Animals and plants are placed in their kingdoms by their cells. Vertebrates split into five groups and arthropods into four by features you can see. Extended: all five kingdoms, ferns and flowering plants, monocots and dicots, and viruses, which belong to no kingdom at all.
Animals and plants are both multicellular, but plant cells have cellulose cell walls and chloroplasts while animal cells have neither. Vertebrates are grouped by skin covering, breathing and reproduction: fish, amphibians, reptiles, birds, mammals. Arthropods have jointed legs, a segmented body and an exoskeleton, and are grouped by counting legs, body parts and antennae: insects, arachnids, crustaceans, myriapods. Extended: every organism is in one of five kingdoms (animal, plant, fungus, prokaryote, protoctist); flowering plants are monocotyledons or dicotyledons; a virus is only genetic material in a protein coat.
Core: the features of the animal and plant kingdoms. Extended: all five kingdoms and viruses. Click each kingdom in the simulator and read the four boxes: nucleus, cell wall, chloroplasts and number of cells.
| Kingdom | Main features | Example |
|---|---|---|
| Animal | multicellular; cells have a nucleus but no cell wall and no chloroplasts; feed on organic substances made by other organisms | dog, human, bee |
| Plant | multicellular; cells have a nucleus, a cellulose cell wall and chloroplasts; make their own food by photosynthesis | maize, rose, fern |
| Fungus (Extended) | usually multicellular, made of thread-like hyphae (yeast is single-celled); cell walls of chitin; no chloroplasts; feed by secreting enzymes onto organic matter and absorbing the products | mushroom, mould, yeast |
| Prokaryote (Extended) | single-celled; no nucleus: circular DNA loose in the cytoplasm, plus plasmids; cell wall not made of cellulose | bacteria |
| Protoctist (Extended) | mostly single-celled, with a nucleus; some are animal-like, some plant-like with chloroplasts | Amoeba, Chlorella |
Fungi are not plants. A mushroom grows out of the ground, but fungal cell walls are made of chitin, not cellulose, and fungi have no chloroplasts, so they cannot photosynthesise.
Vertebrates are animals with a backbone. Explore each model, then classify the tricky animals in the quiz: think about the features, not where the animal lives.
| Group | Skin | Other main features |
|---|---|---|
| Fish | wet scales | fins; gills for gas exchange; lateral line senses movement in water; most lay eggs in water |
| Amphibians | moist, smooth, no scales | eggs without shells laid in water; young (tadpoles) have gills, adults have lungs and live on land |
| Reptiles | dry scales | lungs; eggs with soft, leathery shells laid on land |
| Birds | feathers | beak with no teeth; front limbs are wings; eggs with hard shells |
| Mammals | fur or hair | external ears (pinnae); whiskers; mammary glands make milk for the young; most give birth to live young |
Classify by features, not by habitat or lifestyle. A whale and a dolphin live in the sea but breathe with lungs and feed their young on milk: mammals. A penguin cannot fly but has feathers: a bird. A bat flies, but it has fur and its wings are skin: a mammal.
Arthropods are invertebrates with jointed legs, a segmented body and a hard exoskeleton. Choose a group and press Count the legs, then classify the animals in the quiz.
| Group | Legs | Body parts | Antennae | Example |
|---|---|---|---|---|
| Insects | 3 pairs | 3 (head, thorax, abdomen) | 1 pair | bee, butterfly, ant; usually 2 pairs of wings |
| Arachnids | 4 pairs | 2 (cephalothorax, abdomen) | none | spider, scorpion, tick |
| Crustaceans | more than 4 pairs | 2 (or more) | 2 pairs | crab, shrimp, woodlouse; exoskeleton hardened with calcium |
| Myriapods | 1 or 2 pairs on each segment | many similar segments | 1 pair | centipede, millipede |
Read whether a question gives legs or pairs of legs. Eight legs is four pairs (arachnid); eight pairs would point to a myriapod or crustacean. A spider is not an insect: it has four pairs of legs, two body parts and no antennae.
Four quick checks. Each correct answer earns XP and records this skill on your profile.
In the simulator, which two features does the plant cell have that the animal cell does not?
The simulator asks you to classify a penguin, which cannot fly. Which group is it in?
Count the legs on the spider in the simulator. Which set of features places it in the arachnids?
Extended: which statement about fungi is shown in the simulator?
Extended content. Turn each plant in the simulator and compare how it reproduces, its leaf veins, its flower parts and its cotyledons.
| Feature | Fern | Monocotyledon | Dicotyledon |
|---|---|---|---|
| Reproduces by | spores, in sori under the fronds | seeds | seeds |
| Flowers | none | parts in threes | parts in fours or fives |
| Leaves | large divided fronds | long and narrow, parallel veins | broad, network of branching veins |
| Cotyledons in seed | no seeds | one | two |
| Examples | bracken | grasses, maize, lilies | beans, roses, oak trees |
Unlocks once the four checks above are done. Worth more XP, written to IGCSE Paper 2 and Paper 4 standard.
A bat can fly. Which features show that it is a mammal and not a bird?
An animal has seven pairs of jointed legs and two pairs of antennae, and lives under logs on land. Which group does it belong to?
Extended: a plant has long narrow leaves with parallel veins and flowers with parts in threes. What else would you expect?
Extended: which structures are present in every virus?
This skill is now recorded on your profile. Keep the chain going.