Another Case of Evolution Before Your Very Eyes

Evolution need not take millions of years. We can (and do) witness it over the course of decades, and in some cases months in bacterial experiments. Here is but one of many recent stories illustrating “first hand” evolution.

Some communities of native Fence Lizards in the southeast U.S. have to contend with Fire Ants living in their immediate vicinity. Fire Ants represent an invasive species that was introduced to the region in the 1930s. Since that time, in approximately 80 years, researchers have noticed that the Fence Lizards who live with Fire Ants are evolving two things distinct from other Fence Lizard communities: 1) longer hind legs and 2) unique defensive behavior.

This is selective pressure in action! The lizards who have short legs (and therefore cannot shake off the ants effectively) or those who simply don’t respond to the attack die off and are weeded out of the gene pool. Those with longer legs survive to reproduce. It really is as simple as that.

Incidentally, this is precisely why things like allergies are on the rise within the human population. The selective pressure is there, in the form of life threatening anaphylaxis, but our medical knowledge and altruistic nature act as a dangerous safety valve. We achieve short term gain at the expense of long term survival.

Anyway, for the full lizard story, check out ScienceDaily.