Vertebrates are a type of animal that includes fish, amphibians, reptiles, birds, and mammals. They all have a backbone made of vertebrae, which protects their spinal cord. Vertebrates are the largest group of animals on Earth and can be found in every corner of the globe.
There are over 60,000 species of vertebrates, making up more than 95% of all known animal species. The vast majority of these are fish, with around 32,000 species. Amphibians come in second with around 7600 species, followed by reptiles with just under 10 000 species. Birds make up the smallest group of vertebrates with only 9000 or so species.
Mammals are a special type of vertebrate because they have fur or hair covering their bodies. There are around 5500 mammal species on Earth today. Humans are the most widespread mammal and there are estimated to be over 7 billion of us!
The first vertebrates appeared on Earth during the Cambrian period around 520 million years ago. These early ancestors were small fish-like creatures that lived in shallow seas. Over time they evolved into the diverse group we see today.
Vertebrates have evolved many different adaptations to help them survive in different environments on land and in water. Some examples include:
– Fish have gills for breathing underwater
– Birds have feathers for flying