- Global temperature changes have been a major driver of penguin evolution, a new study suggests.
- The researchers mapped the evolution of penguins and identified the traits that helped them survive.
- modern penguins they have genetic adaptations that allow them to thrive both on land and in water.
About 60 million years ago, penguins evolved from their flying ancestors into the water-loving swimmers and divers we know today. A new genetic analysis reveals how they developed this underwater prowess, offering the most comprehensive description of the tuxedo-clad bird’s evolutionary history to date.
In a new study, published this week in the journal nature communications, a team of international researchers analyzed 27 genomes, or the complete set of genetic information, from all living and recently extinct penguin species. using that genetic data and the existing penguin fossil record, the researchers compared penguin genomes with the genomes of other birds, such as pelicans and albatrosses.
They found that penguins evolved in response to ancient climate changes, making their bodies uniquely specialized for some of the harshest conditions on Earth.
“This paper provides a step change in our understanding of which genes underpin these different adaptations,” said Richard Phillips, a seabird ecologist at the British Antarctic Survey and co-author of the study, in a statement. Press release.
ancient penguins originated in zealand, a submerged landmass off the coast of Australia, about 60 million years ago. Scientists think that from there, they migrated to South America and Antarctica. Around 30 to 40 million years ago, later groups probably hitchhiked on a strong ocean current that flowed around the globe, called the Antarctic Circumpolar Current.
Penguins lost their ability to fly before the formation of the polar ice caps, as getting up from the ground required too much effort for birds that were becoming expert swimmers.
“Although when most people think of penguins, they imagine them among ice floes and being chased by leopard seals, penguins evolved to be aquatic creatures,” Phillips said.
Penguins in the snow in the Falkland Islands, on June 20, 2022.
Benedikt von Imhoff/Image Alliance via Getty Images
The researchers found that global temperature changes have been an important factor in the evolution of penguins and have contributed to the diversification of new species. For example, the expansion of Antarctic glaciers during the middle to late Miocene, a period from about 5.3 to 16 million years ago marked by significant global cooling, coincides with the appearance of modern crown penguins, approximately 14 million years.
According to the researchers, a set of genetic adaptations, including body size, underwater vision, heat regulation and diving ability, allowed these birds to thrive both on land and in water.
For example, some genes shortened the forearm bones, while others shortened the penguins’ feathers, leading them to develop flippers. Other genes helped penguins store white fat, which functions as insulation and a source of energy, helping the birds stay warm in extremely cold environments.
Keepers at London Zoo keep Humboldt penguins cool with frozen fish treats during a heatwave on July 18, 2022.
Images by Yui Mok/PA via Getty Images
How ancient penguins experienced immense climate fluctuations in the past could offer insight into how they are coping with a warming world. The research suggests that modern penguins are not coping well. Due in part to rising temperatures from climate changehalf of all living species of penguins are listed as endangered or vulnerable on the IUCN Red List of Threatened Species.
One of the new study’s findings is that in warmer temperatures, the rate of penguin evolution slowed. Flightless birds may not be able to handle modern climate change, the researchers say, which is happening at a faster rate than the past temperature swings that ancient penguins survived.
“Over 60 million years, these iconic birds have evolved to become highly specialized marine predators and are now well adapted to some of the most extreme environments on Earth.” the study authors wrote in the new article. “However, as their evolutionary history reveals, they now stand as sentinels highlighting the vulnerability of cold-adapted fauna in a rapidly warming world.”