How fast can animals evolve

Sometimes the division between the populations is never breached, and reproductive isolation remains intact purely for geographical reasons. It is possible, though, if the populations have been separate for long enough, that even if brought back together and given the opportunity to interbreed they won't, or they won't be successful if they try.

Learn More An Origin of Species. In the process of natural selection, individuals in a population who are well-adapted to a particular set of environmental conditions have an advantage over those who are not so well adapted. These individuals pass their genes and advantageous traits to their offspring, giving the offspring the same advantages. Generation after generation, natural selection acts upon each structure within an organ like the eye, producing incremental improvements in the process.

Each tiny change in a structure is dependent upon changes in all the other structures. In this way, individual parts of a system evolve in unison to be both structurally and functionally compatible. Eventually, over thousands and sometimes millions of years, the small improvements add up -- the simple, systematic process has produced an almost unfathomably complex organ. Recently, scientists have found clues to the evolutionary pasts of some of the most complex organs, helping to clarify how this process works.

The researchers incorporated these expected extinctions in their calculations of lost evolutionary history and asked themselves: Can existing mammals naturally regenerate this lost biodiversity? Using powerful computers, advanced evolutionary simulations and comprehensive data about evolutionary relationships and body sizes of existing and extinct mammals, the researchers were able to quantify how much evolutionary time would be lost from past and potential future extinctions as well as how long recovery would take.

The researchers came up with a best-case scenario of the future, where humans have stopped destroying habitats and eradicating species, reducing extinction rates to the low background levels seen in fossils. However, even with this overly optimistic scenario, it will take mammals million years just to diversify enough to regenerate the branches of the evolutionary tree that they are expected to lose over the next 50 years.

It will take more than 5 million years to regenerate what was lost from giant Ice Age species. The few remaining giants, such as rhinos and elephants, are in danger of being wiped out very rapidly," says Professor Jens-Christian Svenning from Aarhus University, who heads a large research program on megafauna, which includes the study. The research team doesn't have only bad news, however. Their data and methods could be used to quickly identify endangered, evolutionarily distinct species, so that we can prioritise conservation efforts, and focus on avoiding the most serious extinctions.

As Matt Davis says: "It is much easier to save biodiversity now than to re-evolve it later. Journal Proceedings of the National Academy of Sciences. By signing up, you agree to our Privacy Policy. Select free newsletters: The Weekender. Today's Highlights. Christian Science Perspective. White Plymouth Rock chickens. October 27, By Michael D. Regan Staff. You've read of free articles. Subscribe to continue. Mark Sappenfield. Our work isn't possible without your support.

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