You may not be familiar with the word tetrapod, but you know one when you see it. All tetrapods are vertebrates — animals with backbones — and most move on land. They also have four limbs — or their ancestors did, as in the case of snakes and whales, for example. Reptiles, birds and amphibians all count as tetrapods, as do mammals. You’re a tetrapod. By studying fossils, scientists know that tetrapods haven’t always roamed Earth. Now, biologists have found evidence that animals were preparing to walk while still living underwater. Visit the new Science News for Kids webs...

The more things change, the more they stay the same, as a Dec. 29 Associated Press report on genetically engineered corn notes. Like déjà vu, this news story on emerging resistance to Bt toxin — a fabulously effective and popular insecticide to protect corn — brings to mind articles I encountered over the weekend while flipping through historic issues of Science News. More than a half-century ago, our magazine chronicled, real time, the emergence of resistance to DDT, the golden child of pest controllers worldwide. Now much the same thing is happening again with Bt, its contemporary agricultural counterpart. Will we never learn?

Years ago, I read (probably in Science News) that viruses can’t survive long outside their hosts. That implied any surface onto which a sneezed-out germ found itself — such as the arm of a chair, kitchen counter or car-door handle — would effectively decontaminate itself within hours to a day. A pair of new flu papers now indicates that although many germs will die within hours, none of us should count on it. Given the right environment, viruses can remain infectious — potentially for many weeks, one of the studies finds.

Courtship behavior in a classic lab insect is driven by the aroma of dinner. (p. 10)

A computerized amoeba might help show the way. (p. 12)