How did penguins adapt to the marine environment?

A study published this week in Nature Communications reveals new knowledge on the evolution of penguins. The work, carried out by experts from more than 30 institutions around the world, helps to understand how they adapted to the marine environment.

Over time, these animals have developed the set of features morphological, physiological and behavioral characteristics that make them one of the most specialized that exist today and that have allowed them to colonize some of the most extreme environments on Earth.

Penguins originated more than 60 million years ago. Although they are usually associated with the Antarcticalong before the formation of the polar ice caps they had already lost ability to fly and they had developed the ability to dive propelled by their wings.

Previous studies have provided information on the evolution and diversification of these animals, but they have been limited by sampling problems (for example, the number of lineages included) and by not integrating extinct species. Because nearly three-quarters of known penguin species are represented solely by fossils, the samples of extinct animals they are crucial to understand their evolution and adaptation to the environmental context.

Adaptation of penguins to the aquatic environment

The study authors analyzed genomic data of all existing lineages and others recently extinct and have combined them with information obtained from fossils, in order to reconstruct the evolutionary history of penguins.

The research shows that the diversification of these animals was driven by the climatic oscillations global between cold and warm periods. Due to these changes in climate, populations of different species first shrank and then expanded throughout the Southern Ocean.

“The evolutionary rates and environmental temperature are negatively correlated in the case of penguins”explains to Sinc Chengran Zhou, from the Beijing Institute of Genomics (BGI), one of the authors.

“This suggests that species from high latitudes may have faster rates of evolution than those from low latitudes. Polar penguins were probably forced to shelter further north during ice ages, and subsequently recolonized Antarctica during interglacial periods.”Add.

These results suggest that the selective pressures of an extreme polar environment, together with climatic oscillations, promoted the evolution and diversification of high-latitude species and could have favored their adaptation to cold environments.

The keys: thermoregulation, oxygenation, diving…

The researchers examined the evolutionary process of specific genetic sequences among penguin lineages. Thus, they identified a set of genes involved in thermoregulation, oxygenation, diving, vision, diet and body size that could have facilitated adaptation to the aquatic environment. Analyzes suggest that ancestors of the penguins adjusted their color vision and visual sensitivity to better adapt to the blue light of the ocean environment.

These discoveries improve understanding of how penguins have made the transition to the marine environment, successfully colonizing some of the most extreme environments on Earth.

“Penguins have adapted to an ever-changing world for the past 60 million years, even facing climate changes dramatic. Some species from the polar regions, like Adélie penguins for example, have faster evolutionary rates and can colonize diverse and extreme environments, so we can remain optimistic about their future.”Zhou tells Sync.

“However, we must pay close attention to the growing threat of climate change anthropogenic and keep in mind that, although penguins have the ability to adapt to new environmental contexts, there are very few places suitable for them, so the threat of extinction is always present”Zhou concludes.

Font: Iole Ferrara Romeo / SINC Agency

Reference article: https://www.agenciasinc.es/Noticias/Asi-se-adaptaron-los-pingueinos-al-entorno-marino