Evolution At A Fast Rate

Scientists around the world are celebrating the 200th birthday of British naturalist Charles Darwin, who was born on Feb. 12, 1809. Darwin’s groundbreaking 1859 book, “The Origin of Species,” proposed the theory that species evolve over time through the process of natural selection. Organisms most suited to their environment survive and reproduce, passing on their advantageous traits to offspring. Organisms that cannot compete go extinct. Though this theory remains a hot potato in the culture wars, it forms the foundation of modern biology.

We think of evolution being a gradual process of change that happens over many, many years. Here are a couple of examples of evolution in the fast lane.

Butterflies rapidly evolve resistance

to killer bacteria

A population of tropical butterflies on a South Pacific island evolved resistance to a killer bacteria in the span of a single year – a blink of the eye in evolutionary time. The bacteria infects females and selectively kills males before they hatch. The strategy reduced male Blue Moon butterflies to just 1 percent of the population. But just 10 generations later – a year's time – males made up nearly 40 percent of the population. Scientists said the rebound is due to the evolution of a so-called suppressor gene that keeps the killer bacteria in check

Toxic toad evolves longer legs

A toxic toad, the Cane Toad- Bufo marinus, introduced in 1936 to wipe out a beetle species wreaking havoc on Australia's sugar cane crop, has become an uncontrollable pest itself, evolving longer legs to help it hop across the country at an ever-increasing clip. For their first 20 years or so in the country, they spread at a pace of 6 miles per year. They now cruise at about 30 miles per year. Why? Researchers found that the toads leading the cross-country march had legs that were 6 percent longer than those of the stragglers. The added length gives more speed, which permits the long-legged toads to secure the best habitat at the newly conquered terrain.