How do cells know what they should become as the body develops? Biological development depends crucially on spatial patterns: the lines that eventually give rise to segments, organs, or markings like ...

In most vertebrates, skin appendages such as hair, feathers, or scales originate from placodes—small, specialized skin regions whose spatial organization is controlled by well-conserved genetic ...

ch. 1. Ode to Cecropia: discovering nature -- ch. 2. Teasing the strands apart -- ch. 3. Time, energy, and biological evolution -- ch. 4. Evolution of the earth -- ch ...

The concept of punctuated equilibrium was, to some, a radical new idea when it was first proposed by Stephen Jay Gould and Niles Eldredge in 1972. Now it is widely recognized as a useful model for one ...