Plant or animal? The vertebrates — answer key

1. VQ1 · Practice

Options as numbered on the pupil sheet: 1 — Animals only; 2 — Plants only; 3 — Both kingdoms.

Model answer. Both kingdoms are made of many cells, and the cells of both have a nucleus. Plant cells have a cell wall made of cellulose and chloroplasts, so plants make their own food by photosynthesis. Animal cells have a membrane but no wall and no chloroplasts, so animals must feed on organic substances made by other living things.

A full answer includes

• Made of many cells: both.
• Cells with a nucleus: both.
• Cell walls made of cellulose: plants only.
• Chloroplasts: plants only.
• Make their own food by photosynthesis: plants only.
• Cells with a membrane but no cell wall: animals only.
• Feed on organic substances made by other living things: animals only.

Also accept

• many cells: both; nucleus: both; cellulose walls: plants; chloroplasts: plants; photosynthesis: plants; membrane but no wall: animals; feed on organic substances made by others: animals

Watch for

• “Only plants are made of cells.” — Both kingdoms are made of many cells; the difference is what the cells have: walls and chloroplasts in plants.
• “Animal cells have a cell wall too.” — Animal cells have a cell membrane only; a wall made of cellulose is a plant feature.

2. VQ2 · Practice

Model answer. b. Its cells have a membrane but no cell wall and no chloroplasts, so it cannot make its own food: it catches small animals with its tentacles and digests them. Those are animal-kingdom features. Plants move parts of themselves too (a), some plants such as sea grasses live in the sea (c), and pondweed is a soft plant (d).

A full answer includes

• b: no cell walls, no chloroplasts and feeding on other organisms are animal-kingdom features; staying in one place is not a kingdom feature.

Also accept

• b

Watch for

• “It stays in one place, so it must be a plant.” — Many animals stay fixed to one spot. Look for cell walls, chloroplasts and how the organism gets its food.

3. VQ3 · Practice

Options as numbered on the pupil sheet: 1 — Fur or hair; feed their young on milk; most have ear flaps; 2 — Feathers, a beak and wings; lay eggs with hard shells; 3 — Dry skin with scales; lay eggs with rubbery shells; 4 — Moist skin with no scales; lay soft eggs in water; 5 — Scales and fins; breathe with gills.

Model answer. Mammals have fur or hair and feed their young on milk; most also have ear flaps. Birds have feathers, a beak and wings, and lay eggs with hard shells. Reptiles have dry skin with scales and lay eggs with rubbery shells. Amphibians have moist skin with no scales and lay soft eggs in water. Fish have scales and fins and breathe with gills.

A full answer includes

• Mammals: fur or hair; feed their young on milk; most have ear flaps.
• Birds: feathers, a beak and wings; eggs with hard shells.
• Reptiles: dry skin with scales; eggs with rubbery shells.
• Amphibians: moist skin with no scales; soft eggs in water.
• Fish: scales and fins; breathe with gills.

Also accept

• mammals: fur, milk (most have ear flaps); birds: feathers, beak, wings, hard-shelled eggs; reptiles: dry scaly skin, rubbery-shelled eggs; amphibians: moist skin, no scales, soft eggs in water; fish: scales, fins, gills

Watch for

• “Reptiles and fish are one group, because both have scales.” — Fish have scales and fins and breathe with gills; reptiles have dry scaly skin and breathe air.
• “Amphibians have scales.” — Amphibian skin is moist with no scales; dry skin with scales is a reptile feature.

4. VQ4 · Practice

Model answer. c. The penguin has feathers, a beak and wings, even though its wings are stiff flippers, and it lays eggs with hard shells: all bird features. Flying is not one of them. Its flippers are wings, not fins (a), it has no fur and does not feed its young on milk (b), and where it lives does not decide its group (d).

A full answer includes

• c: feathers, a beak, wings (its flippers) and eggs with hard shells are bird features; flying is not.

Also accept

• c

Watch for

• “A penguin is not a bird, because it cannot fly.” — Flying is not a bird feature: feathers, a beak, wings and eggs with hard shells are, and the penguin has all of them.
• “An animal that lives on land and in water is an amphibian.” — Amphibians are placed by moist skin with no scales and soft eggs laid in water, not by where they live.

5. VQ5 · Practice

Model answer. b. Fur and milk for the young are mammal features, and most mammals also have ear flaps, as the bat does. Birds have feathers and a beak, and the bat has neither (a). Skin on the wings does not make it a reptile, which has dry skin with scales (c). The bat is not between two groups (d): its features all point to the mammals.

A full answer includes

• b: fur and feeding the young on milk are mammal features (most mammals also have ear flaps); wings alone do not make a bird.

Also accept

• b

Watch for

• “A bat is a bird, because it has wings.” — Birds have feathers and a beak. A bat has fur and ear flaps and feeds its young on milk, so it is a mammal.

6. VQ6 · Practice

Model answer. (a) The newt has smooth, moist skin with no scales; the lizard has dry skin covered in rows of small scales. (b) So the newt is an amphibian and the lizard is a reptile. (c) The newt lays soft eggs in water, where its tadpoles live; most lizards lay eggs with rubbery shells on land.

A full answer includes

• (a) Newt: smooth, moist skin with no scales; lizard: dry skin covered in scales.
• (b) Newt: amphibian; lizard: reptile.
• (c) Newt: soft eggs, laid in water; lizard: most lay eggs with rubbery shells, on land.

Also accept

• (a) newt moist, no scales; lizard dry with scales; (b) newt amphibian, lizard reptile; (c) newt soft eggs in water; lizard rubbery-shelled eggs on land

Watch for

• “A lizard is an amphibian, because it looks like a newt.” — Look at the skin: dry with scales is a reptile; moist with no scales is an amphibian.
• “Reptiles lay their eggs in water.” — Most reptiles lay eggs with rubbery shells on land; soft eggs laid in water are an amphibian feature.

7. VQ7 · Practice

Model answer. The dolphin and the otter feed their young on milk, so they are mammals: 2. The puffin and the herring gull have feathers, a beak and wings: 2 birds. The cod and the salmon have scales and fins and breathe with gills: 2 fish. The sea turtle has dry skin with scales and lays eggs with rubbery shells: 1 reptile.

Checked automatically

• Mammals: 2 (exact value)
  • Common wrong answer 1 : The dolphin has no fur, but it breathes air and feeds its calf on milk: it is a mammal, like the otter.
• Birds: 2 (exact value)
• Fish: 2 (exact value)
  • Common wrong answer 3 : The dolphin has fins, but no scales and no gills, and it feeds its calf on milk: it is a mammal.
• Reptiles: 1 (exact value)

A full answer includes

• Mammals: 2 (dolphin, otter).
• Birds: 2 (puffin, herring gull).
• Fish: 2 (cod, salmon).
• Reptiles: 1 (sea turtle).

Also accept

• mammals 2; birds 2; fish 2; reptiles 1

Watch for

• “Every animal with fins is a fish.” — The dolphin has fins, but no scales and no gills, and it feeds its calf on milk: it is a mammal.
• “A sea turtle is an amphibian, because it lives in the sea and on land.” — Dry skin with scales and eggs with rubbery shells are reptile features.

8. VQ8 · Practice

Model answer. The biologist looks at features, not at where the organism lives. Under the microscope, each pondweed cell has a cell wall made of cellulose and many chloroplasts. In the light, pondweed makes its own food by photosynthesis: bubbles of oxygen rise from its leaves. Those are plant-kingdom features.

A full answer includes

• Its cells have cell walls (made of cellulose) and chloroplasts.
• It makes its own food by photosynthesis (in the light it gives off bubbles of oxygen).

Also accept

• cell walls (cellulose) and chloroplasts; makes its own food by photosynthesis; habitat does not decide the kingdom

Watch for

• “A plant must grow in soil and have a hard stem.” — Where an organism lives and how stiff it is are not kingdom features: look at the cells and how it gets its food.

9. VT1 · Apply

Model answer. (a) A fish has scales and fins and breathes with gills. The whale has no scales and no gills: it breathes air at the surface. It also feeds its calf on milk, which no fish does. (b) The whale is a mammal: a mother whale makes milk in her mammary glands and feeds her young on it. Where it lives and how it swims do not decide its group.

A full answer includes

• (a) Any two: no scales; no gills (it breathes air); it feeds its young on milk.
• (b) Mammal: it feeds its young on milk made in mammary glands.

Also accept

• (a) two of: no scales; no gills / breathes air; feeds young on milk; (b) mammal: milk from mammary glands

Watch for

• “A whale is a fish, because it lives in water and has fins.” — Where an animal lives and how it swims are not group features: no scales, no gills and milk for its young make it a mammal.
• “A mammal must have fur that you can see.” — Fur is usually the first mammal feature to see, but feeding the young on milk is a feature every mammal shares.

10. VT2 · Apply

Model answer. (a) The flytrap is made of many cells with cellulose cell walls, and its green leaves have chloroplasts: it makes its own food by photosynthesis. (b) The insects add mineral ions that its boggy soil lacks; the flytrap still makes its food by photosynthesis. An animal has no cell walls and no chloroplasts, and cannot make its own food at all.

A full answer includes

• (a) Its cells have cell walls (cellulose) and chloroplasts; it makes its own food by photosynthesis (its leaves are green).
• (b) It still makes its food by photosynthesis; the insects add mineral ions that its soil lacks. A kingdom is decided by the cell features and how the organism makes or gets its food, not by one habit.

Also accept

• (a) cell walls (cellulose), chloroplasts, makes its own food by photosynthesis; (b) insects add mineral ions; it still photosynthesises; animals have no walls or chloroplasts

Watch for

• “Anything that digests animals is an animal.” — The flytrap digests insects for mineral ions, but its cells have walls and chloroplasts and it makes its own food: it is a plant.

11. VT3 · Apply

Model answer. (a) The platypus is a mammal. (b) It has fur, and the mother feeds her young on milk: only mammals have these. Its bill looks like a beak and it lays eggs, so people may think of a bird or a reptile, but it has no feathers, no wings and no scales. It has no ear flaps, but fur and milk decide its group.

A full answer includes

• (a) Mammals.
• (b) Fur and feeding the young on milk are mammal features that no other group has.
• (b) The duck-like bill could suggest a bird, and laying eggs could suggest a bird or a reptile; but it has no feathers and no scales, and the missing ear flaps do not outweigh fur and milk.

Also accept

• (a) mammal; (b) fur and milk are mammal-only features; the bill and egg-laying suggest a bird or reptile, but no feathers or scales

Watch for

• “An animal that lays eggs cannot be a mammal.” — Most mammals do not lay eggs, but the platypus has fur and feeds its young on milk, so it is a mammal.
• “Its bill is a beak, so it is a bird.” — Birds have feathers and wings as well as a beak; the platypus has fur and no feathers.