It is true that the phenomenon is associated with catastrophic disasters. Sea level rises, high temperatures, extreme phenomena. But global warming also accelerates evolution. And this does not seem to be as positive as one thinks. It affects the DNA of the species and natural selection. A team of scientists from the University of Liverpool explored this. Their conclusions can be consulted in an article published in Molecular Biology and Evolution.
Global warming is acting as an unexpected catalyst in the evolutionary machinery. It is not a slow and progressive adaptation. It appears to be accelerating due to constant thermal shocks. These biological alterations are not limited to the affected individual: they immediately cross the generational barrier.
Adapting at high speed
The study analyzed specimens of a species of flies, Drosophila melanogaster, caught in regions with opposite climates such as Spain and Finland. Exposure to high temperatures causes changes that persist in direct descendants during various stages of their lineage. The impact of a single heat wave can influence the expression of 23 specific genes. This biological memory was detected even in the fourth generation of flies. which is equivalent to the great-grandchildren of the individuals who suffered the original heat shock. The mechanism responsible for this inheritance is not a DNA mutation, but rather epigenetic processes that activate or deactivate vital functions very quickly.
The populations of Spain, accustomed to more arid environments, present a much more effective response to heat than the Nordic ones. In the south, the descendants managed to accelerate their development to reach maturity before climatic conditions worsened. Species that already coexist with extreme heat have a greater adaptive advantage in the face of climate change.
Evolutionary disorder
But the specimens from Finland showed notable disorganization. Its lack of evolutionary history with extreme temperatures made its adaptation less precise. Global warming accelerates evolution, but creates unbridgeable biological gaps between different populations of the same animal species on the planet.
The speed with which these changes occur represents a direct threat to the stability of global ecosystems. If evolution is artificially accelerated by human action, many species could suffer premature reproductive isolation. Animal species that live longer, as is the case with humans, have a lower capacity to adapt. You have less ability to adapt to new circumstances.
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