Annelid Dissection

         On Friday I got to experience my first dissection in Biology 11. We were assigned partners and given a procedure package in which we were to follow while disecting the annelid. At first cutting open a former living creature somewhat disturbed me, however after I sliced the thin skin of the earthworm I was fascinated to discover the interior structures of this organism. Previous to this lab we had been learning about annelids in class and to follow up on the notes we were able to dissect this creature for a better understanding of the information in how earthworms live. The purpose of this assignment was to further learn about the internal and external structures of this organism and with a hands on experience like dissecting, this was achieved. This independent investigation in a neat learning environment helped me comprehend the key information in a precise way. I have learned to love dissecting, I think it is great benefit to our classroom learning and I hope to do this again soon!

1.The pumping organs of the circulatory system in an earthworm are the five aortic arches, or hearts.

via: Jordan Cameron

2. Food enters the mouth, which then goes to the pharynx, enters between pharynx and the crop - esophogus, broken down in the gizzard, then moves through intestine where it's body absorbs nutrients, then the waste is excreted through the anus.

3. Unfortuantely I couldn't get a close up of the brain. The earthworm's brain  is the ganglia above the pharynx (celebral ganglion) and it's connected to the rest of the body through the ventral nerve cord.

 

4. This picture is clearly representing the anus. The anus and the nephridia is the part of the excretory system that we saw when dissecting this earthworm.

5. This picture of the intesting clearly shows that the insides are brown. To find out if the worm eats soil Gabi and I cut the intestine open. We found exactly what was predicted.. Soil!

                             6. Setae help the earthworm move through the soil. Hardly any movement would occur without the help of the setae, also assist in feeling of soil and vibrations.

7. This is a clear picture of the earthworm's digestive tract. The earthworm takes in a mixture of soil and organic matter through its mouth. After moving through the pharynx and esophogus it's then temporarily stored in the corp. After this process in completed the mixture is ground up in the gizzard and then digested and absorbed by the intestine. The undigested material are excreted through the rectum and anus and become fertilizer.

8. After segment 32 Gabi and I observed the intestine and the anus, nephridia and blood.



9. Earthworms have bothe eggs and sperms making them hermaphroditic. Eggs exit through the female genital pores and the sperm goes through the male genital spores. When mating earthworms attach on to eachother and send sperm into one another. Earthworms have a clitellum which produces a sticky ring for fertilization.