A Snapshot of Pupfish Evolution.

Jan. 10, 2013

 

Summary:

 

As a graduate student, Chris Martin has bred more than 3,000 hybrid fish in his time in subjects of  evolution and ecology at UC Davis.   He made one of the most inclusive snapshots of natural selection and demonstrated an important point in evolutionary biology. "The adaptive landscape is very important for evolutionary biology, but rarely measured," said Martin.  It takes variable traits in an animal or plant, spreads them over a surface, and exposes points of success (what evolutionary scientists call fitness) where those traits become effective, or adaptive.  Martin studied species that he found only in a few lakes on the island of San Salvador in the Bahamas, where some of the fish have evolved in different-shaped jaws which allow them to feed on hard-shelled prey like snails or, in one case, to snatch scales off other fish.  "In a paper published in 2011, Martin showed that these San Salvadoran fish are evolving at an explosively faster rate than other pupfish."  Martin breed those fishes that he found with different types of jaws.  Then he studied and made measurements on the hybrids.  when he was done with his studies, he released those fishes in to the stream of their grandparents.  It was seen that most of the surviving fish were on an isolated peak adapted to a general style of feeding, with fish adapted for eating hard-shelled prey. Competition between the fish had eliminated the fish, in which whose jaws put them in the valleys between those peaks. The scale-eating fish did not survive, and eventually population decreased.  Scientists are still interested in how those ones that couldn't survive can't make it to the peak.  Martin concluded and said "The results explain why most pupfish species in America have pretty much the same diets."  he also said "An early burst of variation, when fish entered a new environment with little competition could have allowed the shell-eaters and scale-eaters to evolve on San Salvador."

 

Connection:

 

This article's concept is what we are learning that some kind of evolution has happened in the past, about millions of years ago.  These unique fish (scale-eating and hard-shell eating) had competition over food.  Eventually, one group of population survived and the other population decreased.  This was an example of natural selection.  Adaptation also played and important role in some fish to survive and reproduce in a particular environment.  Just like Darwin, Martin went to Bahamas instead of Galapagos islands, and studied to fish instead of finches. 

 

References:

 

http://www.sciencedaily.com/releases/2013/01/130110142043.htm

 

by Christopher H. Martin, Peter C. Wainwright.

01/8/2013