Jan 11, 2013

Our Fishy Family Tree?

Human beings and all other four-legged land animals are believed to have descended from ocean creatures that lived mil lions of years ago. Some biologists believe that these ancestors are strange, primitive fish called coelacanth (pronounced see-luh-kanth). They have six fins. Four move as pairs, as if they were primitive legs. 

Coelacanths existed as long as 370 million years ago, and it was long believed that they were extinct. But in 1938 a fisherman netted one in the Indian Ocean. Over the years more of these rare fish were captured and studied. The German biologists analyzed blood proteins from live coelacanths. They found that these proteins are like the blood proteins of frogs- the earliest land animals. Scientists consider the structure of proteins to be an important clue to relationships among animals: the more alike the proteins, the closer the kinship. Despite the new evidence linking coelacanths and amphibians, many more studies must be done to determine if coelacanths really are our water-dwelling ancestors. (Adapted from Grolier Book of Knowledge Encyclopedia)