Natural selection

The brown anole (Anolis sagrei) is a type of lizard that is native to islands in the Caribbean Sea. These lizards can live in a variety of habitats. Ground-dwelling populations of brown anoles live on lower parts of tree trunks and on the ground. These populations have long legs that help with jumping. Other anole lizard populations live higher up on tree trunks. These populations have short legs that help with perching.

Curly-tailed lizards (Leiocephalus carinatus) are a predator of the brown anole. A group of researchers introduced these predatory lizards into the habitat of certain ground-dwelling brown anoles. To avoid these predators, many individuals from the ground-dwelling populations of brown anoles began to move higher into trees.

Based on the information above, which of the following is the best prediction for what will happen over time to the populations of ground-dwelling brown anoles in areas where curly-tailed lizards were introduced?

(Choice A)
Over many generations, the brown anole populations will likely develop shorter legs as they adapt to living higher in trees.
(Choice B)
Because of their selective advantage, brown anoles that remain on the ground will likely produce more offspring in each generation than brown anoles that move higher in trees.
(Choice C)
Within two or three generations, the brown anoles will likely become extinct due to predation by curly-tailed lizards.
(Choice D)
The brown anole populations will likely develop longer legs over many generations as they adapt to jumping higher up in trees.

Losos, Jonathan B., Thomas W. Schoener, and David A. Spiller. 2004. “Predator-Induced Behaviour Shifts and Natural Selection in Field-Experimental Lizard Populations” Nature 432(7016):505-8. https://doi.org/10.1038/nature03039

Losos, Jonathan B. 1994. “Integrative Approaches to Evolutionary Ecology: Anolis Lizards as Model Systems" Annual Review of Ecology and Systematics 25:467–93. https://doi.org/10.1146/annurev.es.25.110194.002343.

Biology library

Course: Biology library > Unit 26

Problem