For many creatures, embryonic development involves the amazing unfolding of a single cell into an animal with billions of cells, each with a specific structure and function. How does a small ball of identical dividing cells know when to start or stop its growth, as well as when or where (not to mention how) to begin differentiating into various types of tissues?

Human eyes are well-designed to see objects using light transmitted through air, but not through water, because light travels at a different speed through the two media. However, intertidal-dwelling marine mollusks called chitons can see equally well in both environments. How did they acquire this unusual ability?

When two species of daisy are crossed, the resulting daisies should look a little like each parent…right?

The human hand is undeniably a work of wonder. Its layout and suite of design features enable mankind―the only possessors of this particular arrangement of bones, tendons, muscles, and nerves―to type faster than 60 words per minute or swing a heavy hammer while holding a delicate potato chip. What would it take to duplicate a human hand?

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?