標題: In a study published May 23 in the journal Proceedings of the Royal Academy B 2 [打印本頁] 作者: klggezfs 時間: 2016-3-25 00:06 標題: In a study published May 23 in the journal Proceedings of the Royal Academy B 2
Evolution shapes environment of Connecticut lakes
Yale University researchers found Christian Louboutin Shoes Ebay a prime example of this evolutionary feedback loop in a few lakes in Connecticut, where dams built 300 years ago in Colonial Ghd Straighteners Melbourne times trapped a fish called the alewife.
In a study published May 23 in the journal Proceedings of the Royal Academy B, the Yale team describes how this event fundamentally changed the structure of the alewife and, with it, the water flea that the alewife feeds upon Beats Wireless and the food chain that supports them both. "In this case, we see a cascade of evolution that was propagated throughout the food web within the last three centuries."
And evidence can be seen in relative clarity of the state's lakes during the spring.
Up and down the Atlantic coast, alewife swim to fresh water lakes to spawn every spring before returning to the ocean in the fall. They voraciously feed upon large plankton and the water fleas Daphnia, which are also main consumers of small plankton and algae. In these lakes, there is intense predation by alewives for Daphnia, which reproduce quickly and in huge numbers. These water fleas quickly consume the algae, which leave the waters of Chi Straightener Price these lakes clear in the spring.
However, in lakes created by the dams of Colonial settlers, the water is much less clear in the spring. The Yale study Christian Louboutin Melbourne Store explains why: Since the alewife cannot migrate, it must eat plankton year round, year after year. Evolution favored fish with smaller mouths and a different Christian Louboutin Stores gill structure, which make it easier for them to feed upon small plankton common in lakes. These evolutionary changes in the alewife also caused evolution in Daphnia, which no longer need to reproduce quickly in massive numbers. As a result, these lakes are more cloudy because water fleas eat less algae.
Here, evolutionary interactions between a predator and prey determine the ecology of these lakes, note the researchers.
"Natural selection favored survival of fish with smaller mouths and gills with filters more closely spaced that helped them harvest the smaller plankton," said Matthew R. "This, in turn, drove genetic changes in the Adidas Wings 2.0 Cheap rates of population growth of Daphnia, and these two changes then determine amount of algae present in lakes."
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