LOOK WHO’S COMING FOR DINNER: SELECTION BY PREDATION
PART I: INTRODUCTION
In the film The Origin of Species: Lizards in an Evolutionary Tree, you met the anole lizards of the Caribbean islands.
For well over 20 years,
...
LOOK WHO’S COMING FOR DINNER: SELECTION BY PREDATION
PART I: INTRODUCTION
In the film The Origin of Species: Lizards in an Evolutionary Tree, you met the anole lizards of the Caribbean islands.
For well over 20 years, Dr. Jonathan Losos has studied these lizards to understand how the different species and
their traits have evolved. In this activity, you will examine the results from an experiment that involves another
type of lizard, the much larger curly-tailed lizard that hunts and feeds on anoles!
Figure 1: This map of the Caribbean Islands features Cuba, Jamaica, Hispaniola (Haiti and the
Dominican Republic), Puerto Rico, and the Bahamas. The inset shows Great Abaco Island in the
northern Bahamas. (Adapted from MapMaker Interactive maps, National Geographic Society,
http://mapmaker.education.nationalgeographic.com/)
Dr. Losos and his colleagues conducted an experiment in a group of small islands near Abaco in the northern
Bahamas (Figure 1), where a single species of anole, Anolis sagrei, lives. A. sagrei is a long-legged species of anole
that spends most of its active time on the ground or on the lower parts of tree trunks, where it hunts for prey
and mates with other A. sagrei lizards. Although in general A. sagrei lizards have relatively long legs compared to
other species of anole lizards, leg length varies among individuals in a population.
On some islands, A. sagrei coexists with Leiocephalus carinatus, a large, curly-tailed lizard that hunts for prey,
including anoles, on the ground. On these islands, Dr. Losos and his colleagues noticed that A. sagrei lizards tend
to spend more time on bushes and small trees where L. carinatus cannot climb (Figure 2)
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