Vu-PAP Bio-2_March 23,2014- Taryn Tsujimoto
The earthworm, a member of the phylum Annelida, has a body that can grow to 6 to 7 inches long and ringed with segments called annuli that are covered in setae to have a grip on the soil.. The earthworm has a brown-red, earthy color to camouflage and hide from predators: birds, rats, toads, and fishermen. Since the earthworm has adapted to life underground, the worm has no eyes, has a mucus coating to help oxygen pass through the skin while it is in water or air, has a streamlined shape to move through the soil while sucking the soil into its mouth to extract the nutrients from decomposing matter.
- Understand the anatomy of the earthworm.
- Know the life cycle, role, and functions of the organs of the earthworm.
The First 31 Segments
Here is the worm my partner cut open for the dissection lab.
This is before we slit the body open with the scissors.
Eathworms are very useful to humans in many ways. Gardeners love that the worm replenishes the soil with nutrients that help the plants grow healthy. Fishermen use earthworms as bait on the hook for the fish to nibble on.
The Circulatory System
The Lumbricus terrestris has a closed circulatory system that involves 3 vessels: the dorsal vessel, ventral vessel, and aortic arches (the heart). Like other systems in the earthworm, the circulatory system goes through the entire length of the worm in a tube-like form. The worm's 5 aortic arches pump blood into the ventral and dorsal vessels, carrying the blood throughout the tube-like body, and contractions keep the blood moving in a single direction.
Did You Know...
- In South Africa, the longest earthworm ever recorded was 22 feet long.
- Earthworms can grow back the segments it has lost. Cut one in half, and soon enough, you'll have two worms good as new.
Giant Gippsland Earthworm