(Apologies for ASR being both late and brief. Can someone please contact Robert Mueller and ask that he walk people in for their pleas earlier in the week?)
Can being very small be as bad as being very large?
This week’s example of scientists arguing very politely through letters isn’t really an argument. But it is about one of my favorite topics — the relationship between size and extinction.
When paleontologists look back through the Great Extinctions, one way they can measure their severity is by looking at a kind of “cut-off size.” In severe circumstances, it’s almost as if the planet holds up a pointer and says “you can’t go forward if you’re taller than this line.” The worse the conditions, the lower the line.
Contrary to how it’s often portrayed, size can be the biggest factor in determining which creatures survive a mass extinction. For example, at the boundary of the Cretaceous and Tertiary, when dinosaurs left the stage, so did 93 percent of the known mammal species. The groups that survived were all quite small. So every mammal alive today, from humans to elephants to blue whales, evolved from an ancestor that, 65 million years ago, was not much larger than a mouse. Oh, and all of them were likely scavengers that survived by chowing down on the dead bulk of the larger critters along with snacking on the insects, which were also eating all those dead dinos.
There was nothing special about events at the end of the Cretaceous that said “lets get those non-avian dinosaurs.” There were just no mouse-sized dinosaurs.
Animals at the top end of the size scale are always in a precarious position. They need the most food. That also means they generally require large ranges of suitable territory. Large animals also can’t burrow underground to shiver through a particularly cold winter. Their sheer size leaves them exposed to conditions and challenges that smaller creatures can avoid. Size has its advantages, both in competing against other animals for similar resources and in the ongoing war with predators, but it has its demands.
That’s why, even without a major extinction event, the largest animals are also among the most fragile as a species. Just a little twist in the conditions that made it possible for them to grow so large — a difference in climate, the introduction of a new species in the area, a change in available resources — and they can be gone.
But recently a group of scientists from the West Coast, including a trio from the University of Oregon, argued that being very small is just about as equally precarious as being very large. The reasons for this are not the same, of course, but very small species have to meet challenges of a different sort — greater predation risks, issues with reproduction, revised feeding strategies — that can require some pretty extreme engineering. A robin may be able to hunker down during a cold, rainy day, but a small hummingbird has to eat every ten to fifteen minutes — or die.
So the West Coast team worked out the numbers across a range of environments and suggest that the elevated extinction risk at the bottom of the size scale is about as great as that at the top.
And in totally-not-opposition, a group of German scientists argues that this information can help explain changes in studies of freshwater environments better than typical studies that focus on medium-large animals that are regarded as important to the food supply. Also that the health of such ecosystems might be better understood by tracking the very small.
Which isn’t science going forward by two groups hurling their ideas in opposition. It’s one group saying “hey! look at this information” and another saying “wow, that really helps explain what we’ve been seeing.” And that’s very cool.
Young pterosaurs needed care — much like young birds
Birds are dinosaurs, the only group of them lucky enough to have the requisite tiny, able to survive on bugs, members around at the critical moment. On the other hand, pterosaurs were not dinosaurs. However, they came from a related group.
Pterosaurs got their flying act together in the Triassic, making them the oldest group of flying vertebrates. They had an incredible range in size, from pigeon-like to holy frickin’ flying giraffe and also a very wide range both in geography and habits. While no one is really missing having T. rex on the planet, a few giant azhdarchids, with wingspans above 40 feet, would be a lovely sight in the evening … so long as they were eating someone else’s cattle. And only cattle.
In any case, a group of Chinese and Brazilian scientists found a group of better than 200 pterosaur eggs, and were able to scan both their internal structure and several fossilized pterosaur embryos. What they found was that young pterosaurs were small, fragile, and almost certainly flightless — much like young birds. Which implies quite a bit about the kind of care they would need and about the behavior of adult pterosaurs.
There’s still a lot that’s difficult to discover from looking at bones and eggs — did both pterosaur parents participate in raising the young? Did they regurgitate food for their young as do many birds? Did young pterosaurs who, based on the Chinese fossils, lived in large groups, have a call or other signal that summoned their specific parents? Short of a Jurassic Park scenario, these answers could be difficult to come by.
However, since only a few years ago we discovered what is potentially the first flightless pterosaur, perhaps somewhere, in some corner of the Cretaceous, there was a warmer, and probably scarier, March of the Penguin … saurs.
Don’t measure the genes, measure the land
If the purpose of a wildlife preserve is to protect biodiversity, how do you tell if it’s working? You could make an effort to capture a representative set of the local biology and send it off for genetic mapping, but that can be both difficult and expensive.
I once took part in an effort to determine everything (above microscopic level) that lived in a single acre of American woodland, and tackling the project took over two dozen biologists on site for months with everything from shovels, to traps, to mist-nets. This particular study also included clipping toes off the left rear feet of voles with a paper-punch to show that they’d been previously caught — yes, we were that thoughtlessly cruel to the short-tailed mouse-like critters that are likely the most common mammal in your area. Even if you’ve never seen one.
But a team from the University of Queensland in Brisbane argues that you don’t have to measure the genes to see how your experiment in saving diversity is working. You only have to measure the habitat.
To protect biodiversity for the long term, nature reserves and other protected areas need to represent a broad range of different genetic types. However, genetic data are expensive and time-consuming to obtain. Here we show that freely available environmental and geographic variables can be used as effective surrogates for genetic data in conservation planning. This means that conservation planners can, with some confidence, design protected area systems to represent intraspecific genetic diversity without investing in expensive programs to obtain and analyze genetic data.
It’s not going to be perfect, of course, but the statistics included present a pretty effective argument that looking at geography can be a pretty effective alternative to measuring biology directly.
Stone Age wine from Georgia.
Don’t start searching caves near Macon or Atlanta. This is the other Georgia.
A large international groupof archaeologists, chemist, and agricultural scientists took a look at a pair of sites in the South Caucasus region and found good evidence for grape-based refreshment going back 8,000 years. In fact, the most common kind of pot in the region seemed to be designed expressly for hauling wine in serious party-at-my-house quantities.
The chemical findings are corroborated by climatic and environmental reconstruction, together with archaeobotanical evidence, including grape pollen, starch, and epidermal remains associated with a jar of similar type and date. The very large-capacity jars, some of the earliest pottery made in the Near East, probably served as combination fermentation, aging, and serving vessels.
It’s not every scientific paper that includes the phrase “social lubricant.”
Going veggie would increase food, but wouldn’t eliminate greenhouse gases.
The relationship between cows and methane is well documented — by anyone who ever lived near a cattle ranch — and with the inefficiency implicit in growing food to feed to animals then eating the animals, it may seem that a animal-focused food system would be a much bigger producer of greenhouse gases. But a pair of scientists modeled the numbers to project what an American agricultural system would be like if everyone was on a nothing-with-eyes diet.
The modeled system without animals increased total food production (23%), altered foods available for domestic consumption, and decreased agricultural US GHGs (28%), but only reduced total US GHG by 2.6 percentage units.
They also indicate that though this animal-free system would be much more subject to lack of some vital nutrients. Which kind of suggests that the fact one of the scientists from a “Department of Animal and Poultry Science” and the other from the “US Dairy Forage Research Center” might have affected how they ran these models.
I wouldn’t go quoting these numbers in future discussions … but hey, you can bet that someone will. Check back in the future to see if this study shows up in the argument of the week section.
Future doctors are less concerned about people than other people.
Yeah, this doesn’t seem so nice. A bi-coastal group of medical researchers wanted to see where America’s medical professionals fall on the scale of Marcus Welby altruism to Gregory House take-this-pill-and-call-me-never approach. And, as they say at the casino, House wins.
Our main finding that future physicians are substantially less altruistic and more efficiency focused than the average American challenges notions of physician altruism, the fundamental feature of medical professionalism, and has potential implications for policy in a host of health care areas.
That may sound like these doctors are only focused on getting results, rather than comforting patients. But nope, it is much, much worse than that. The medical students were more likely to consider other factors, including “their own (financial) self-interest” than people in other professions. That includes lawyers.
And there’s pretty good evidence that we’ve built a system that’s selecting for these qualities.
Furthermore, medical students attending the top-ranked medical schools are less altruistic than those attending lower-ranked schools.
Future doctors are not just being trained to be cold-hearted bastards who place their own interests above those of the patient, they’re being rewarded for that attitude. Boy, it’s a good thing we don’t have a group of jackasses in Congress dismantling the health care system to give a tax break to billionaires, or things could be really bad.
And yes, I know it’s Mr. Hyde. Just go with me.
Using VR to simulate a really gnarly trip, man.
I’m a big enough fan of VR that I not only have a couple of the most recent versions, I have a set of Virtual I/O iGlasses from the 1990s — a device whose screen refresh is slow enough that putting on a game and turning your head is a really good diagnostic for “what have I eaten the last 48 hours.”
One of the things that VR seems to open up is experiences that you could not have in everyday life. It probably won’t surprise you to learn that I’ve collected multiple programs in which I can go walking with dinosaurs, or swimming with mosasaurs, or flying with pterosaurs. Experimenters have set up VR systems that let you see the world through the “eyes” of someone else, including someone of a different gender.
But in this article, a group of UK scientists put a headset on volunteers to simulate the effects of a serious headtrip.
Here we describe such a tool, which we call the Hallucination Machine. It comprises a novel combination of two powerful technologies: deep convolutional neural networks (DCNNs) and panoramic videos of natural scenes, viewed immersively through a head-mounted display (panoramic VR). By doing this, we are able to simulate visual hallucinatory experiences in a biologically plausible and ecologically valid way.
Their purpose in doing this is mainly to study some of the effects of being in an altered state, without all the messy factors introduced by having someone heavily drugged or diseased. It might also be a way for those of us who are scared to death at the thought of reality-altering drugs to get a taste of what licking that smiley sticker might just be life.
We set out to simulate the visual hallucinatory aspects of the psychedelic state using Deep Dream to produce biologically realistic visual hallucinations.
Off to find the download ...
Today in Weird Things You Didn’t Know You Needed
And the tweet many of us have been waiting for …
And the one we didn’t know we were waiting for …
As usual, the image at the top of the article comes from Compound Interest. You can find a larger version that’s easier to read by going to their site.