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Scientists have discovered microorganisms living beneath the ocean floor that appear to have not evolved for more than 2 billion years, a finding that may support the theory of evolution.

The researchers examined communities of fossilized, sulfur-cycling bacteria found in two rock deposits in Western Australia. The first deposit, about 1.8 billion years old, contained bacteria that was nearly identical to the second, about 2.3 billion years old.

"That's the evolutionary distance from the earliest trilobites to human beings," said J. William Schopf, a paleontologist at the University of California, Los Angeles, and the lead author.

Schopf and his colleagues then compared the specimens to modern communities of sulfur bacteria found off Chile in 2007. The bacteria were essentially no different, they found.

The lack of evolution stems from the bacteria's unchanging environment, they concluded in the Proceedings of the National Academy of Sciences.

Schopf said, "If the environment doesn't change, then you would predict the organisms wouldn't change, either."

Chickens count just like us

When humans are asked to visualize numbers, they usually put them on a mental number line from left to right. Zero is to the left, one is to the right, and so on. But why?

The best way to see whether something is truly innate? See if other species do it, too.

In a study published in Science, researchers trained three-day-old chicks to look for food behind a little panel with five squares on it. The researchers then swapped this one panel out for two panels, each showing an identical number of squares — either two or eight.

When the panels had two squares, the chicks would go toward the left one 70 percent of the time looking for food. When the panels both had eight squares, their preference flipped: They went to the right 70 percent of the time.

In other words, the chicks went to the left when the panels showed a smaller number than the one they'd been trained with, and headed right if they saw a bigger number.

This is the first study to suggest that humans aren't the only ones who count this way.

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