Scientist Urges Dormant Eggs to Life to Test Evolution:
The scientists exposed the eggs to sunlight and warmth, about what they would expect in the spring, and the eggs hatched. As they grew to maturity in tightly controlled experiments, they changed over the years, particularly in the length of their spines and the size of their helmets.By examining the fossil record, the researchers found that fish that prey on the small animals also changed significantly over the years, at least in terms of abundance.
About 80 years ago, when the predators were all over the place, the Daphnia retrocurva extended the size of its helmet and spines to make itself less appetizing. Later, when the number of predators shrank, the animal reduced the size of those features, thus conserving its energy for other uses.
The researchers had hit pay dirt. The changes in Daphnia retrocurva were precisely what would have been expected as part of the predator-prey interaction.
Furthermore, DNA analysis shows that the changes were passed on genetically from one generation to the next, until they were no longer needed, thus confirming that the researchers had caught evolution in the act.