Presence or absence of what feature distinguishes vertebrates from invertebrates?
heart
hair
scales
backbone
Animals are often identified as being either invertebrates or vertebrates. These are terms based on the skeletons of the animals. Vertebrates have a backbone made of bone or cartilage ( cartilage is a flexible supportive tissue. You have cartilage in your ear lobes. ). Invertebrates , on the other hand, have no backbone ( Figure below ). Invertebrates live just about anywhere. There are so many invertebrates on this planet that it is impossible to count them all. There are probably billions of billions of invertebrates. They come in many shapes and sizes, live practically anywhere and provide many services that are vital for the survival of other organisms, including us. They have been observed in the upper reaches of the atmosphere, in the driest of the deserts and in the canopies of the wettest rainforests. They can even be found in the frozen Antarctic or on the deepest parts of the ocean floor.