Invertebrate

From Wikipedia, the free encyclopedia

Invertebrate is a kind of animal that does not have a spinal column or backbone. It is the opposite of vertebrate, that means if an animal is not a vertebrate (fish, reptile, amphibian, bird, or mammal), it is an invertebrate. Some examples of invertebrate animals are:

• Arthropods (arachnids, crustaceans, insects, and others);
• Molluscs (octopuses, squids, and others);
• Echinoderms — starfish, sea urchins, sea cucumbers
• Porifera — sponges
• Cnidarians — jellyfish
• Platyhelminthes — flatworms
• Nematoda — roundworms
• Annelida — segmented worms
• Bryozoa — sea mats or moss animals (occasionally resemble corals)
• Rotifers — tiny "wheel animals", which live in habitats such as pond water.

Insects have no bones, but they have a skeleton on the outside of their bodies that scientists call an exoskeleton. It is like our skin, only it is hard.

Also there are "Crustaceans" which has a chalky outer skeleton. And they mostly live in water. Such as crabs!

Sharks and related skates and rays are vertebrates with cartilage instead of bones.