Humans are late bloomers when compared with other primates—they spend almost twice as long in childhood and adolescence as chimps, gibbons, or macaques do. But why? One widely accepted but hard-to-test theory is that children’s brains consume so much energy that they divert glucose from the rest of the body, slowing growth. Now, a clever study of glucose uptake and…
Everybody knows the shortest distance between two points is a straight line, and now Harvard researchers have evidence that sperm have been taking the familiar axiom to heart. Though competition among individual sperm is usually thought to be intense, with each racing for the chance to fertilize the egg, Harvard scientists say that in some species, sperm form cooperative groups…
It’s not another tall tale: Evolutionary biologists have developed a new understanding of the genetic basis of short stature in humans. Also known as the pygmy phenotype, a study published Monday in the Proceedings of the National Academy of Sciences shows that this trait has evolved several times over the course of human history. “We have found the strongest evidence…
Large flesh-eating dinosaurs evolved into small flying birds, but it did not happen overnight. An international team of scientists on Thursday described an extraordinary evolutionary process that unfolded over a period of 50 million years in which a lineage of carnivorous dinosaurs shrank steadily and acquired numerous traits that led to the first appearance of birds. The researchers, using techniques…
The classic definition of a biological species is the ability to breed within its group, and the inability to breed outside it. For instance, breeding a horse and a donkey may result in a live mule offspring, but mules are nearly always sterile due to genomic incompatibility between the two species. The vast majority of the time, mating across species…
Old World monkeys have undergone a remarkable evolution in facial appearance as a way of avoiding interbreeding with closely related and geographically proximate species, researchers from New York University and the University of Exeter have found. Their research provides the best evidence to date for the role of visual cues as a barrier to breeding across species. “Evolution produces adaptations…