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1. What are the round patches of skin on the side of the iguana’s head? What are their function? How do they relate to sensory organs in other animals and evolutionary development of homologous structures?
2. Did bones evolve from cartilage? How did bones develop?
3. Are tadpoles born with lungs? When and how do lungs develop? Is it related to what happens with the gills? (note: salamanders have tadpole stages too)
5. Brittle stars – What are their natural predators? How can they exist in such large populations without being eaten? Do they have a special type of defense?
6. What do scientists know about the adhesive of the starfish (or other animals with tube
feet that have adhesive)? Are material engineers studying this?
7. When did claws first evolve? What was their original purpose, and how has it changed with other animals?
5.
ReplyDeleteBrittle Stars have many natural predators. Since they are so small and usually exist in large groups, they are easily seen and eaten by slightly larger animals. Some of their natural predators include: triton shells, different fish species, starfish, hermit crabs, and crabs. Brittle stars stay together in very large groups so it is impossible for a predator to eat all of them. They scatter under rocks for protection and if need be they can loose one of their arms if they are attacked. Their vital organs are located in the center of the Brittle Star, so they can regenerate their arms once one is lost. They can emit a green florescent protein that can be flashed at their predators to confuse them. This can give them enough time to hide under an object or move away as they are very active animals.
Source: accessscience.com
- search: Ophiuroidea (article)
David E.
2. Did bones evolve from cartilage? How did bones develop?
ReplyDeleteThe process by which bones are formed is called ossification. It is this process where connective tissues such as cartilage can be turned into bone. More specifically, Hyaline cartilage leads to development of bone. This ossification process where by blood vessels accumulate minerals into the cartilage tissue and “creating” bone, is how one might say bone ‘evolved’ from cartilage. Also note the chart similar to the one we completed in lab 1. The osteostracans seamed to be where the start of skeletal bone ossification which would lead to the origin of teeth as characteristic “H”.
Donoghue, P (2002). Origin and Early Evolution of Vertebrate Skeletonization. Retrieved May 26, 2009, from Palaeobiology and Biodiversity Research Group Web site: http://palaeo.gly.bris.ac.uk/donoghue/PDFs/2002/Donoghue_Sansom_2002.pdf
4. Rat Fish Anatomy….
The anatomy of a rat fish, clearly distinct and confusing as we saw in class, is actually well documented. First off it is apart of the Chimaeridae family. On the bottom side of the fish below the pelvic fins are ‘sharp retracticing clasping organs.’ I would believe this to be what is depicted in the picture posted on the blog. I found interesting that the ratfish has smooth skin and is without scales. Also, though it has nothing to do with anatomy except in the sense that this fish eats its own anatomy! Yes, it is a cannibal! According to Cathleen Bester it is well documented that rat fish feed on their own eggs and other rat fish. (No wonder the creature looks so sickly!) . With regards to the jaw structure of spotted ratfish they have on the strongest bites. However, they fatigue rather quickly when compared to other cartilaginous fishes.
Bester, C Spotted Ratfish. Retrieved May 26, 2009, from Ichthyology at the Florida Museum of Natural History Web site: http://www.flmnh.ufl.edu/fish/Gallery/Descript/spottedratfish/spottedratfish.html
(2008,August,8). Hard prey, soft jaws and the ontogeny of feeding mechanics in the spotted ratfish hydrolagus colliei. Royal Society Interface, 5, from Web site: http://rsif.royalsocietypublishing.org/content/5/25/941.abstract
Dahlia K.