About 15 million to 20 million years ago, anoles were trapped in tree resin on what is now the island of Hispaniola, home to Haiti and the Dominican Republic.

Anoles still live in abundance on the island and throughout the Caribbean. Jonathan Losos, an evolutionary biologist at Harvard, has studied them for decades.

These lizards, as he has documented, occupy very specific bits of space on trees in rain forests. One species may live from the ground up to six feet high on the trunk, another species from six feet up the trunk to the crown, and another in the crown.

And although there are many different species on different islands, they fall into categories that characterize not only their behavior but their body structure. These forms — body types shaped by ecological niches — are called ecomorphs. The niches and the ecomorphs are the same in anole communities from island to island.