In the last 40 years, Arctic temperatures have risen at over double the pace as for the whole planet.
As a result, numerous species of whales, walruses, fish, bears and seals are beginning to migrate into new habitats.
In these new habitats, they encounter similar species that have not co-existed for thousands of years and interbreeding occurs, reports Nautilus.
One trend scientists have observed is that grizzly bears are moving into the polar bear’s habitat. In 2006, scientists found a cross between a polar bear and a grizzly bear.
In 2010, a second cross was found. Through analyzing its DNA, scientists found that its mother was also a cross between the two species. So, it is unclear how often these crosses are occurring.
It is also unclear how mixing the genes that have evolved over thousands of years of natural selection will impact their ability to survive.
When early modern humans migrated out of Africa thousands of years ago, they met with Neanderthals.
These two groups interbred according to an analysis and comparison of Neanderthal DNA.
Modern human DNA is composed of 2 percent Neanderthal DNA, reports USA Today.
Further analysis of the acquired DNA reveals the genes are related to hair and skin cells. These genes are beneficial for adapting to colder climates.
The analysis also revealed many of the hybrid males were sterile. This could be why a new hybrid species did not evolve.
Instead, Neanderthals became extinct and modern humans dominated the planet.
Hybrids that mate with each other form a hybrid swarm. So, the original species disappear.
“Basically you’ve swapped out the genome that has been fine-tuned by evolution for thousands of generations,” said Andrew Whiteley, an evolutionary biologist at the University of Massachusetts, Amherst.
“We’re speeding up the evolutionary clock,” said Brendan Kelly, a polar ecologist at the National Science Foundation. “If you change an environment rapidly, that’s very few generations, and very little opportunity for an adaptive response.”
“Those changes are very concerning to us,” said Pete Souza, an ecological services manager with the U.S. Fish and Wildlife Service.
Source | http://www.designntrend.com