Comparative Anatomy Unit:
In this unit, we studied the different external and internal anatomy of several different animals. We chose an animal to dissect and research for our mini project. I chose to dissect and research a stingray. We started this unit by learning about the different taxonomic classifications of organisms. We also researched the external and internal anatomy of the animal we were going to dissect. We researched the animals ecosystem and food web as well as life stages. Before my dissection, I had to observe two different dissections of different animals.
Observed Dissections:
I decided to observe dissections of a lizard and squid. It was interesting to see and compare the anatomy of two completely different types of animals, one aquatic, and one land.
The squid had an interesting layout of organs. The inc sac, 3 hearts, and liver were all towards the middle surrounded by a set of gills.
The lizard had a straightforward anatomy of intestines, liver, and heart all in the usual places you would expect them to be on a land creature. Below you can find both videos of the observed dissections!
The squid had an interesting layout of organs. The inc sac, 3 hearts, and liver were all towards the middle surrounded by a set of gills.
The lizard had a straightforward anatomy of intestines, liver, and heart all in the usual places you would expect them to be on a land creature. Below you can find both videos of the observed dissections!
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My Dissection: Stingray (Myliobatoidei)
External- The external anatomy of the stingray consisted of hard material to protect the cranial area of the animal. Up above lied the eyes, Snout, Spiracle, and the Fins. The bottom area contained the Nostrils, Gills, Pelvic Fin, Mouth, and the Cloaca. The Spiracle was the nostril on top of the animal that is used to suck in water through the top. The Pelvic Fin was a fin underneath the tail of the animal to help it stabilize while swimming near the bottom of the water. The Cloaca is the reproductive organ of the Stingray. Cutting through the Stingray was pretty challenging as tough cartilage protected its inner organs. Once I broke through its skin, peeling it away was hardly a challenge. I used my pins to keep the peeled skin in place while I removed the organs inside. This didn't mean removing the skin was easy, it was pretty tough to get a clean incision but I made it work.
Internal- Inside the stingray, there were some usual organs you'd expect, as well as organs that I didn't expect to see. It had the usual Gall Bladder, Liver, Intestines, Stomach, Heart, and Kidney. But there were some other parts I've never seen before. What I thought were the Ribs turned out to be its gills. This took me by surprise because at first, I thought that the Stingray had a thick layer of bone protecting it. The main bone mass, however, is located in its fins, and down its tail. It is not a hard Skeletal System as it was easy to cut through and see the bones inside. However the Gills looked very similar to the Ribs you would see on any normal animal, but it was softer. It had a spongy texture that I think helps absorb water into its whole system, making it easy to breathe like a normal fish. Its Cloaca was connected to its Uterus as well as its Rectal Gland. Its Kidney had the shape and look of a human spine. The intestines were easy to remove once I got into the animal, as well as its Gills and Heart. It took some force to get it open. However, once I finally did the organs were removed and paced beside professionally.
Below you can view the video of my own dissection...
Internal- Inside the stingray, there were some usual organs you'd expect, as well as organs that I didn't expect to see. It had the usual Gall Bladder, Liver, Intestines, Stomach, Heart, and Kidney. But there were some other parts I've never seen before. What I thought were the Ribs turned out to be its gills. This took me by surprise because at first, I thought that the Stingray had a thick layer of bone protecting it. The main bone mass, however, is located in its fins, and down its tail. It is not a hard Skeletal System as it was easy to cut through and see the bones inside. However the Gills looked very similar to the Ribs you would see on any normal animal, but it was softer. It had a spongy texture that I think helps absorb water into its whole system, making it easy to breathe like a normal fish. Its Cloaca was connected to its Uterus as well as its Rectal Gland. Its Kidney had the shape and look of a human spine. The intestines were easy to remove once I got into the animal, as well as its Gills and Heart. It took some force to get it open. However, once I finally did the organs were removed and paced beside professionally.
Below you can view the video of my own dissection...