What Are Invertebrates?
Besidesbeingclassifiedintophyla, animalsarealsooftencharacterizedasbeinginvertebrates
or vertebrates. This is an informal classification term based on the skeletons of the animals.
Vertebrateshave a backbone of bone or cartilage, while invertebrates have nobackbone.
All vertebrate organisms are in the phylum Chordata, while invertebrates make up several
diverse phyla. As seen inFigure11.4, the invertebrates include the insects, the earthworms,
the jellyfish, the star fish, and a variety of other animals. In the next lessons we will discuss
some of phyla within the animal kingdom that contain invertebrates.
Figure 11.4: Snails are an example of invertebrates, animals without a backbone. ( 18 )Table 11.1:Phylum Examples
Porifera Sponges
Cnidaria Jellyfish, corals
Platyhelminthes Flatworms, tapeworms
Nematoda Nematodes, heartworm
Mollusca Snails, clams
Annelida Earthworms, leeches
Arthropoda Insects, crabs
Echinodermata Sea stars, sea urchinsLesson Summary
- Animals are multicellular, eukaryotic heterotrophs.