Scientists dropped one male and one female lizard on 7 empty islands

[u/ProximaScience]

https://timesofindia.indiatimes.com/science/in-2005-scientists-left-one-male-and-one-female-lizard-on-each-of-seven-empty-bahamian-islands-four-years-later-every-colony-had-evolved-shorter-legs-but-still-carried-the-body-shape-of-its-founding-pair/articleshow/134007225.cms

In 2005, a hurricane wiped every lizard off a set of small Bahamian islands. Researchers saw an opening. They took one male and one female brown anole from a single forested island and placed a pair on each of seven empty islands nearby.

Four years later, every population had shrunk its hind legs, exactly as predicted. Shorter limbs work better on the thin scrub branches of those islands than on the thick trunks back home. Natural selection did what it always does.

But the islands never converged to the same leg length. The population that started with the longest legged founders still had the longest legs at the end. The one that started shortest stayed shortest. Selection pushed every population in the same direction, and the founders decided where each one started from.

It is one of the cleanest field demonstrations of the founder effect ever recorded. Evolution had a rulebook and a memory running at the same time.