Evolutionary Trends

Animal with no tissues (parazoa):  Schypha sp

Animal with tissues (Metazoa):  Ascaris sp.

Example of organisms with radial symmetry:

Starfish                        Starfish                            Sea Urchin                                    Hydra sp.


Sea Anemone


Examples of organisms with bilateral symmetry:

Earthworm                    Salamander                Frog                                        Salmon


Example of an animal with no body cavity (Acoelomate):  Dugesia sp.


Example of an Animal with a false body cavity (Psuedocoelomate):  Ascaris sp.

Example of and Animal with a true body cavity (Eucoelomate):  Earthworm