Animals without a backbone
Invertebrates do not have an external skeleton made of bone. Others have a hard outer shell. The most common invertebrates include:
Annelids * Anthropods * Echinoderms * Mollusks Protozoa
Many invertebrates have a fluid-filled skeleton (jellyfish and worms), whilst others have hard outer shells. (insects and crustaceans).
More than 98% of the animal species in the world are invertebrates.
Animals with a backbone
Invertebrates have an internal skeleton made of bone. Vertebrates include:
Amphibians * Fish * Reptiles * Birds * Mammals
Primates * Rodents * Marsupials
Most large land animals are vertebrates - even large sea animals. Although vertebrates represent only a small percentage of all animals, their size and mobility allow them to dominate their environment.
WARM BLOODED ANIMALS
Almost all mammals and birds are warm-blooded. They try to keep the inside of their bodies at a constant temperature. They do this by generating their own heat when they are in cooler environments, and by cooling themselves when they are in hotter environments.
Warm- blooded animals require much more food to survive.
COLD BLOODED ANIMALS
Almost all insects, amphibians and arachnids are cold-blooded. These creatures take on the temperature of their surroundings. When the environment is hot, they are hot and vice-versa. They are also much more active in warm environments and very sluggish in cold environments.
All the wonderful photographs on this site were collected via www.google.co.uk under the relevant animal category.
Please click on each photographs to be linked to the original source.