Phylum annelida
Characteristics:
- first to have a true coelom, mesoderm on both skin and gut
- Protostomes, blastopore becomes mouth in development
- first to have a circulatory system (closed).
- respiration through skin
- repeating segments (after clitellum) (earthworm)
- hermaphroditic
- first appendage development (polychaeta) as parapodia
lab
1. what is the name of the earthworm's 'pumping organ': The earthworm's pumping organ(s) are the aordic arches. the arches act as hearts to pump blood around the earthworm's circulatory system. (there are 5 aordic arches)
2. trace the earthworm's digestive tract: the Earthworm eats dirt with it's mouth (once the prostomium opens), the dirt goes through the esophagus and into the crop. here the food sits until the earthworm is ready to digest it. when its ready, the dirt is pushed into the gizzard where its 'ground up' by the muscles around the crop contracting. after being 'ground up' by the gizzard, the dirt is pushed into the intestine, here enzymes break down the parts in the soil that the earthworm eats and absorb the broken down particles. the remaining dirt is pushed through the intestine and out the anus.
3. what parts of the earthworm serve as its brain? what connects the brain to the rest of the body: the nerve collar serves as the earthworm's brain, the ventral nerve cord connects it to the rest of the body.
4. Which of the parts of the earthworms body that you saw are included in the excretory system: we saw the nephridia during the earthworm dissection, these excretory organs are in charge of liquid waste. the fluid inside the previous section is brought to the nephridium and whatever nutrients that are in it are absorbed and sent via the bloodstream to parts of the worm's body. the rest of the liquid is excreted out the side of the worm.
5. how can you find out whether an earthworm eats soil: cut open the worm's digestive tract. (???) or watch a live worm eat dirt.
6. how do the earthworm's setae make it better adapted to its environment: the setae, being tiny little 'legs' help the earthworm move through tiny passages in the ground. because they are so small, they don't get in the way as the worm tunnels through the ground.
7. how does the earthworm's digestive system take food from the soil it eats: in the intestine, the enzymes released turns the parts in the soil it can eat into a sludge that it can absorb with its bloodstream.
8. what would you find if you dissected past the clitellum: continuous, repeated segments. exactly identical, with intestine and nephridia until the ednd of the worm, where you would find the anus.
9. What did each germ layer form into for the earthworm: Ectoderm: skin and nervous system Mesoderm: septa, muscles, and reproductive organs Endoderm: digestive tract.
10. what is the function of the nephridium, how does it complete its function: the nephridia's job is to take nutrients from liquid sitting in the body cavity absorbed through the worm's pores and to excrete the remaining ammonia. the liquid enters the nephridia from the last segment, it travels through the nephridia and is extracted of all nutrients in it. these nutrients are sent to he bloodstream by blood vessels wrapped all around the nephridia. all remaining liquid still in the nephridia after this process is excreted out an external pore.
11. How is the sandworm similar to the earthworm: Similarities: belong to phylum annelida, triploblastic, anterior cephylization, segmentation, and a closed circulatory system. Differences: classes (earthworm: oligochaeta, sandworm: polychaeta), sandworm is a marine worm, earthworms live on (or in) land. parapoda instead of setae. the sandworm has gills that the earthworm doesn't have.
12. how is a leech designed as an ectoparasite? how is it similar to an earthworm: The leech's anterior sucker and it use of anesthetic and anticoagulant make it suitable as an ectoparasite, as does its 'folding' stomach allowing for extra space for blood. the leech and the earthworm are similar because they belong to the same phylum, both show segmentation, and anterior cephylization.
2. trace the earthworm's digestive tract: the Earthworm eats dirt with it's mouth (once the prostomium opens), the dirt goes through the esophagus and into the crop. here the food sits until the earthworm is ready to digest it. when its ready, the dirt is pushed into the gizzard where its 'ground up' by the muscles around the crop contracting. after being 'ground up' by the gizzard, the dirt is pushed into the intestine, here enzymes break down the parts in the soil that the earthworm eats and absorb the broken down particles. the remaining dirt is pushed through the intestine and out the anus.
3. what parts of the earthworm serve as its brain? what connects the brain to the rest of the body: the nerve collar serves as the earthworm's brain, the ventral nerve cord connects it to the rest of the body.
4. Which of the parts of the earthworms body that you saw are included in the excretory system: we saw the nephridia during the earthworm dissection, these excretory organs are in charge of liquid waste. the fluid inside the previous section is brought to the nephridium and whatever nutrients that are in it are absorbed and sent via the bloodstream to parts of the worm's body. the rest of the liquid is excreted out the side of the worm.
5. how can you find out whether an earthworm eats soil: cut open the worm's digestive tract. (???) or watch a live worm eat dirt.
6. how do the earthworm's setae make it better adapted to its environment: the setae, being tiny little 'legs' help the earthworm move through tiny passages in the ground. because they are so small, they don't get in the way as the worm tunnels through the ground.
7. how does the earthworm's digestive system take food from the soil it eats: in the intestine, the enzymes released turns the parts in the soil it can eat into a sludge that it can absorb with its bloodstream.
8. what would you find if you dissected past the clitellum: continuous, repeated segments. exactly identical, with intestine and nephridia until the ednd of the worm, where you would find the anus.
9. What did each germ layer form into for the earthworm: Ectoderm: skin and nervous system Mesoderm: septa, muscles, and reproductive organs Endoderm: digestive tract.
10. what is the function of the nephridium, how does it complete its function: the nephridia's job is to take nutrients from liquid sitting in the body cavity absorbed through the worm's pores and to excrete the remaining ammonia. the liquid enters the nephridia from the last segment, it travels through the nephridia and is extracted of all nutrients in it. these nutrients are sent to he bloodstream by blood vessels wrapped all around the nephridia. all remaining liquid still in the nephridia after this process is excreted out an external pore.
11. How is the sandworm similar to the earthworm: Similarities: belong to phylum annelida, triploblastic, anterior cephylization, segmentation, and a closed circulatory system. Differences: classes (earthworm: oligochaeta, sandworm: polychaeta), sandworm is a marine worm, earthworms live on (or in) land. parapoda instead of setae. the sandworm has gills that the earthworm doesn't have.
12. how is a leech designed as an ectoparasite? how is it similar to an earthworm: The leech's anterior sucker and it use of anesthetic and anticoagulant make it suitable as an ectoparasite, as does its 'folding' stomach allowing for extra space for blood. the leech and the earthworm are similar because they belong to the same phylum, both show segmentation, and anterior cephylization.