Natural History, September 30, 2002

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What does it mean to be a man? Part of the answer depends on where you ask the question. In some places, being a man may include spending Sundays watching football. In others, it may include completion of a rite of passage, such as getting buried up to your chin in an ant nest on your thirteenth birthday. Of course, there’s some biology involved, too, and crucial to that biology is a peculiar chromosome called the Y. Men and women normally carry twenty-three pairs of chromosomes. Each pair consists of two matching chromosomes, with one exception: men normally have one chromosome called X paired with a dramatically smaller one called Y. Women, on the other hand, have two X’s.

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Natural History, June 30, 2002

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Smell, above all other senses, is our link with history. It takes just a sniff of certain odors-the ozone tang of rain falling on blacktop or the crisp sting of frying onions-to instantly hurl us back decades. And our sense of smell has a history of its own, reaching back more than 500 million years. Until recently, however, scientists have had relatively little evidence on which to base a reconstruction of its evolution. They’ve only been able to compare the olfactory senses of living vertebrates or turn up the occasional fossil nose.

Continue reading “The Rise And Fall Of The Nasal Empire” →

Natural History, April 30, 2002

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“The eye to this day gives me a cold shudder,” Charles Darwin once wrote to a friend. If his theory of evolution was everything he thought it was, a complex organ such as the eye could not lie beyond its reach. And no one appreciated the beautiful construction of the eye more than Darwin-from the way the lens was perfectly positioned to focus light onto the retina to the way the iris adjusted the amount of light that could enter the eye. In the Origin of Species, he wrote that the idea of natural selection producing the eye “seems, I freely confess, absurd in the highest possible degree.”

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Science, April 26, 2002

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Charles Darwin spent just over a month on the Galápagos Islands in 1835. The peculiar finches he collected there, each species with a distinctive beak shape, helped inspire his theory of evolution by natural selection. In 1973, Peter and Rosemary Grant, a husband-and-wife team of Princeton University biologists, returned to the Galápagos to observe the evolution of Darwin’s finches up close. On the volcanic island of Daphne Major, they and their students have been keeping track of every single finch from birth to death, allowing them to quantify the effects of natural selection on the birds. The ongoing study is “one of the true classics of evolutionary biology,” says biologist John Burke of Indiana University, Bloomington.

Continue reading “Darwin’s Avian Muses Continue to Evolve” →