British naturalist Alfred Russel Wallace (1823-1913) played a pivotal role in developing the theory of natural selection. But over time, Charles Darwin became almost universally thought of as the father of evolution. Wallace also called for protecting endangered species. Hulton-Deutsch Collection/Corbis hide caption

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An illustration shows how the planet Kepler-36c might look from the surface of the neighboring Kepler-36b. David Aguilar/Harvard-Smithsonian Center for Astrophysics/NASA hide caption

itoggle caption David Aguilar/Harvard-Smithsonian Center for Astrophysics/NASA

Will we need to tread lightly, in deference to the locals, when finally do make it to Mars? Pat Rawlings/SAIC/NASA hide caption

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Bonobos at the Lola ya Bonobo sanctuary near Kinshasa in the Democratic Republic of Congo in 2006. Issouf Sanogo/AFP/Getty Images hide caption

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Many of life's building blocks can be found in the objects bombarding Earth from outer space. Does that mean that life, too, developed elsewhere before arriving here? Mary P. Hrybyk-Keith/NASA hide caption

itoggle caption Mary P. Hrybyk-Keith/NASA

Alcohol: a key babyproofing product for this little mother. Illustration by Daniel M.N. Turner/Photos via istockphoto.com hide caption

itoggle caption Illustration by Daniel M.N. Turner/Photos via istockphoto.com

When times are tough, that prehistoric urge to splurge on high-calorie treats like M&Ms still kicks in. Daniel M.N. Turner/NPR hide caption

itoggle caption Daniel M.N. Turner/NPR

Thousands of years ago, a mutation in the human genome allowed many adults to digest lactose and drink milk. iStockphoto.com hide caption

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Can our nation afford political waffling on issues of scientific consensus? Stan Honda/AFP/Getty Images hide caption

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The first prehistoric chef who looked out at a field of grass in Africa and said, "dinner!" may have helped our ancestors use new resources in new locations. Roberto Schmidt/AFP/Getty Images hide caption

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Blaine Badick walks through floodwaters with her dogs in Hoboken, N.J., on Wednesday. Brendan Smialowski/AFP/Getty Images hide caption

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Actors Stan Laurel and Edna Marlon play at socializing around the campfire. It turns out that early man's brain developed in part thanks to cooking. Hulton Archive/Getty hide caption

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