Tag Archives: Biology

Missing Mutations Suggest a Reason for Sex

For a species whose numbers show no signs of collapsing, humans have a shockingly high mutation rate. Each of us is born with about 70 new genetic errors that our parents did not have. That’s much more than a slime mold, say, or a bacterium. Mutations are likely to decrease an organism’s fitness, and an avalanche like this every generation could be deadly to our species. The fact that we haven’t gone extinct suggests that over the long term, we have some way of taking out our genetic garbage. And a new paper, recently published in Science, provides evidence that the answer may be linked to another fascinating procedure: sex.

For about three decades, one of the senior authors of that paper, Alexey KondrashovRead the rest

Plants turn their tormentors into cannibals

Enlarge (credit: Brian Connolly)

Plants are a lot less passive than their reputation makes them out to be. They foster helpful microbes, have internal systems of communication, and can even share information with their neighboring plants. When they’re being eaten, their alarm signals call in predator species that consume whatever’s eating them.

Now, a new paper suggests that predators aren’t the only danger called in by those alarm signals. Indirectly, the signals induce a starvation-driven cannibalism among the erstwhile herbivores. The result is fewer insect pests and greater plant health.

Fine young cannibals

It turns out that cannibalism is widespread among the insects that otherwise spend their time munching on plants. “It often starts with one caterpillar biting another one in the rear, which then

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How Nature Solves Problems Through Computation

There are many patterns of collective behavior in biology that are easy to see because they occur along the familiar dimensions of space and time. Think of the murmuration of starlings. Or army ants that span gaps on the forest floor by linking their own bodies into bridges. Loose groups of shoaling fish that snap into tight schools when a predator shows up.

Then there are less obvious patterns, like those that the evolutionary biologist Jessica Flack tries to understand. In 2006, her graduate work at Emory University showed how just a few formidable-looking fighters could stabilize an entire group of macaques by intervening in scuffles between weaker monkeys, who would submit with teeth-baring grins rather than risk a fight they thought they would lose. But … Read the rest