Monday, March 15, 2010
Tiktaalik roseae: Transitional species
Tiktaalik lived approximately 375 million years ago (Devonian age) and it is a "missing link", a transitional species. It shows characteristics of fish and tetrapods (four legged animals). This animal had both gills and lungs and also fins and leg like limbs (when fins became limbs). It was discovered in the Canadian Arctic in 2004.
Click here Tiktaalik WebPage Univ of Chicago to see details about how it has evolving characteristics. It also provides a simple explanation of how lucky we are to even find a fossil. There are special circumstances for fossilization and exposure of a fossil. After all life cycles itself and scavengers usually make clean work of any decomposing matter. I live in the country and deer get hit frequently. One day my little Jack Russell terrier brought home a whole deer leg. It was both funny and disgusting. The website has pictures of the dig and the painstaking effort to bring the fossil to "life".
Evolution for all living species is continuous. The term "missing link" is misleading because insinuates that there were unique creatures that provided a link between one species and another as if it only served that purpose. Actually all species are transitional. Humans as we know them today will look quite different one million years from now. In fact there could be multiple branches of future "humans". I prefer the term transitional over missing link and it is even better to talk in terms in transitional features rather than transitional species.
Here are some other links related to this exciting discovery