I felt that this dissection was to help us learn and view the different organ systems of the earthworm to get a sense of the complicated structure of it. Even though that the worm is a simple and small organism, the internal organs and behaviour of the worm show the progression towards more advanced species in the world (ie: me) through complex organ development. This showed us the various structures of the worm, helped us identify each of the organs, and really gave us an overview (or deeper view) into (no pun intended) the worm. Overall, I believe the goal of this dissection is to exhibit a deeper understanding of earthworm anatomy, but also a preview of more complex (future) animals.
How it relates to what we are learning in class:
Since we are learning about annelids, and especially earthworms, this dissection made a stronger connection between the two. We were able to see all the different parts of the worm that the textbook told us were there, but never got to view. This allowed me to make a "road map" of the inside of the worm's body, knowing where all the organs are, and how each one is related to the other. I feel this is deeply interwoven with the classroom material. This is very useful in terms of understanding the basic concepts of the phylum Annelida, but also was a great way to practice making connection between knowledge and practical use.
Personal response:
I, personally, really enjoyed this dissection (although I enjoy every lab). I really liked that I had a chance to look at a real worm, and not a diagram on a textbook. I feel that this re-enforced the knowledge of annelids in my mind by making that mental connection between reality and knowledge. I have a sense of how small the organs are, and their respective colouring, location, and their bleeding point (how hard I poke it with the probe before it bleeds). I also saw the whole worm in a three dimensional view, which differed from my knowledge of earthworms. I learned from this that the nephridia are under the digestive tract, and also that the worm is flat on the ventral side, and round on the dorsal side. These little pieces of knowledge strengthens and fills gaps in my overall knowledge of earthworms and lead to a more sturdy and reliable source of information.
Questions:
1. What is the name of the pumping organs of the earthworm?
A: The aortic arches, arranged in parallel near the heart. These five hearts work together to pump blood through the worm's close circulatory system.
2. Trace the parts of the digestive tract through which food passes
A: The digestive system of the earthworm starts at the mouth of the worm, in to the pharynx, down to the esophagus, into the crop and gizzard, and travel through the intestine, and out the anus in excretion.
3. Which parts of the earthworm serve as its brain? How are these parts connected to the rest of the body?
A: The series of ganglia, masses of nerve cells, serve as the earthworms brain with an enlargement in each section. It is connected to the rest of the body by the ventral nerve cord, with a nerve collar just around the pharynx.
4.Which of the parts of the worm's body that you saw are included in the excretory system?
A: The anus passes solid wastes out in the form of feces (or castings). Nephridia, two in each segment, act as primitive bladders to remove wastes from its body fluids and excretes them.
5. How can you find out whether an earthworm eats soil?
A: During the dissection, I saw the worm's digestive tract to be somewhat brown, the colour of soil. Also, the castings of the worm would also contain undigested soil material, giving it the brown colour.
6. Among the earthworm's structural adaptations are its setae. How do you think the earthworm;s setae makes it well developed to its habitat?
A: The setae are hard, minute little spines that the earthworms can dig into the soil, to anchor itself from being dragged out of the ground. This adaptation works best when the setae are dug into the soil, meaning that this adaptation makes the earthworm well developed to its habitat
7. How is the earthworm's digestive system adapted for extracting relatively small amounts of food from large amounts of ingested soil?
A: The gizzard grinds up the soil and passes it on to the intestine to be digested. For this to be efficient, the gizzard and intestine must process much soil to supply the worm with its nutrients. The crop stores soil and will give a constant supply to the gizzard to ensure constant supply of nutrients from large amounts of soil.
8. Your dissection of the earthworm did not go beyond segment 32. What will you observe if you dissect the remainder of the worm to its posterior end?
A: I will be able to see the full intestine, more nephridia, and finally the anus. I will also be able to see the two main blood vessels and the ventral nerve cord.
9. During mating, two earthworms exchange sperm. Fertilization is external, and cocoons are produced from which the young eventually emerge. Refer again to steps 5 and 11. where you located the earthworm's reproductive organs. Use a reference to identify the role of each organ in the reproductive process of the earthworm. Summarize your findings.
A: Earthworms produce both eggs in the ovaries and sperm in the testes. The sperm is exchanged and received in the seminal receptacles through the sperm grooves. External fertilization occurs after the eggs and sperm have been released. The clitellum acts like a cocoon and wraps the eggs after it slips off the worm.
SOME PICTURES ARE FROM GOOGLE
I, personally, really enjoyed this dissection (although I enjoy every lab). I really liked that I had a chance to look at a real worm, and not a diagram on a textbook. I feel that this re-enforced the knowledge of annelids in my mind by making that mental connection between reality and knowledge. I have a sense of how small the organs are, and their respective colouring, location, and their bleeding point (how hard I poke it with the probe before it bleeds). I also saw the whole worm in a three dimensional view, which differed from my knowledge of earthworms. I learned from this that the nephridia are under the digestive tract, and also that the worm is flat on the ventral side, and round on the dorsal side. These little pieces of knowledge strengthens and fills gaps in my overall knowledge of earthworms and lead to a more sturdy and reliable source of information.
Questions:
1. What is the name of the pumping organs of the earthworm?
A: The aortic arches, arranged in parallel near the heart. These five hearts work together to pump blood through the worm's close circulatory system.
2. Trace the parts of the digestive tract through which food passes
A: The digestive system of the earthworm starts at the mouth of the worm, in to the pharynx, down to the esophagus, into the crop and gizzard, and travel through the intestine, and out the anus in excretion.
3. Which parts of the earthworm serve as its brain? How are these parts connected to the rest of the body?
A: The series of ganglia, masses of nerve cells, serve as the earthworms brain with an enlargement in each section. It is connected to the rest of the body by the ventral nerve cord, with a nerve collar just around the pharynx.
4.Which of the parts of the worm's body that you saw are included in the excretory system?
A: The anus passes solid wastes out in the form of feces (or castings). Nephridia, two in each segment, act as primitive bladders to remove wastes from its body fluids and excretes them.
5. How can you find out whether an earthworm eats soil?
A: During the dissection, I saw the worm's digestive tract to be somewhat brown, the colour of soil. Also, the castings of the worm would also contain undigested soil material, giving it the brown colour.
6. Among the earthworm's structural adaptations are its setae. How do you think the earthworm;s setae makes it well developed to its habitat?
A: The setae are hard, minute little spines that the earthworms can dig into the soil, to anchor itself from being dragged out of the ground. This adaptation works best when the setae are dug into the soil, meaning that this adaptation makes the earthworm well developed to its habitat
7. How is the earthworm's digestive system adapted for extracting relatively small amounts of food from large amounts of ingested soil?
A: The gizzard grinds up the soil and passes it on to the intestine to be digested. For this to be efficient, the gizzard and intestine must process much soil to supply the worm with its nutrients. The crop stores soil and will give a constant supply to the gizzard to ensure constant supply of nutrients from large amounts of soil.
8. Your dissection of the earthworm did not go beyond segment 32. What will you observe if you dissect the remainder of the worm to its posterior end?
A: I will be able to see the full intestine, more nephridia, and finally the anus. I will also be able to see the two main blood vessels and the ventral nerve cord.
9. During mating, two earthworms exchange sperm. Fertilization is external, and cocoons are produced from which the young eventually emerge. Refer again to steps 5 and 11. where you located the earthworm's reproductive organs. Use a reference to identify the role of each organ in the reproductive process of the earthworm. Summarize your findings.
A: Earthworms produce both eggs in the ovaries and sperm in the testes. The sperm is exchanged and received in the seminal receptacles through the sperm grooves. External fertilization occurs after the eggs and sperm have been released. The clitellum acts like a cocoon and wraps the eggs after it slips off the worm.
SOME PICTURES ARE FROM GOOGLE
Purpose-4/4
ReplyDeleteConnection to class-4/4
Personal Reflection-4/4
Conventions-4/4
Requirements-9/9
25/25