Primitive Critters

Porifera

Porifera - Body Plan

Cnidaria - body forms

Ctenophora

Platyhelminthyes

Parasitic Flatworms - Tapeworms Parasites have adaptations for attaching to their host as well as adaptations for evading the hosts immune defenses Tapeworms also have intermediate hosts. In humans the intermediate host may be a pig or cow. Fleas are the intermediate host of the dog tapeworm.

Parasitic Flatworms - Flukes Parasites often cause chronic debilitating diseases Their life cycles are often complex and may involve more than one host

Nemertae Also called proboscis worms. The extendable probocis is used to capture prey. Their body is much like a flatworm, but with an intestine, anus, and circulatory system.

Nematoda Nematodes, also called roundworms have a one way digestive system and a tube within a tube body design. The space between the two tubes is a type of body cavity called a pseudocoelom.

C. elegans

Trichina

Annelida - Segmented Worms

Playground Playmate?

Trochophore Larva

Mollusk Body Plan

Peripitus

Arthropoda

EARLY DEVELOPMENT