Prehistoric humans — perhaps Neanderthals or another lost species — occupied what is now California some 130,000 years ago, a team of scientists reported on Wednesday.

The bold and fiercely disputed claim, published in the journal Nature, is based on a study of mastodon bones discovered near San Diego. If the scientists are right, they would significantly alter our understanding of how humans spread around the planet.

The earliest widely accepted evidence of people in the Americas is less than 15,000 years old. Genetic studies strongly support the idea that those people were the ancestors of living Native Americans, arriving in North America from Asia.

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The oldfield mouse doesn’t seem extraordinary. With soulful black eyes and tiny teacup ears, the rodent lives a humdrum life scurrying about meadows and beaches in the Southeast.

But field biologists have long known that when it comes to sex and family life, this mouse is remarkable: Peromyscus polionotus is monogamous — an exception among mammals — and a solicitous parent.

Fathers and mothers will dig burrows together and build elaborate nests when pups are on the way; after they’re born, the father will help tend to the pups, retrieving them when they fall out of the nest, licking them, and huddling to keep them warm.

Continue reading “Why Are Some Mice (and People) Monogamous? A Study Points to Genes” →

For decades, scientists have been trying to figure out what all the carbon dioxide we have been putting into the atmosphere has been doing to plants. It turns out that the best place to find an answer is where no plants can survive: the icy wastes of Antarctica.

As ice forms in Antarctica, it traps air bubbles. For thousands of years, they have preserved samples of the atmosphere. The levels of one chemical in that mix reveal the global growth of plants at any point in that history.

“It’s the whole Earth — it’s every plant,” said J. Elliott Campbell of the University of California, Merced.

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As biological research races forward, ethical quandaries are piling up. In a report published Tuesday in the journal eLife, researchers at Harvard Medical School said it was time to ponder a startling new prospect: synthetic embryos.

In recent years, scientists have moved beyond in vitro fertilization. They are starting to assemble stem cells that can organize themselves into embryolike structures.

Soon, experts predict, they will learn how to engineer these cells into new kinds of tissues and organs. Eventually, they may take on features of a mature human being.

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