In a comparative analysis across vertebrates of the many cell types in the retina -- mice alone have 130 types -- researchers concluded that most cell types have an ancient evolutionary history. Their ...

The second science -- Simple selection -- The genetic and ecological context of selection -- History, chance, and necessity -- The rate of genetic deterioration -- The rate of environmental ...

The Indigenous peoples of the Bolivian highlands are survivors. For thousands of years they have lived at altitudes of more than two miles, where oxygen is about 35 percent lower than at sea level.