Platyheminthes

Common Animals:

MEI's:

Examples:

Time Arose:

# of Species:

Common Animals:

Flatworms

MEI's:

1. Bilateral Symmetry

2. Ladder style nervous system

3. Triploblastic

4. Acoelomate

5. Elaborate gastrovascular cavity

Examples:

1. Parasites

2. Tubellerians

Time Arose:

1. 550 MYA

# of Species:

1. 20,000, mostly aquatic

Nematoda

Common Animals:

MEI's:

Examples:

Time Arose:

# of Species:

Extra Information:

Common Animals:

1. Roundworms

MEI's:

1. Complete disgestive system

2. Pseudocoelom

Examples:

1. None

Time Arose:

1. 550 MYA, after Platyheminthes

# of Species:

1.25,000 - 8,000,000 species (includes C. elegans)

Extra Information:

1. Most damaging crop pests

2. Important for soil decomposition

Mollusca

MEI's:

1. True coelom

2. Unique body plan

(foot, visceral mass, mantle, shell, gills, circulatory system, radula)

Classes that compose this phyla:

1. Gastropoda

2. Bivalvia

3. Cephalopoda

Total # of species:

100,000 living and 100,000 extinct species

Time:

Arose 550 MYA

-Earthworms

-Few setae (bristles)

-Mostly terrestial

-Many setae

-Parapodia for locomotion and gas exchange

-Mostly marine

-Fan worms are the best example