Darwinian evolution asserts that a single original organism morphed over countless generations into the modern known life forms. Each species alive today would therefore represent the tip of its own "branch" on a gigantic imaginary tree of life, with the hypothetical ancestor of all life forms situated at the base of the trunk.

Unlike other creatures, humans can compose, record, and enjoy music. A new study has identified a brain chemical that provides pleasure when people listen to certain music. Where did this amazing ability come from?

When boring into wood in search of food, a woodpecker exerts so much force with each strike that its beak should crumble, its skull should crack, and its brain should be reduced to mush. However, a suite of design features absorbs the shock and ensures that these tragedies do not happen. How are these features able to provide such effective protection?

Among land-dwelling arthropods, the sheer number of just ants and beetles that live and die each year is phenomenal. And ocean krill exist in even higher numbers. Each of these creatures leaves behind an exoskeleton. If it were not for remarkably efficient exoskeleton-eating microbes, the earth would quickly fill up with arthropod carcasses.

For years, museum displays have featured the small extinct ape Australopithecus afarensis. The first specimen, discovered in 1974 and nicknamed "Lucy," was presented as having clearly human eyes, feet, and posture. The feet and posture, however, can only be verified by relevant fossilized structures.