How do we classify invertebrates? SCIENCE CH. 1 L. 3 NOTES PG. 18 – 21

Vocabulary  Invertebrates – animals with no backbone

Invertebrate Facts  Most animals in the world are invertebrates  Some are too small to be seen  Largest can easily stretch the length of a basketball court (giant squid)

Mollusks  Soft body without bones  Some have shells for protection  Some have gills  Some absorb oxygen through the skin EExamples: SSnails SSlugs CClams SSquid

Worms  Belong to many different phyla  Can be very large or very small  Can range in size from microscopic to over 23 feet long  Examples  Flat worms  Flat and thin  Live in wet, damp places  Roundworms  Live in water or on land  Segmented worms  Example: Earthworm

Arthropods  Largest phylum of animals  Arthropod means “jointed feet”  Bodies are divided into separate segments

Dichotomous Key  Used to identify unknown organisms  Is used by answering a series of questions  A key can be made up for any group of organisms that is being observed  Birds, insects, trees, etc…