An Evolutionary ‘Big Bang’ Explains Why Snakes Come in So Many Strange Varieties

An evolving “big bang” explains why snakes come in so many strange varieties

By Jack Tamesiea Edited by Andrea Thompson

When they evolved for the first time from lizards over 100 million years ago, snakes were ecological players who slipped around the fringes of the ecosystems dominated by dinosaurs. But today, there are about 4,000 species of snakes, ranging from the green anacondas that weigh more than adult gorillas with lighter thread snakes than a trombone. These are some of the most effective and diverse predators on the earth. “Snakes are really exceptional,” explains Daniel Rabosky, biologist of evolution at the University of Michigan.

Out of about 25 groups of lizards that have lost their legs independently, snakes have become the only ones to really explode in diversity. A new study published this week in Science Explain why: genomic data revealed that snakes experienced an adaptation burst about 125 million years ago – in their evolutionary history – which helped them to exploit several ecological shortcomings. “The document shows that snakes are an evolutionary” singularity “that has changed the face of the earth,” explains Michael Lee, an evolving biologist at Flinders University in Australia, who studies the evolution of reptiles but has not been involved in the new research.

To determine what distinguishes snakes from groups of lizards without legs, Rabosky and a team of researchers have built an in -depth evolutionary tree. They have shaped its branches using genomic data of more than 1,000 squamate species (the order of reptiles which includes snakes and lizards) to trace the way these scaly critics have changed over time. Finally, they have strengthened this data set with food information of nearly 70,000 individual lizards and snakes, mainly specimens kept in alcohol in museum collections.

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The results showed an early adaptation burst which was apparently linked to the development of specialized features. These features include chemooreceptive structures that help snakes to determine their prey in a expert smell and heat and flexible jaws that help them swallow oversized meals. Some snakes have evolved deadly venom to chase larger prey.

The new paper does not come out on a member to identify which specific trait has led to the success of snakes. Lee says it was probably an interaction of lines that helped them hit the scalable jackpot. “Snakes succeed due to a synergy of multiple adaptations [such as] elongated body, constriction, venom, flexible skulls, “says Lee.” Many legless lizards have one or two of these snake characteristics but have not been so successful. “He quotes a group of geckos who have an elongated body and a flexible skull but have never diversified in addition to a handful of species.

Rabosky is suitable that the adoption of a series of specialized features probably helped to overeat the evolution of snakes. Based on the evolutionary tree of the study, snakes seem to have evolved up to about three times faster than lizards. “The rhythm to which snakes evolve new features and evolve new types of regimes has been essentially implemented in the supply,” explains Rabosky. “The lizards are made a moped while the snakes are on a high -speed train.”

Such a rapid development has probably allowed snakes to exploit more ecological gaps than lizards after the cataclysmic mass extinction which occurred 66 million years ago contained several groups of reptiles, including non -avian dinosaurs. This versatility is still reflected in the diet of snakes today. Most living lizards stick to insects or other small arthropods; Snakes are generally much more adventurous and will tackle animals ranging from rodents and birds to kangaroos and crocodilians.

Although snakes have collectively evolved various tastes, many species are strongly specialized in targeting specific prey. These include species of Pelleter nose snakes, which have evolved to unearth prey, and species of sea snakes, which swim with a gay tail and a snack on prey like reef fish. Other species swallow whole bird eggs. Some even consume harmful dishes that few other species would dare to eat. Most lizards specialize much less and simply eat all invertebrates are small enough to adapt to their mouths.

Rabosky and its co-authors describe the bursting of evolutionary innovation which launched the evolution of snakes as a “macroevolutionary singularity”. As an evolving big bang, these rare events occur when a group of organizations quickly diversify in a variety of new species in the blink of an eye, according to geological standards. The sudden explosion of the diversity of flower plants during the Cretaceous period is another example of this phenomenon, which Charles Darwin called an “abominable mystery”.

This is only one more example, says Rabosky, of the way in which “these big bangs of evolution are deeply important for the history of life on earth”.