|
Amphibians are a group of vertebrates which evolved from lobe-finned fishes. Most amphibians spend at least part of their life-cycles in watery environments.
|
Birds are warm-blooded vertebrates distinguished by bodies and wings covered in feathers. Most birds are able to fly and all reproduce by laying eggs.
|
Fish are aquatic vertebrates with bodies covered with scales, two sets of paired fins and gills. Fish are generally classified as “bony” and “cartilaginous."
|
Invertebrates make up 97% of all animals on Earth. Invertebrates lack backbones and therefore the category includes all animals that are not vertebrates.
|
Mammals are warm-blooded vertebrates at least partially covered by fur or hair. Females give live birth and nurse them by secreting milk.
|
Reptiles are cold-blooded vertebrates descended from amphibians. Their bodies are protected by scales and reproduce by laying eggs.
|
