Today Gregor Mendel is a towering hero of biology, and yet during his own lifetime his ideas about heredity were greeted with deafening silence. In hindsight, it’s easy to blame his obscurity on his peers, and to say that they were simply unable to grasp his discoveries. But that’s not entirely true. Mendel got his ideas about heredity by experimenting on pea plants. If he crossed a plant with wrinkled peas with one with smooth peas, for example, the next generation produced only smooth peas. But when Mendel bred the hybrids, some of the following generation produced wrinkled peas again. Mendel argued that each parent must pass down factors to its offspring which didn’t merge with the factors from the other parent. For some reason, a plant only produced wrinkled peas if it inherited two wrinkle-factors.

Continue reading “Move Over, Mendel (But Don’t Move Too Far)” →

Panda’s Thumb has an update on the ongoing drama over teaching creationism in public schools taking place in York, Pennsylvania. Last year a group of residents donated 58 copies of a creationist book called Of Pandas and People to the local school. The board of education reviewed them and gave them the green light. The books are now available in the school library.

Continue reading “Who Gets On the Shelf?” →

Readers were busy this weekend, posting over fifty comments to my last post about HIV. Much of the discussion was sparked by the comments of a young-Earth creationist who claims that the evolutionary tree I presented was merely an example of microevolution, which–apparently–creationists have no trouble with. This claim, which has been around for a long time, holds that God created different “kinds” of plants and animals (and viruses, I guess), and since then these kinds have undergone minor changes, but have never become another “kind.”

Continue reading “Tree Climbing” →

You may have heard last month’s news about an aggressive form of HIV that had public health officials in New York scared out of their professional gourds. They isolated the virus from a single man, and reported that it was resistant to anti-HIV drugs and drove its victim into full-blown AIDS in a manner of months, rather than the normal period of a few years. Skeptics wondered whether all the hoopla was necessary or useful. The virus might not turn out to be all that unusual, some said; perhaps the man’s immune system had some peculiar twist that gave the course of his disease such a devastating arc. But everyone did agree that the final judgment would have to wait until the scientists started publishing their research.

Continue reading “Evolution at Work (and Creationism Nowhere in Sight)” →

I can’t remember the first time I saw the dinosaur fossils at the American Museum of Natural History, but they’ve been good friends for over thirty years. We’ve all changed a lot over that time. I’ve grown up and gotten a bit gray, while they’ve hiked up their tails, gotten a spring in their step, and even sprouted feathers.

Continue reading “Growing Up With Dinosaurs” →