / competency
A student collects four animals: P has a segmented body with a nerve cord and no legs; Q has jointed legs and a hard exoskeleton; R is flat with one body opening; S is a long cylinder with a mouth and an anus. (a) Name the phylum of each. (b) State the number of body openings in R and in S. (c) Which of the four phyla includes the insects, and why? (d) A kilogram of sponge filters 24 000 L of sea water a day; how much will 0.5 kg filter in 12 hours?
Hint
Use the table of phyla.
Answer
(a) P Annelida, Q Arthropoda, R Platyhelminthes, S Nematoda (1 mark). (b) R has one opening for food and waste; S has two (mouth and anus) (1 mark). (c) Arthropoda (Q): insects have a segmented body, jointed appendages and a hard exoskeleton (1 mark). (d) 24 000 × 0.5 = 12 000 L per day, so in 12 hours (half a day) = 6000 L (1 mark).

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.Which plant group has naked seeds?Show answer
Gymnosperms.
2.What hard outer covering protects an arthropod and reduces water loss?Show answer
The exoskeleton.
3.What is the genus of the tiger?Show answer
Panthera.
4.What is a species?Show answer
A group of similar individuals that can interbreed and produce fertile offspring.
5.How many body openings do roundworms have?Show answer
Two, a mouth and an anus.
6.Who introduced binomial nomenclature?Show answer
Carolus Linnaeus.

Plant and Animal Groups, Hierarchy and Binomial Names: frequently asked questions

Why do we need scientific names?

Local names differ from place to place (bagh, puli, tiger, tigre). A two-part Latin name is the same everywhere, so scientists worldwide understand which organism is meant.

Is a whale a fish?

No. It breathes with lungs, has some hair and mammary glands, and gives birth, so it is a mammal.

Which is the most diverse plant group?

Angiosperms.

What separates protochordates from non-chordates?

Protochordates have a notochord at some stage of life; non-chordates never do.

Are the lion and the tiger in the same genus?

Yes. Both are in the genus Panthera: Panthera leo and Panthera tigris.