Your Inner Fish Blog Entry

I was fascinated by the entire Inner Fish program because discovering the links between our distant ancestor species and uncovering more about the human evolutionary history is extremely interesting and gives us a greater understanding of where we came from and why our bodies are shaped the way they are. I think at the beginning of the program I expected an organism like Tiktaalik to be the transitional animal between fish and amphibians: one with strong and flat arms used to kind of shuffle around on land, possessing both gills and lungs, scaled, possessing fins and a fishlike tail, and one that spends most of its time in the water but can also go for periods above water exploring land. I think Tiktaalik is a lot like some modern fish, pikes I believe, that are actually able to do the same thing and climb onto shore and walk around land for a short time. These fish possess both lungs and gills, but their lungs have a very small capacity so therefore they must return to their native water to survive. Though I will never see if this is true or not because evolution takes so long, I think that these types of pike fish could possibly open up another branch of animal evolution.

I think that a transitional animal between reptiles and mammals would look a lot like a crocodile or a lizard with fur. I think that the animal would be partially scaly, but large portions of its body would be covered in fur as most mammals are. The animal would walk on four legs and have short, stubby legs that it must swing from side to side to move forward. Also it would probably be a land based creature, because most mammals do live on land and not in the ocean like dolphins and whales. I believe that the transitional animal would have hardshell eggs, but incubate them internally and then give birth to live young because this is a combination between reptile and mammalian forms of birth. This creature would also produce milk as all mammals do to feed their young. As for the features of the animal, I think it doesn't have a fully articulated neck, but more like a neck that only looks up and down like a crocodile, and have binocular eyes like most mammals, not eyes on each side of its head as some reptiles like the chameleon has. Finally, the animal would have been warm blooded, which is necessary for the internal incubation of eggs as mentioned above. If the animal was cold blooded, the dramatic shifts in temperature could hurt the offspring. Below is a picture of what I think the transitional animal between reptiles and mammals looked like.

The brown areas of the animal represent the fur-covered areas, while the green parts are covered in scales. The animal is very squat and short, and probably moves around in a shuffling run.