I N V E R T E B R A T E S
-
animals
without backbones...
Invertebrates are animal species that
do not develop a vertebral column. This in effect includes
all animals apart
from the subphylum
Vertebrata.
Familiar examples of invertebrates include insects, worms, clams, crabs, octopus,
snails,
and starfish.
Taxonomically
speaking "invertebrate" is no more than a term of convenience. The
vast majority of animal species are invertebrates, since only about 3% of
animal species
include a vertebral column in their anatomy.
In other words all animals except those in the chordate
subphylum Vertebrata (fish, amphibians,
reptiles,
birds, and mammals) are regarded
as invertebrates. What is more, many an individual invertebrate taxon has a
greater number and variety of species than the entire subphylum Vertebrata.
Classification of Invertebrates
Invertebrates can be classified in 8 main phyla: · Porifera - the sponges · Cnidaria - the hollow-bodies animals · Platyhelminthes - the flatworms · Nemathelminthes - the unsegmented roundworms · Annelida - the segmented roundworms · Arthropoda - the joint-legged animals · Mollusca - the soft-bodied animals · Echinodermata - the spiny-skinned animals |
|