http://ift.tt/1NSbGRV
"Bears sharing both species’ DNA have been recorded several times over the past decade. So why are these two species linking up?
It’s called flexible mate choice: The bears are mating with the best possible partners as opposed to not mating at all, and they’re mating because they share relatively close territories and the same branches of the same evolutionary tree.
Intraspecies mixing between the two happened thousands of years ago, thanks to the advance and retreat of glaciers, and of late, it has been boosted by climate change. Scientists say it’s also probably been assisted by policies that protect both bears from culling and hunting, affording further opportunities for mingling." all well and good until this part
"Amstrup has studied bears in the Arctic since the 1970s and was instrumental in helping list the polar bear as a threatened species in 2008. He, like other experts, characterizes this “new” bear relationship as more beneficial to grizzlies than polar bears. That’s because there are more grizzlies than polar bears and because grizzly territory is expanding while polar bear territory is contracting. What that adds up to is a good chance grizzlies could essentially dilute the polar bear population until it doesn’t exist at all, they say."
Replace polar bears with whites and you have a storm front message board...
So how do we justify such talk for human but not other animals they ask.
"Bears sharing both species’ DNA have been recorded several times over the past decade. So why are these two species linking up?
It’s called flexible mate choice: The bears are mating with the best possible partners as opposed to not mating at all, and they’re mating because they share relatively close territories and the same branches of the same evolutionary tree.
Intraspecies mixing between the two happened thousands of years ago, thanks to the advance and retreat of glaciers, and of late, it has been boosted by climate change. Scientists say it’s also probably been assisted by policies that protect both bears from culling and hunting, affording further opportunities for mingling." all well and good until this part
"Amstrup has studied bears in the Arctic since the 1970s and was instrumental in helping list the polar bear as a threatened species in 2008. He, like other experts, characterizes this “new” bear relationship as more beneficial to grizzlies than polar bears. That’s because there are more grizzlies than polar bears and because grizzly territory is expanding while polar bear territory is contracting. What that adds up to is a good chance grizzlies could essentially dilute the polar bear population until it doesn’t exist at all, they say."
Replace polar bears with whites and you have a storm front message board...
So how do we justify such talk for human but not other animals they ask.
via International Skeptics Forum http://ift.tt/1VlLZuo
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