President Obama is expanding the Pacific Remote Islands Marine National Monument today from the wonderful 86,888 square miles President George W. Bush set up in 2009, to about 490,000 square miles. I gotta love anything involving ocean conservation. Thanks, Bush and Obama!
“This is a great moment,” said Greg Stone, chief scientist for Conservation International. “This is some of the last real tropical ocean wilderness left on the planet, so it’s good put some of these kind of reef systems aside. On top of that there are the protections for the open ocean and I’m assuming for the sea floor from mining,” he said.
From the Guardian article: “Tarawa atoll. Photograph: Richard Vogel/AP”
Many of the biggest challenges humanity faces in the next hundred years are biological: dwindling wild lands and disappearing biodiversity, antibiotic-resistant bacteria, and emerging new viruses, but also feeding nine billion people or more a healthy diet in a climate-changed world. As Theodosius Dobzhansky famously remarked—and as this very website’s name proclaims—nothing in biology makes sense except in the light of evolution. So are there evolutionary answers to all these biological challenges? According to a big new review article just released online ahead of print in the journal Science, the answer is emphatically yes.
The long list of authors, led by Scott P. Carroll and including Ford Denison, whose lab is just down the hall from my office at the University of Minnesota, explicitly connect evolutionary principles to global goals for sustainable development. These include the reduction of both “chronic lifestyle” diseases and infectious diseases, establishment of food and water security, clean energy, and maintenance of healthy ecosystems. Carroll and his coauthors divide the applications of evolution to these problems into cases where evolution is the problem, and those where evolution may offer the solution.
Macrobrachium ohione, by Clinton and Charles Robertson, via Flickr.
The Mississippi River that we know today is a creation of the army corps of engineers. Before they got to levying, dredging and damming it into submission, it was a wild and meandering thing that harbored great concentrations of wildlife. One component of that was a massively abundant shrimp with an amazing life cycle:
It turned out that in pre-colonial times the shrimp traveled all the way north into the upper reaches of the Mississippi’s main eastern tributary, the Ohio River, and back again – a 2,000-mile round trip. It was a journey more amazing than similarly epic migrators like salmon. For whereas adult salmon may have an equally long journey to their upstream spawning sites, it is the quarter-inch juvenile shrimp that swim and crawl 1,000 miles upstream against the strong currents of the Mississippi.
What happened to these shrimp? Go read the story to find out.
Environments can vary substantially in habitat quality, local population abundance, or carrying capacity. Under some climate change scenarios, new, higher quality habitats become available along the margin of a species’ range (e.g. higher latitudes or altitudes) (Thomas et al 2001). These new habitats may be able to support larger population sizes. Factors of demography, evolution, and qualities of the abiotic and biotic communities all interact to determine where a species is found and may influence the ability of a species to expand its range. New research is building genetically explicit models in order to understand how the interplay of these different factors influence evolutionary changes,
The authors of a recent study focus on how the interaction of the demographic process of range expansion changes the way that natural selection favors beneficial and deleterious mutations (Peischl et al 2013). Using both computer simulations as well as mathematical approximations, the authors find that at the range margins, individuals carry a substantial load of deleterious mutations.
I, until very recently, believed that there were two types of people in this world – those who accept the theory of evolution and those who do not understand the theory of evolution. In my mind, it was impossible to be presented with the overwhelming evidence for and beautiful simplicity of The Theory and not be convinced. Yet, a small, informal survey of sophomore-ish biology majors here at LSU revealed only 35% responded with “Evolution” to the question: What are your feelings/beliefs about how we, as humans, came to exist on Earth? To be fair, the highest category was “Some mix of evolution, creationism and intelligent design”, which really means only 23% of respondents did not include evolution. These numbers are much better than our national average: Miller et al. (2006) conducted a multinational survey that showed nearly 40% of Americans deem evolution “false”. This makes us second from the bottom (out of 34 countries!) in acceptance of evolution – right below Cyprus and above Turkey.
Small informal survey of undergraduate science majors.
As it turns out, I have overlooked a third type of person: a person who can be exposed to a well-supported argument for an uncontroversial scientific consensus and reject it. These people are a major source of science denial. Rosenau (2012) published an amazing and concise review this week in Trends in Microbiology that discusses science denialism and how it’s more about identity and social groups than scientific facts.
It’s already the third day of concurrent sessions a Evolution 2012, and I’m starting to get science overload. And I still have to present my own science tomorrow! But here are some more cool results I saw Sunday and Monday:
Vera Domingues presented a study of beach mice, which have evolved lighter fur after colonizing the sandy dunes of barrier islands off the Gulf Coast. As in many other animal species, a mutation at the pigment-related locus MC1R explains a lot of the color change; Domingues showed that in the population of barrier island mice, every copy of the mutant, “light color” form of MC1R is descended from the same ancestor, and that DNA sequence near the mutation resembles sequence from the ancestral population on the mainland—which suggests that the original mutant predates the move to the barrier islands.
Richard Lankau showed how garlic mustard, an invasive weed in the United States, uses chemical warfare to out-compete native plants. Garlic mustard secretes chemicals into the soil that suppress the growth of other plants, and alters the environment for beneficial mycorrhizal fungi—and plants grown with competitors produce more chemicals. But native plants can adapt; samples of a native competitor collected from sites invaded by garlic mustard were better able to survive near the invader than plants from non-invaded sites, and were less able to benefit from mycorrhizal fungi in soil that hadn’t been exposed to garlic mustard chemistry.
Some highlights from the first day of concurrent sessions in the Ottawa Convention Centre, on Saturday the 7th:
Mohamed Noor described the importance of chromosomal inversions—literally, chunks of DNA code that have been flipped end-to-end within the chromosome—in reproductive isolation between two species of Drosophila fruit flies. Inversions have the interesting effect of preventing recombination from breaking up groups of genes within the inversion; but some recombination is still possible, if very rare, and it should create predictable patterns of genetic divergence across the inverted region.
Most of the major phenotypic differences between Drosophila pseudoobscura and D. persimilis map to three regions that are inverted in one species relative to the other—Noor presented work from his lab that finds very fine-scale differences in genetic differentiation across the inversions, consistent with predicted variation in recombination. In a much-retweeted line, Noor pointed out that it’s possible to think of species as “groups of alleles in long-term association.” Chromosomal inversions being one way to help maintain those associations, plainly.