The rise and fall of earth's temperatures over millions of years drives evolution by favoring those species that are able to adapt to changing conditions. Normally, this is a gradual change that shapes species over thousands or even millions of generations. By studying the fossil record, we can identify what kinds of plants and animals changed the quickest. Then there are penguins. Comparing living and fossil penguin species on the genetic level, it turns out that penguins have the lowest rate of evolutionary change of all bird types. That may be the price of becoming so well adapted to an extreme environment in Antarctica, but it doesn't bode well for the birds' futures.
The history of penguin evolution tells us that they lost their ability to fly some 60 million years ago, before the polar ice sheets developed, which hints that they may have become trapped in an environment that became hostile, and they had to adapt or die out. Millions of years later, they are specialists, and their lack of ability to change may be deadly as the earth warms at a rapid pace. Read about the latest discoveries in penguin DNA at ScienceAlert. -via Damn Interesting
(Image credit: Ben Tubby)