The Nature of Things

Scientific research often turns up unexpected findings. Consider a recent study about how noise pollution impacts forests in the Southwest. Previous studies had shown that the Black-chinned Hummingbird seemed to have a high tolerance for areas with extreme noise pollution, while another bird, the Scrub Jay, was sensitive to noise and avoided noisy areas. Now, Scrub Jays are known to prey on the eggs and young of the hummingbirds; therefore, the conclusion is that the hummingbirds choose to frequent areas which the jays avoid. In other words, the hummers are using noise pollution as a defense against the jays.  The latest study now shows how this dynamic affects forests. Hummingbirds feed on the nectar of flowers and, in so doing, they pollinate the flowers and help to increase their numbers. Scrub Jays feed on pinyon pine cones and, in so doing, they spread seeds of the pines and increase the number of trees. But in areas of excessive noise, the number of flowers are increasing (...

I am always fascinated to read about the ways in which evolution works to create an integrated and interactive ecology. It's especially interesting to read about the defenses which both animals and plants perfect through the mechanism of natural selection over the course of thousands of years. And not just defenses as such, but also the ways that the bodies of animals - or plants - change over time in order to take advantage of the environment in which they live. That's how the giraffe got its long neck or the elephant its trunk. And, of course, it is how humans developed their upright stance and their big brains. But how did zebras get their stripes? And why did zebras get stripes? Well, the obvious answer is that in the tall grasses where they often grazed, the stripes helped to camouflage them and hide them from predators like lions and cheetahs. It turns out though that the stripes also seem to hide them from a much smaller predator. Scientists have recently completed a st...

"Life will find a way." - Dr. Ian Malcolm in Jurassic Park Two stories in the news this week remind us of the power of evolution and the fact that life will fight hard to sustain itself and that, very often, it will "find a way." These stories are all about the ability of species to adapt to new circumstances. First, Science Daily reports that the mosquito that carries yellow fever has developed a resistance to the widely used insect repellent DEET. They have lost the ability to sense the product and so are not repelled by it. Some scientists are now urging restricted use of this and other repellents so that other species of mosquitoes do not become resistant to them. Secondly, a story in The New York Times detailed how "superweeds" are becoming resistant to the ubiquitous weed killer, Roundup. This herbicide is the number one chemical used in fighting weeds by farmers and by many gardeners around the country. It is not really surprising that weeds ...

For years, conventional wisdom among biologists has been that modern humans and the Neanderthal people evolved along separate branches of the hominid tree and that they did not interbreed. Now a set of researchers has presented evidence that this theory of human evolution was all wrong , that in fact there was interbreeding. Their research on the Neanderthal genome, about 60 percent of which has been recovered, indicates that 1 percent to 4 percent of the genome of modern non-Africans was derived from the Neanderthals. This does not necessarily indicate a strong and consistent blending of the two strains, but it seems certain that there was some at least intermittent intermingling, even though the Neanderthal influence does not seem to have played a significant role in the evolution of modern humans. Back in the 1980s, writer Jean Auel had something of a literary sensation with her "Earth's Children" series of books. The first book, The Clan of the Cave Bear , introdu...

Olivia Judson has a great piece in The New York Times today about the sex lives of plants. Plants, just like the rest of us, have, over millions of years, worked out strategies of sex and reproduction that successfully perpetuate their kind, but, as Judson points out, the plants' sex lives come with some unique obstacles. The most obvious obstacle is that the plant can't move around to find another of its kind to hook up with and so it has to depend on intermediaries. Flowers are the plants' vehicle for delivering their sperm and egg cells to the appropriate recipients and they essentially have two ways of getting those precious bits of matter to combine and make a new plant. One of their allies in reproduction is the wind. It is a bit quirky and unpredictable it is true, but about ten percent of flowering plants do use the wind to spread their pollen. Since the wind goes its own way and is a bit unreliable, wind-pollinated plants tend to produce huge quantities of pol...