Class Oligochaeta notes

study these notes for the test

1. Phylum: AnnelidaPhylum: Annelida
Class: OligochaetaClass: Oligochaeta
By Mr. “The Man” ChapmanBy Mr. “The Man” Chapman

2. OligochaetaOligochaeta
EarthwormsEarthworms
OligosOligos
–fewfew
chaitechaite
–hairhair
Few hairsFew hairs

3. 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

4. OligochaetaOligochaeta
Oligochaetes have setae, but a lot Oligochaetes have setae, but a lot
fewer than polychaetes.fewer than polychaetes.

5. 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.

7. 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.

8. 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.

10. 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.

11. Cross Section of OligochaetaCross Section of Oligochaeta

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