Tiktaalik roseae: A Fish-Amphibian Intermediate


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If you were a fish and you wanted to escape predators, wouldn't it be great to be able to jump out of the water and lie on land until they went away? Or, as a predator, flop on land and grab dinner! If this was your plan, you would probably stay in shallow water, close to land, so raising your head to look for predators and prey on land would be an advantage, and of course, you would need to be able to breathe air. How about nostrils and eyes on top of you head, like a modern crocodile, to give you the ability to watch what's going on around you without moving much? Someones beaten you to it, a very long time ago - about 375 million years ago. All of these adaptations can be found in the recently discovered Tiktaalik roseae fossils. These fossils represent a link between fully aquatic and fully terrestrial animals. Many of their characteristics are "fishy" - while others are only useful for living on land. Although we don't know for sure how these animals behaved, they have many of adaptations that allow them to live on land and in the water. This specimen is interesting because it demonstrates how evolution occurs in phases, where characteristics for different lifestyles are both present.


Article and brief video presentation:


National Geographic

NSTA's SciLinks for "Fossil Discoveries"