Each segment has a number of bristly hairs that earthworms use to help them move. Sometimes, if you run your fingers on the underside ventral of the earthworm, you can feel the setae. The glandular ring or saddle found on mature earthworms. After mating, the clitellum secretes a cocoon of eggs. Acknowledgement: Ross Gray. The top of the earthworm running from the anterior to the posterior. The underside of the earthworm running from the anterior to the posterior.
You can locate the ventral section by feeling for the setae. Acknowledgement: Adam Hart-Davis. The anus excretes wastes worm casts.
Acknowledgement: Robert Lamberts. Adaptation is an evolutionary process whereby an organism becomes increasingly well suited to living in a particular habitat. Natural selection results in helpful traits becoming more common in a Add to collection. The heart or aortic arches Y can be found over the esophagus just posterior to the pharynx.
Carefully tease away the tissues to expose the arches of the heart, the run across the worm. How many aortic arches can you count? Label the diagram use the letters next to the bold words above. The digestive system starts at the mouth. You will trace the organs all the way to the anus and identify each on the worm.
Find the mouth opening, the first part after the mouth is the pharynx, you will see stringy things attached to either side of the pharynx pharyngeal muscles.
You will find a two structures close to the clitellum. First in the order is the crop, followed by the gizzard. The gizzard leads to the intestine which is as long as the worm and ends at the anus. Locate the brain at the far anterior region of the worm.
It is very tiny and whitish colored. If you can't find it, it is probably because it was destroyed when you cut the worm. There are five pairs of aortic arches, which have the responsibility of pumping blood into the dorsal and ventral blood vessels.
Respiratory System Earthworms do not have lungs. They breathe through their skin. Body fluid and mucous is released to keep its skin moist. Earthworms therefore, need to be in damp or moist soil. These tissues enable an earthworm to detect light and not surface during the daytime where they could be affected by the sun.
Earthworm Reproduction Earthworms are hermaphrodites where each earthworm contains both male and female sex organs. The male and female sex organs can produce sperm and egg respectively in each earthworm. Although earthworms are hermaphrodites, most need a mate to reproduce.
During mating, two worms line up inverted from each other so sperm can be exchanged. The earthworms each have two male openings and two sperm receptacles, which take in the sperm from another mate. The earthworms have a pair of ovaries that produce eggs.
The clitellum will form a slime tube around it, which will fill with an albuminous fluid. The earthworm will move forward out of the slime tube. As the earthworm passes through the slime tube, the tube will pass over the female pore picking up eggs.
The tube will continue to move down the earthworm and pass over the male pore called the spermatheca which has the stored sperm called the spermatozoa.
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