By constructing an evolutionary tree spanning the past 350 million years, scientists have found that the first vertebrates did not have a voice. Subsequently, the ability to make sounds developed in some species for communication in the dark, but it does not seem to have become an evolutionary advantage. The research results are published in the journal Nature Communications.
Scientists from the University of Arizona (USA) and Henan University of Education (PRC) have studied the history of the evolution of acoustic communication in animals over the past 350 million years. They built an evolutionary tree of 1,800 species from the five main groups of vertebrates - birds, fish, reptiles, amphibians, and mammals - and noted on it whether each species used sound to communicate or rely on other means of communication.
Using statistical analytic tools, they tested whether acoustic communication arose independently in different groups or was the result of evolution. It turned out that the common ancestors of vertebrates did not use vocal communication, and this ability appeared between 100 and 200 million years ago, primarily in group animals leading a nocturnal lifestyle.
Animals constantly pass on all sorts of information to each other: from trying to impress a potential partner to warning of danger and scaring off competitors. But in the dark, methods of transmitting signals such as changing color or body movement turned out to be useless, and the inhabitants of the night had to learn to use the voice that arose during the evolution of the respiratory organs.
The authors believe that those species that are now more active in the daytime also retain relics of the nocturnal behavior of their ancestors. An example is the predawn roll call of songbirds.
"We have examples of the preservation of acoustic communication in groups of frogs and mammals, whose activity is around the clock today, although both frogs and mammals were nocturnal inhabitants hundreds of millions of years ago," one of the authors of the study, John Vince, quoted in a press release from the University of Arizona. (John Wiens).
Another conclusion that scientists made during the study is that the ability to make sounds did not give an evolutionary advantage and did not contribute to more active speciation - the emergence of new species - in groups of animals with a voice. And this contradicts the generally accepted point of view among scientists.
“When viewed on a scale of several million years and within specific groups such as frogs and birds, the idea that acoustic coupling leads to speciation works,” Vince says. diversity.
For example, both birds and crocodiles use acoustic communication, but there are many thousands of bird species and only 25 crocodile species. Silent snakes and lizards have more than 10 thousand species, and all species of mammals with a voice - no more than 6 thousand.
Despite the fact that the role of the ability to make sounds as the driving force of species diversification has not been confirmed, the authors note the amazing stability of this evolutionary trait - once it appears in a group, it does not disappear anywhere, becoming the main method of communication and displacing other types of information transfer.