Animals with an internal skeleton made of bone are called vertebrates. Vertebrates include: primates, such as humans and monkeys; amphibians; reptiles; birds; and, fish.Although vertebrates represent only a very small percentage of all animals, their size and mobility often allow them to dominate their environment.
Of the million or more animal species in the world, more than 98% are invertebrates. Invertebrates don't have an internal skeleton made of bone. Many invertebrates have a fluid-filled, hydrostatic skeleton, like the jelly fish or worm. Others have a hard outer shell, like insects and crustaceans. There are many types of invertebrates. The most common invertebrates include the protozoa, annelids, echinoderms, mollusks and arthropods. Arthropods include insects, crustaceans and arachnids.
Invertebrates
 |  |  |  |
| Portoza | Annelids | Mollusks | Echinoderms |
 |  |  | |
| Crustaceans | Arachnids | Insects | |
Vertebrates
 |  |  |  |
| Fish | Amphibians | Reptiles | Birds |
 |  |  | |
| Mammals | Primates | Rodents | |
 |  |  | |
| Marsupials | Whales and Dolphins | Seals |
I read somewhere that an easy way to distinguish is this: One that wags its tail up and down is a mammal and that which does sideways is a fish. I'm not sure if this maxim works !!
ReplyDelete