The five kingdoms and the vertebrate groups

Last time

Before we start: last time, in Species, binomial names and the five kingdoms, you learned these points. Here they are again on one card. Keep them in mind, because today builds on them.

Sorting all of life

There are millions of kinds of living things, from bacteria to blue whales. Biologists sort them first into five very large groups called kingdoms. Then, inside the animal kingdom, the animals with backbones are sorted into five vertebrate groups.

The five kingdoms

The five kingdoms are animals, plants, fungi, prokaryotes and protoctists. Prokaryotes are the bacteria. Their cells have no nucleus. All the other four kingdoms have cells with a nucleus.

Animals and plants

Animals are multicellular. Their cells have a nucleus but no cell wall and no chloroplasts. They feed on organic substances made by other organisms. Plants are multicellular. Their cells have a nucleus, a cellulose cell wall and chloroplasts. They make their own food by photosynthesis. Plants also store carbohydrate as starch or sucrose.

Fungi, prokaryotes, protoctists

Fungi have a nucleus and a cell wall made of chitin, not cellulose. They do not photosynthesise. They feed by digesting food outside their cells. Prokaryotes are single cells with no nucleus. Their DNA is a loop in the cytoplasm, and they have a cell wall. Protoctists are mostly single-celled with a nucleus. Some are like animals, such as Amoeba, and some like plants, such as algae.

Three cells, three kingdoms

Use three questions. Is there a nucleus? If not, it is a prokaryote. Is there a cell wall? An animal cell has none. Are there chloroplasts? A plant cell has them, a fungus cell does not.

Vertebrates

Vertebrates are animals with a backbone. There are five groups: mammals, birds, reptiles, amphibians and fish. Mammals have fur or hair, external ears called pinnae, and mammary glands that make milk. Most give birth to live young. Birds have feathers, a beak, two wings and two legs, and they lay eggs with hard shells.

Vertebrates

Reptiles have dry scales on their skin and lay eggs with soft, leathery shells, on land. Amphibians have moist skin with no scales. They lay jelly-coated eggs in water, and the young, tadpoles, live in water. Fish have wet scales, gills to breathe in water, and fins to swim.

The vertebrate table

Two features sort them fastest. Look at the skin covering. Then look at the eggs. Feathers and hard eggs mean a bird. Dry scales and soft eggs mean a reptile.