The animal kingdom is divided into vertebrates and invertebrates. Mammals, birds, reptiles, amphibians, and fish are vertebrates. Insects are a type of invertebrate.
Animals
All animals, including people, have one thing in common – they eat other living things, either plants, or animals, or both. Almost all, except a few sea creatures, can move around. The beetle has muscles attached to its skeleton just like you do. Its skeleton is on the outside, however, while yours is on the inside.
What is an invertebrate?
The word invertebrate simply means not having a backbone. The “creepy-crawly” section of this book deals with the animals called invertebrates. Some of them have skeletons on the outside of their bodies, while some don’t have any bones at all.
What is a vertebrate?
Most of the large animals in the world are vertebrates. This means that they have a backbone, and most are made up of bones put together to make a skeleton. Mammals, birds, reptiles, amphibians, and fish are all vertebrates.
Creepy-crawlies
Creepy-crawlies, or invertebrates, make up over 95 per cent of all animals. But most of them are so small you don’t notice them. Some people think that there are millions of creepy-crawlies we do not even know about yet. Ants are insects, a kind of invertebrate.
Vertebrates
All vertebrates came from the same ancestor millions of years ago, but have changed, or evolved, into these four main groups. Creepy-crawlies Creepy-crawlies, or invertebrates, make up over 95 per cent of all animals. But most of them are so small you don’t notice them.
Fish: all fish live in the sea or in fresh water.
Reptiles and amphibians: these animals live on land or in water.
Mammals: most live on land and none can breathe underwater.
Birds: all birds have wings and most of them can fly.
Lions keep their sharp claws inside their toes to protect them, until they need to attack. Ants are insects, a kind of invertebrate.
