The glow of a beetle has inspired an elegant bit of evolutionary detective work that appears in the Proceedings of the National Academy of Sciences. Americans like myself are familiar with fireflies, but in the tropics the night is also illuminated by beetles. When Darwin came to Brazil on the Beagle, he amused himself by noting how the beetles were “rendered more brilliant by irritation.” Naturalists have gotten a bit more sophisticated at studying beetles since then. They now know that the male beetles use the light organs on their underside to get the attention of females that are sitting in the trees and bushes; when the female sees a glow she likes, she registers her approval by flashing light organs on her back. (Fireflies do the same thing, but while they flash, the beetles give off a steady glow.) Scientists also know how the glow is made–a gene creates a protein called luciferase, which cuts up another protein called luciferin, releasing photons at a distinctive frequency. Depending on the species, the frequency is different.
Texas may be off the hook for now, but Razib at Gene Expression observesthat some medical students at the University of Oslo are lobbying for anti-evolution lectures. I guess I’ll try not to be in Norway if I need antibiotics.
For everyone interested in how their brain works, I’d suggest checking out a book coming out soon called Picturing Personhood, by MIT anthropologist Joseph Dumit. Dumit shows how easy it is for brain scans to become cultural Rorschach tests. Scans of mental activity, such as fMRI or PET, are basically complex graphs that represent the relationships of data gathered in very narrowly defined experiments and which are then statistically massaged with special-purpose software. But for most of us non-scientists (and even some scientists) it’s easy to look at these images as objective snapshots of thought. As Dumit points out, it is even easier for us to impose what we want to believe about human nature on those pictures, getting a comforting feeling of certainty from our misconceptions about how neuroimaging really works.
Continue reading “This Is Your Brain On Racism. Or Is That Liberal Guilt? “
Over the past couple years, a few pounds of rock from Australia have been the subject of a fierce scientific battle between geologists and paleontologists. Some paleontologists have claimed that microscopic marks in the 3.5 billion year old rocks are the oldest fossils of life yet found. Some geologists have recently argued that the marks are just odd mineral formations that could have been created without the help of life. Today in Science, the geologists have struck again. A team from Spain and Australia mixed up some silica, carbonate, barium, and other compounds that can be found in the Australian rocks. With a little lab cooking (which they argue is akin to how the rocks formed) they were able to create little lumpy chains. When UCLA’s William Schopf discovered similar little lumpy chains in 1993, he declared that he had found fossils of cyanobacteria (also known as blue-green algae). Not only did the chains look like living chains of cyanobacteria, but Schopf also found organic carbon around them. The geologists who published the Science paper today point out that non-living processes can create “organic” carbon too, and when they added this carbon to their recipe, they found that they could readily coat their pseudofossils as well.
The case of Terri Schiavo has moved back into the Bleak House realm of endless trips to the courthouse. As I mentioned in an earlier post, Schiavo lost consciousness thirteen years ago, and her husband has been trying for the past few years to have her feeding tube removed over the objections of her parents. The Florida legislature recently passed a law that gave Governor Jeb Bush the authority to order Schiavo’s tube put back in, and now her husband is going to court to challenge the constitutionality of the law.