“Little Rings”
Segmented worms
Tube worms
Leeches
Earthworms
 A segment is one of the small divisions on the surface of the
worm
 The average earthworm has about 100 segments.
 Segmented worms have a ONE WAY digestive system
 Annelinds blood moves through a “closed” circulatory system.
Which means blood is confined to blood vessels
 Earthworm need to remain moist at all times because they
absorb oxygen through their skin .
The Facts …
Body symmetryReproductionMovement-
Bilateral
Sexual
muscular contraction
Food- one-way digestive system – Scavengers
Why are Annelids good for our soil?
1. Break down organic matter
2. Make tunnels which help with aeration
and drainage
3. Circulate nutrients in soil
Intestine
Gizzard
Anus
Brain
Clitellum
Crop
Blood vessels
Hearts
Esophagus
Blood vessels
Nerve Chord
Mouth
Segments
Pharynx
Describe how each of these features
help earthworms move through the dirt.
1Bristles- “setae” small hairs on the skin
of worms, which helps them crawl
through the dirt.
2Mucus – outer covering of slime helps
them slide through the dirt and absorb
oxygen.
Miss. Styer’s Example Procedure:
1.
Set up tray at lab station.
2.
Place dry paper towel on one half of the tray.
3.
Wet a paper towel from the sink and on the opposite half of the tray.
4.
Get earthworm.
5.
Place earthworm on the center line between the wet and the dry
paper towel.
6.
Wait 3-5 min.
7.
Record the earthworm’s movements in observation table.
8.
Repeat steps 5 -7 at least two times.