One sure way to link environmental changes to evolution would require a time machine. Going backwards and forwards would allow the viewers to see how certain animals adapt to the weather, environment or other different things.
Since there is no such machine – except in the movies – the team of researchers relies on the next best thing: data and experiments. In doing so, the group is the first to link environmental changes and adaptations to a species — a phenomenon known as “speciation,” according to report to Science.
The Importance of Darwin’s Finches
The team turned to a well-studied species – called Darwin’s Finches, named after the famous scientist, Charles Darwinobserved them in the Galapagos Islands.
In a study 25 years ago, Jeffrey Podosa biologist at Amherst University, has shown that changing the lips of Darwin’s monkeys affects the way they sing. He then thought that when these birds started singing a different song, they could attract different mates, which could lead to further evolutionary change. But at that time he had no way to prove that theory.
Some biologists had studied the evolution of birds’ beaks for decades. For example, they found that drought favors birds with thick beaks for sustenance, because those beaks are more efficient at cracking nuts. Long, thin beaks are ideal for hunting insects, which are rare in long dry conditions.
The shape of their lips then affects the songs they sing, which can attract different potential mates.
If their beaks affect the way these birds sing, does that affect the way other species perceive? says Podos. “It’s very difficult to test.”
Read more: Here Are Some of Darwin’s Most Amazing Animals
Understanding Finch Evolution Over Time
The tricky part is figuring out when, exactly, a species changes enough to be considered different. In the case of birds, a single population from the same species may use pollen as its main food source. Those inhabitants, in time, would have short, thick lips, useful for crushing seeds.
Some residents – again, from the same species, can live in the forest and often eat insects. In time, they would develop small, pointed beaks capable of catching insects.
“But then the real question is, are they different?” says Podos. “And when are they different?”
To answer that question, Podos basically simulated a time machine. Going back was relatively easy, because biologists have collected decades of information about the size and shape of the lions’ mouths in relation to the environment in which they live. They also knew the differences in finch songs related to beak size and shape.
Going forward was more difficult. It would require experimental simulation – and that simulation would depend on the song.
“Let’s imagine what would happen if you had one group focus on this drought and you see the mouth change and change in some way, and everything is based on real information.
Read more: How Does Speciation Drive Evolution?
Dryness Conditions Associated with Oral Excess
The researchers knew from previous work that drought conditions produced thicker beaks in the birds, which reduced their numbers. So they recorded many finch songs from many generations, as the beaks thickened and the frequencies of the song dropped.
Then they went back to the first group of ants they were studying and actually had a party listening to the birdsong. The researchers played a succession of songs – each with a lower frequency than the previous one. The first three generations of change did not change the ropes. But after three more, they didn’t listen to the music at all.
Podos said the study was exciting, because it showed how data and experiments support the theory he developed decades earlier. It also represents a concrete example of changing the scientific method to explain the role of evolution.
Podos says: “We can actually collect data, and find that indeed the diversity of the environment or the diversity of organisms in it can affect the origin of species.” “We link adaptation to speciation.”
Read more: Why Is Darwin Island in the Galapagos Off Limits to Visitors?
The article Sources
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Before joining Discover magazine, Paul spent more than 20 years as a science journalist, specializing in US life science policy and global science career issues. He started his career in newspapers, but switched to scientific magazines. His work has appeared in publications including Science News, Science, Nature, and Scientific American.
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