Anole Lizard Urban Adaptation

Explore how urbanization (smooth surfaces and heat) acts as a selective pressure, driving natural selection and changing the physical form (toe pad size) of an Anole lizard population over generations.

Environmental Controls

Affects surface types. High urbanization = smooth, hot metal/concrete. Low urbanization = textured, cool forest bark.

Simulation Controls

Current Status

Generation: 0

Population: 100

Avg Toe Pad Size: 10.0 mm

Island Ecosystem

Smooth/Hot (Urban)
Textured/Cool (Forest)

Toe Pad Size Distribution (Current Gen)

Average Toe Pad Size over Time

The Science: Adaptation and Form

This simulation demonstrates natural selection and rapid adaptation, focusing on how urbanization acts as a selective pressure. It is based on real-world studies of the Puerto Rican crested anole (Anolis cristatellus) adapting to urban heat islands like San Juan.

How it works:

  • Variation: The anole population naturally has a variety of toe pad sizes (measured in relative units).
  • Environment (Urbanization): Urbanization dictates the available surfaces. High urbanization creates an abundance of smooth, hot surfaces (metal, glass, concrete). Low urbanization means mostly textured, cool forest bark.
  • Selection: Anoles with large toe pads and longer limbs can better grip smooth urban surfaces and tolerate heat. Anoles with smaller toe pads are better adapted to grip the rough texture of forest trees.
  • Reproduction: Anoles that can effectively navigate their environment and escape predators survive and reproduce, passing their toe pad size trait to their offspring (with slight random mutations).

By observing the population over multiple generations, you can see adaptation in real-time as the population's physical form shifts to match the demands of the environment.