Animals can be grouped by body plans — Biology, 7–10 years
A backbone is one useful clue for sorting animals, but animals without backbones can have other strong body structures.
A backbone is a useful clue
Scientists group animals by features they share, not by where they live or how big they are. One important split is between vertebrates, which have a backbone inside the body, and invertebrates, which do not. Invertebrates include insects, worms, snails and octopuses.
Why sort animals?
There are millions of animal species, so naming and comparing each one without a system would be confusing. Grouping by shared body features makes it easier to identify an unfamiliar animal and ask what it may have in common with known animals. This system grew from careful observation and comparison.
Three animals, one clue
Sort three animals by looking for a backbone: 1) a pigeon has bones and a backbone, so it is a vertebrate; 2) an earthworm has no backbone, so it is an invertebrate; 3) a snail also has no backbone, so it is an invertebrate. The groups depend on the feature, not on flying, crawling or having a shell.
No backbone does not mean no skeleton
It is understandable to think that an invertebrate must be soft and without support, because earthworms have no hard bones. But many invertebrates have a skeleton: a beetle has a hard outer covering, and a snail has a shell. The word only says that there is no backbone.
Sorting animals in real life
A wildlife guide uses body clues to identify an animal seen on a walk, even when its name is unknown. Museums and zoos organise information in groups so visitors can compare animals more easily. A vet may also use shared body structures when thinking about how an animal’s body works.
Keep exploring
Other languages
Loading MyLeoNes™…