Turu, the blue heron that usually patrols outside my window, has deserted me this week. There is the little factor of the lake being completely frozen so that he can’t reach the fish, but still … I miss him.
Since it’s the National Day of Feathered Dinosaurs, I’m reaching back a couple of years for this article which provides a great example of parallel evolution.
Few surprises are more compelling than the recent discovery that falcons are more closely related to parrots than they are to hawks and eagles. ...
When biologists sat down to organize bird biodiversity, most put the falcons in the same taxonomic basket as hawks and eagles. It turns out this was a mistake akin to putting puffins and penguins together. Hawks and eagles are aerial predators, and so are falcons. Apparently, the predatory lifestyle has driven these two unrelated groups of birds to converge upon each other — not only in the shapes and sizes of their bodies, not only in the color of their feathers, but also in their relatively sparse numbers and solitary lifestyles.
As it turns out, falcons had ancestors who were likely more colorful, less predatory, and more social — because they’re not sleek relatives of hawks and eagles, they’re parrots in disguise. The demands of specific biological niches often drive this sort of convergence, not just across animals of the same family, like puffins and penguins, but among groups as divergent as dolphins and ichthyosaurs.
None of this means you can get a prairie falcon to beg for crackers. But just as birds are a group of dinosaurs that survived the end of the Cretaceous, falcons might be looked on as a group of parrots that have managed to extend their range far beyond the latitudes and environments where most of their relatives thrive. Which, for the parrot-family as a whole, is a nice bit of flexibility.
Come on in. Let’s look at the week in science.
Genetic diversity helps predict how well species can deal with climate change
Since it’s bird day, here’s a study that focused on how the genetic diversity within a species of warblers helps demonstrate its relative susceptibility to climate change.
Despite evidence that evolutionary adaptation could mitigate climate change impacts, evolution is rarely integrated into predictive models. Integrating population genomics and environmental data, we identified genomic variation associated with climate across the breeding range of the migratory songbird, yellow warbler (Setophaga petechia).
In general, the greater the genetic diversity within a species, the more flexible it is in dealing with habitat loss, climate change, or other sources of stress. Tight genetic profiles bring you to the problem faced by many domestic crops — a narrow range of acceptable conditions and near universal susceptibility to disease. It’s a problem that’s being faced right now among commercially grown bananas which, as I neatly predicted in The Evolution of Everything, is currently facing a crisis that has growers scrambling. This prediction required not even, like, a really smart brain, as bananas faced a near identical crisis only a few decades ago. The reasons? Commercial bananas are all almost all clones of a single plant, giving them the smallest possible range of diversity. Plus, growers never seem to learn.
Getting back to the birds, Yellow Warblers are already taking a big hit from climate change and habitat loss, as are a lot of songbirds. But adding genetic profiles to the models seems like a logic step in predicting what kind of species loss we’re going to face in the near future.
The diverse diet of pterosaurs
And now on the parallel evolution front, a UK researcher has looked at scratches on the teeth of pterosaur fossils in a search for clues about exactly what they ate.
They used infinite-focus microscopes to create 3D images of tooth wear. They then used statistical methods to look at wear patterns in pterosaurs alongside the teeth of living species of bats, lizards and crocodilians that are known to eat insects or fish and other vertebrates. “We use that as our proxy data set to project the microwear of extinct organisms,” says Bestwick.
The shape, number, and positioning of pterosaur teeth has led paleontologists to assign a large number of roles from fish eaters to insect specialists. But this new study is the first to look at how tooth wear in modern animals maps to that seen in among the winged reptiles. Results seem to show that the predictions based on tooth-design were often accurate.
Analysis of the pterosaur Rhamphorhynchus, first found in Germany in 1825, reveals wear patterns that are statistically similar to those seen in modern relatives of crocodiles called gharials, suggesting that Rhamphorhynchus also ate fish. This helps back up a long-standing hypothesis about the ancient reptile’s diet, Bestwick says. Wear patterns on the teeth of Pterodactylus, the first pterosaur ever described, in 1784, suggests it was an omnivore as some experts had also hypothesized, he adds.
Which is good, because very similar analysis is used in speculating about the diet of many other fossil animals, not just pterosaurs. But the predictions weren’t perfect. For example, Dimorphodon has a head with a shape similar to that of a puffin, so fish-eating had been assumed. But results of looking at tooth wear indicate that Dimorphodon was snacking more on bugs and small land vertebrates.
I love this study, because it’s not based on the discovery of some one in a billion fossil, or the application of some new billion dollar instrument. It simply took looking more closely at items that were already on hand.
Timing a murder with microbes
Anyone with an interest in mystery fiction has probably run into some clever literally sleuth who can determine the time of death based on the delightfully disgusting lifecycle of some corpse-feeding fly. But for those who want their timelines based on something smaller and less maggoty, Colorado scientists are looking for a microbe death-clock. And they have their own “body farm.”
On a small hill outside of Grand Junction, CO, the sun beats on dry earth, and human bodies lie face up amid low sagebrush. Inside each corpse, on it, and beneath it, a rich ecosystem of bacteria, nematodes, and other microbes flourishes. As these tiny forces of nature—constituents of the postmortem microbiome—steadily decompose the remains, scientists document their every move.
The results seem to indicate that looking at tiny biomes, with the addition of faster, cheaper DNA sequencing to help nail down the contents, could give a more precise, and more accurate, time than looking at things that are wiggly.
Women are less likely to be invited to speak at universities
Here’s another study that didn’t require anything more than the sense to ask the question and the time to sort publicly-available data. And the results are sadly what you might expect — women are less likely to be brought in as university speakers.
Colloquium talks at prestigious universities both create and reflect academic researchers’ reputations. Gender disparities in colloquium talks can arise through a variety of mechanisms. The current study examines gender differences in colloquium speakers at 50 prestigious US colleges and universities in 2013–2014. Using archival data, we analyzed 3,652 talks in six academic disciplines. Men were more likely than women to be colloquium speakers even after controlling for the gender and rank of the available speakers.
They also determined that women were no more likely to turn down requests. They simply get fewer requests. In academic circles, that’s yet another horrible example of a mechanism that keeps women from advancing.
Measuring your diet in species
Sure, you’ve probably counted calories at some point in your life. And, depending on which “expert” was last on your screen, you may have cut back on carbs, restricted red meats, searched out ‘good fats,’ or all of the above.
But a large international team (that includes a good number of scientists from Belgium and Italy, so you know they were eating well) the best way to measure your diet may be one you haven’t thought of before: How many species are you eating?
Biodiversity is key for human and environmental health. Available dietary and ecological indicators are not designed to assess the intricate relationship between food biodiversity and diet quality.
The 6,226 participants in their study chowed down on 234 species of plants and animals. Those who ate more broadly across the spectrum of living things were rewarded with a better quality of diet when measured broadly against a set of vitamins, minerals, and other micro-nutrients. In fact, every species added to a diet helped fill in nutritional gaps.
However, despite a study that visited many countries and worked across age and income spectra, just nine species accounted for 61 percent of calories consumed. In the United States that’s probably corn, corn, and seven more corns.
One thing about this study: If it was taken to heart, it could really help to make food labeling more interesting.
Good gut bacteria may help immunotherapy fight against cancer
A large international team took a look at the relationship between how patients respond to immunotherapy and gut bacterial. The result confirms a known connection—taking antibiotics can interfere with a good response to immunotherapy—and maps that to potential helpers in the gut.
Matson et al. and Gopalakrishnan et al. studied melanoma patients receiving PD-1 blockade and found a greater abundance of “good” bacteria in the guts of responding patients. Nonresponders had an imbalance in gut flora composition, which correlated with impaired immune cell activity. Thus, maintaining healthy gut flora could help patients combat cancer.
Except … I’m not quite so sure that the arrow in this case is as clear as the study may indicate. There seems to be quite a few steps between saying that patients who have good gut bacteria tend to respond better to immunotherapy and adding the word “because” to that sentence.
Calculating heat waves in a warming world
While everyone (in the part of North America that happens to play host to most television networks) is shivering, University of Chicago scientists have a new, simplified method to calculate the frequency and extent of extreme heat waves … and it works for cold waves, as well.
Here we propose such an algorithm, specifically designed for extreme heat or cold waves, based on statistical physics. This approach gives an improvement of more than two orders of magnitude in the sampling efficiency. We describe the dynamics of events that would not be observed otherwise. We show that European extreme heat waves are related to a global teleconnection pattern involving North America and Asia. This tool opens up a wide range of possible studies to quantitatively assess the impact of climate change.
It would be interesting to know what their equation predicted over the last two weeks.