December 29, 2010
Over 150 years ago, Charles Darwin published On the Origin of Species, which is considered the footing of evolution biology. His theory on Natural Selection stated that over time an animal’s genetics will adapt to its environment and that will result in the emergence of species. A team of scientists on a different island recently made another discovery when it comes to genetic changes and animals’ environments.
Scientists predict by midcentury, for at least one month each summer, a passage of ice sheet will be available due to rising temperatures around the world. More and more new hybrid species are being discovered in the Arctic due the rapidly depleting Arctic ice according to a paper published in the latest issue of the journal Nature.
A team of researchers from the NOAA’s National Marine Mammal Laboratory in Juneau, University of Massachuetts, and the University of Alaska say that the seasonal loss of an ice sheet which is a natural barrier between species the size of a continent could cause the extinction of rare marine mammals, the loss of many adaptive gene combinations, and interspecies breeding.
Hybrids aren’t just appearing on the roads in the US and around the world, but in the Arctic as well. One example of this is the Grolar Bear, first discovered in the wild by an Australian scientist in 2006. The Grolar Bear is part grizzly and part polar and is white with brown patches of fur. It could be just the tip of the iceberg when it comes to new hybrid species being discovered in the Arctic.
The team believes 22 marine mammals are at risk for hybridization because of melting ice including the Beluga, Narwhal, North Atlantic and North Pacific porpoises, the Bearded, Harbour, Spotted, Ringed Hooded, and Harp seals, the North Atlantic and North Pacific Minke, the Humpback, Killer, Fin, and Sperm whales, and walruses.
Over thousands of years, Arctic marine animals have developed fine-tuned adaptations, through genes which allow them to survive in such extreme environments according to marine mammalogist and first author Brendan Kelly of the National Oceanic and Atmospheric Administration’s marine mammal lab in Juneau, with conservation geneticist Andrew Whiteley of the University of Massachusetts Amherst and evolutionary biologist David Tallmon of the University of Alaska. Their article looks at these genes and what happens when these species mix their gene pools by hybridization through interbreeding.
According to Whiteley, “the picture is complicated and it is hard for biologists to know exactly what to expect because hybridization can have beneficial consequences in the first generation. But in later generations, the process begins to have more negative effects as genomes mix and any genes associated with environment-adapted traits are recombined. Genes related to any trait that once allowed the animal to thrive in a specific habitat can be diluted, leaving the animal less well suited to surviving and reproducing there.”
Interbreeding might not be so bad in some species, but could be devastating for others. Such as interbreeding between the rare North Pacific right whale with less than 200 whales left and Bowhead whales. It is believed that the whale with the smaller population could become extinct.
The team is calling for an immediate study to be completed on the endangered bears, seals, and whales of the region over the next few decades before large portions of the populations are affected by interbreeding.