Chichlids, Lake Victoria and Evolution
Studies of Lake Victoria in Africa have found astonishing rates of evolution in the chichlids that live there. From one original type of chichlids, many species have now formed.
One group of scientists feel that the lake completely dried out around 12,400 years ago - and therefore that all of the chichlids that now exist there trace back to a common ancestor at that point. Other scientists feel that even at its driest point, there were "pockets" of water that held fish. They feel the common ancestor group traces back to around 100,000 years. In either case, both timescans are incredibly short for the degree of evolution shown here and most scientists feel these chichlids are the fastest example of known evolution within fish and mammals.
Chichlids are a tropical fish type that are known for their tendency to keep their young safe within their mouth. The chichlids in Lake Victoria are great for research because no new fish could "wander in" from other lakes or streams. DNA testing has shown that these fish all descended from a single group of fish.
Where the initial chichlids were all similar, over the centuries they have evolved to adapt to their own areas of the lake. The current species of chichlids in that lake clearly look different from each other. One set of the chichlids eats other fish. Another set of them eat insects. A third set eats algae. And there are many other differences, depending on where in the lake a given group of chichlids chose to settle down.
What Defines a Species?
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