These mitochondria, in red, are from the heart muscle cell of a rat. Mitochondria have been described as "the powerhouses of the cell" because they generate most of a cell's supply of chemical energy. But at least one type of complex cell doesn't need 'em, it turns out. Science Source hide caption

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Chris Nickels for NPR
How Sound Shaped The Evolution Of Your Brain
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Male treehoppers make their abdomens thrum like tuning forks to transmit very particular vibrating signals that travel down their legs and along leaf stems to other bugs — male and female. Courtesy of Robert Oelman hide caption

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Good Vibrations Key To Insect Communication
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An illustration of Pappochelys, based on its 240-million-year-old fossilized remains. This ancestor to today's turtle was about 8 inches long. Rainer Schoch/Nature hide caption

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How The Turtle Got Its Shell
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The most recent common ancestor of all today's snakes likely lived 120 million years ago. Scientists believe it used needle-like hooked teeth to grab rodent-like creatures that it then swallowed whole. Julius Csotonyi/BMC Evolutionary Biology hide caption

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Earth's First Snake Likely Evolved On Land, Not In Water
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The size of the brain of a chimpanzee (right) is considerably smaller than that of a human brain. Probably multiple stretches of DNA help determine that, geneticists say. Science Photo Library/Corbis hide caption

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Just A Bit Of DNA Helps Explain Humans' Big Brains
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Recent research sequenced 48 bird species, including (from left) the budgerigar, the barn owl and the American flamingo. (Left and center)iStock; (Right) Chris Minerva/Ocean/Corbis hide caption

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Birds Of A Feather Aren't Necessarily Related
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