Just three articles this month, all of them related to biology in one way or another. The first one concerns what looks like an evolutionary adaptation in humans to living in the tropics. As this article from BBC News explains, scientists have long known that the birth rates of boys and girls vary across the world and that one of the factors that determine this variance is environmental stress. Biologically, males are considered more fragile than females and since having children is a huge investment, it makes sense that in a harsh environment, women tend to give birth to more girls since they would be likelier to survive.

According to research by Dr. Kristen Navara published in Biology Letters, people who live in the tropics produce more girls than boys compared to more temperate regions, even after adjusting for differences in lifestyle and socio-economic status. As Dr. Navara explains, this could simply be because male sperm works in a different way closer to the equator or that miscarriage rates might be affected somehow, but it could also be interpreted to more generally mean that living in the tropics is itself a form of environmental stress on the human organism.

The article is from Livescience.com by way of Yahoo News, and is about the discovery of a colony of microbes in Antartica that have been sealed off from the rest of the world for 1.5 million years. As detailed in Science, this community exists hundreds of feet beneath the ice without light or oxygen and was only discovered when scientists examined a curious geographic feature at the edge of a glacier, a blood-red waterfall that flows sporadically. It turns out that the glacier water held microorganisms that use sulphur compounds to extract iron from the iron in the bedrock, accounting for waterfall’s colour.

There are no immediate realizations of any great significance from this discovery, though the article notes that it may in time yield insights on how life could exist on other worlds, but the idea of a small patch of life on Earth, cut off from all others for over a million and a half years is alone worth a quiet moment of appreciation and reflection.

Finally, the last article from The Economist advances a new way of looking at the greatest of all land animals, the dinosaurs. Scientists have long known that birds are descended from dinosaurs, and ever since Jurassic Park, most people know that as well. Zheng Xiaoting of the Shandong Tianyu Museum of Nature in Pingyi, China however noticed from fossils of a newly discovered dinosaur of the Ornithischia group, of which the Stegosaurus and the Triceratops are also members, structures that resemble feathers.

As the article explains, proto-feathers have been discovered on dinosaurs before, but only from those of the Saurischia group that includes birds. Since the Ornithischia and the Saurischia split from one another some 80 million years before the appearance of the first birds, this suggests that such structures must have been characteristic of all dinosaurs.

Since no one has ever seen a dinosaur and their likenesses are not captured anywhere, artists have relied a great deal on their own imaginations to depict what these beasts looked like. Over the years, as our knowledge of dinosaurs have improved, such portrayals have been continuously revised as artists adjust to new findings about the posture and movement of different dinosaurs. Now it seems that the time is ripe for the greatest revision yet. No longer can dinosaurs be depicted as gigantic scaly lizards, but instead as colourful flightless birds.