class oligochaeta notes

Phylum: AnnelidaPhylum: AnnelidaClass: OligochaetaClass: Oligochaeta

By Mr. “The Man” ChapmanBy Mr. “The Man” Chapman

OligochaetaOligochaeta EarthwormsEarthworms OligosOligos

– fewfew chaitechaite

– hairhair Few hairsFew hairs

OligochaetaOligochaeta About 3,000 About 3,000

speciesspecies Mostly terrestrial Mostly terrestrial

and freshwater.and freshwater.

Earthworms have Earthworms have poorly developed poorly developed heads and setae heads and setae

OligochaetaOligochaeta Oligochaetes have setae, but a lot Oligochaetes have setae, but a lot

fewer than polychaetes.fewer than polychaetes.

EarthwormsEarthworms Earthworms live Earthworms live

under the soil under the soil surface and feed surface and feed on decomposing on decomposing organic material. organic material.

As they burrow, As they burrow, they swallow soil they swallow soil and they digest the and they digest the organic material in organic material in soil.soil.

OligochaetesOligochaetes At night, they move to the surface to At night, they move to the surface to

pass the soil as a waste. pass the soil as a waste.

Earthworms are ecologically important. Their burrows allow air to make its way into the soil where it can support plants’ root cells as well as other fossorial animals.

In a year, earthworms will stir the top 12 inches of soil in a typical field.

EarthwormsEarthworms ClitellumClitellum – – is non-segmented section

of the body (looks like a band aid) near the head in earthworms and leeches, that secretes a sac with eggs.

Cross Section of OligochaetaCross Section of Oligochaeta

The largest earthworm species grow to 3 feet in length and it stretches to 9 feet when crawling.