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October 26, 2012

Ecological and evolutionary responses to climate change

"That climate acts in main part indirectly by favoring other species, we may clearly see in the prodigious number of plants in our gardens which can perfectly well endure our climate, but which never become naturalized, for they cannot compete with our native plants, nor resist destruction by our native animals." -- Darwin

People sometimes ask whether wild species can evolve fast enough, or migrate fast enough, to keep up with global warming. I've always thought the answer would depend on how their competitors were faring. If the competitors are just as stressed by higher temperatures as they are, both might survive a moderate increase in temperature. But if the competitors are moving in from a warmer region, so they're already adapted to hotter temperatures, the locals may be doomed.

This week's paper, "Eco-evolutionary responses of biodiversity to climate change" modeled evolution, migration, and competition as climate warms. Their analysis predicted that:

"high dispersal did not reduce extinctions, because the shifting ranges of some species hastened the decline of others... no extinctions occurred without competition"
Relative to displacement by better-adapted migrants, evolution was particularly important in the tropics and near the poles. Species in the warmest areas (e.g., in the tropics) aren't threatened by migration of species already adapted to warmer climates.

The evolution of high-temperature tolerance in temperate species is slowed by maladaptive gene flow from cooler climates, balancing adaptive gene flow from warmer climates, so displacement by other species may trump evolution.

Near the poles, however, gene flow only comes from warmer climates, so it's more consistently adaptive in a warming climate. If penguins from the South Pole mated with penguins from South Georgia, they'd introduce cold-adapted genes, slowing evolution to warmer temperatures -- but there aren't any penguins at the South Pole.
Evolution therefore plays a larger role in responses to warming climate in polar than in temperate regions.

Wondering why you can't access the New York Times from China?

" It is unclear how much the prime minister of China... knows about the $2.7 billion in assets that his family has amassed."

October 18, 2012

A new blog, focused on Darwinian Agriculture

I'm not sure a blog titled This Week in Evolution should have as much focus on agriculture as my recent posts. So I'm starting a new blog, Darwinian Agriculture. Updates, corrections, and discussion of my recently published book by that title will be a major focus, but I hope to include other relevant topics as well. This Week in Evolution will continue to cover a wider range of evolutionary topics, though I may neglect it when I don't have time for both blogs.

October 16, 2012

Comment contamination?

Suddenly I have a bunch of comments on older posts, some of which appear to have been intended for another evolution-related blog. For example, they refer to comments by others that aren't on my blog. I use Movable Type. Any suggestions?

Hmmm... they all link to the same Facebook page. Looks like some kind of spambot that uses comments from blogs on related topics. I'll try switching to reCaptcha screening.

October 12, 2012

This week's picks

A High-Coverage Genome Sequence from an Archaic Denisovan Individual
Can we have archaic and eat it, too?

Bacterial Quorum Sensing and Metabolic Incentives to Cooperate
"we show that quorum sensing-controlled expression of such private goods can put a metabolic constraint on social cheating and prevent a tragedy of the commons"

Closing yield gaps through nutrient and water management"

Complex brain and optic lobes in an early Cambrian arthropod"

October 8, 2012

Darwinian Agriculture reviewed in Science

Allison Snow, whose publications have included some of the best work on gene flow from transgenic crops to weeds, has reviewed Darwinian Agriculture in the journal, Science. Like an earlier reviewer, she noted that I can sometimes be repetitive, but the review was very positive overall. That may explain why Amazon's listing suddenly went from "in stock" to "usually ships within 1 to 3 weeks." You can also order from your local bookstore, Barnes & Noble, or directly from Princeton University Press, whose latest mailing offers a discount.

See also the two-part review by Jeremy Cherfas at the Agricultural Biodiversity Weblog. And if, after reading the book, you agree with Professor Snow that "the book is perfect for discussion-based seminar courses", I may be able to help.

October 5, 2012

This week's picks

Insect Herbivores Drive Real-Time Ecological and Evolutionary Change in Plant Populations

The widely used small subunit 18S rDNA molecule greatly underestimates true diversity in biodiversity surveys of the meiofauna

A Silurian armoured aplacophoran and implications for molluscan phylogeny

Hemisphere-scale differences in conifer evolutionary dynamics

October 2, 2012

Carnival of Evolution

This month's edition looks particularly interesting. Maybe after the rush is over...