Darwin finches do not tell the whole story of avian evolution



<a rel = "lightbox" href = "https://3c1703fe8d.site.internapcdn.net/newman/gfx/news/2019/darwinsfinch.jpg" title = "This shows the very different shape of the skull in four species of All birds follow the same diet: the aquatic animals, although they adopt a similar diet, they acquire their prey in a very different way and have very different skull shapes.The colored dots of each skull are the three-dimensional markers used to quantify the shape of the skull, and each color represents a subregion of the skull, from top to bottom, the northern gannet (Morus bassanus), White Spoonbill (Platalea leucorodia), the brown pelican (Pelecanus occidentalis), and the penguin Ad (a penguin) (Pygoscelis adeliae). Credit: Dr. Ryan Felice, UCL ">
Darwin finches do not tell the whole story of avian evolution

This shows the very different shape of the skull in four different bird species that have the same diet: aquatic animals. In spite of similar diets, they acquire their prey in very different ways and have very different skull shapes. The colored dots on each skull are the 3D landmarks used to quantify the shape of the skull, and each color represents a different subregion of the skull. From top to bottom, the gannet (Morus bassanus), White Spoonbill (Platalea leucorodia), the brown pelican (Pelecanus occidentalis), and the Adélie penguin (Pygoscelis adeliae). Credit: Dr. Ryan Felice, UCL

The link between bird diet and skull shape is surprisingly low for most species, according to a new study conducted by UCL and the Natural History Museum, rewriting our understanding of how ecosystems influence wildlife. 39; evolution.

Charles Darwin's nineteenth-century observations of Galapagos finches concluded that bird speciation was primarily influenced by the ecosystem; the way a bird feeds and feeds forms its skull shape and causes evolutionary change.

However, a new study by researchers at UCL and NHM, testing a larger number of species than ever, has revealed that on a global scale, sharing ancestors and behavior are more important factors than diet.

The study, published in the journal of the Royal Society Acts B, tested the skull shape of 352 bird species, representing 159 of the existing 195 families, making it the largest study of its kind.

"If we apply Darwin's conclusion to different types of birds that primarily eat fish, pelicans and penguins should have exactly the same shape of head and beak, since they both use their beaks for However, pelicans have a long beak and a large pocket in the throat, while the beaks of penguins are relatively small, "says Dr. Ryan Felice (UCL Biosciences), one of the authors of l & # 39; study.

"Although they eat the same thing, pelicans and penguins acquire their prey in different ways, demonstrating the important role that behavior plays in cranial evolution."

The jaws of the penguins have a series of thorns pointing in the throat, so the food stays inside when they are caught. The pelicans ingeniously catch the fish in their bag, then turn it over to drain the water and swallow the fish immediately.

"It's the story of evolution, not the diet, that has most influenced the shape of the skull.If you come down from an ancestor looking like a duck, you will probably have a duckbill, what Whatever your diet is, skull evolution parameters, determining the range of potential forms that can evolve, "added Dr. Felice.

The researchers also found that birds that eat cereals, such as finches and quails, and those that survive with flower nectar, such as hummingbirds, exhibit the highest rate of cranial evolution. On the other hand, terrestrial carnivores – hawks, hawks, owls and other birds that hunt and eat with their greenhouses – show a very slow rate of head change.

"It's here that natural selection comes into play," said Professor Anjali Goswami, head of research at the Natural History Museum and co-author of the study.

"Birds that eat nectar or seeds will face a lot of competition for resources and have to evolve to survive."

"Our study is focused on the skull, but we hypothesize that other parts of the body could be shaped by food and ecology, such as wings. , greenhouses and stomachs, because it is the parts of their body that are essential for capturing and digesting prey. "

The study used state-of-the-art equipment to build three-dimensional numerical models with high resolution bird skulls. This allowed the researchers to trace many more points on the skull than before, allowing them to take robust and accurate measurements.

"Our next step is to extend this analysis to other animal groups, such as mammals, reptiles and dinosaurs," said Dr. Felice. "Our goal is to understand all the different factors that have shaped the skull's evolution over time."

Mr. Felice's partners were Joseph Tobias (Imperial College London), Alex Pigot (UCL Biosciences) and Professor Anjali Goswami (UCL Biosciences & Natural History Museum).


Explore further:
The beaks of birds did not adapt to the types of food as previously thought, according to a study

More information:
Nutritional niche and evolution of cranial morphology in birds, Acts of the Royal Society B: Biological Sciences (2019). DOI: 10.1098 / rspb.2018.2677

Journal reference:
Acts of the Royal Society B

Provided by:
University College London


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