Worm Notes

Metamerism

term that refers to developing a body of many segments that are similar in form.

Setae

tiny bristly structures that increase surface area and aid in gripping.

Parapodia

larger appendages that increase surface area to accommodate setae.

Class Polychaeta

Numerous parapodia and setae, Bristle worms, “feather duster” worms, etc.

Class Hirudinae

No parapodia or setae, Leeches

Class Oligochaeta

Have setae along their ventral side, earthworms

Countershading

pigmentation pattern where the organism is dark on top and lighter on the bottom.

Phylum Nematoda

Roundworms

What animals are the most numerous on the planet?

Roundworms are the most numerous

Alimentary Canal

mouth, pharynx, esophagus, intestine, anus

nervous system

ganglionic brain

where are the nerves

ventral side