NEW YORK: Scientists have come to believe that several species of animals are changing genetically to adapt to the phenomenon of global warming. They say smaller animals like squirrels, some of the birds and insects, which are capable of breeding quickly, are showing signs of new behavioral patterns in order to increase their chances of survival.
Most of these genetic adaptations are intended to cope with the changes in climate, like the increase or decrease of seasons.
Larger animals may find it difficult to cope with climate change as they are not capable of adapting genetically to the changes as smaller and more fertile animals, say the scientists.
Citing examples of species like red squirrels in Canada reproducing earlier in the year and German blackcap birds migrating and arriving earlier at their nesting areas, William Bradshaw and Christina Holzapfel, professors at the University of Oregon in Eugene, say studies extending over decades have indicated that rapid climate change have led to "heritable, genetic changes in animal populations."
Their findings are reported in the journal Science.
According to Bradshaw, global warming is happening at a faster rate at more northerly latitudes and this is leading to longer growing seasons, and less cold stress caused by extreme winter weather. "Over the past 40 years, animal species have been extending their range toward the poles and populations have been migrating, developing or reproducing earlier," he said.
These changes have been attributed to "phenotypic plasticity" or the ability of animals to modify their behaviour, morphology or physiology in response to altered environmental conditions, he said.
However, in addition to these ad hoc changes in behaviour, the two scientists also point out to another major evolutionary change that is happening at the level of the genes caused by rapid climate change.
The scientists also say there is little evidence to suggest that these animals are changing genetically to adapt to higher summer temperatures associated with climate change. But, over evolutionary time such changes should appear, following the genetic shifts in the timing of seasonal events, they added.
The article also warns that unless the long term magnitude of rapid climate change is widely acknowledged and effective steps are taken to mitigate its effects, familiar natural communities will cease to exist.
