Anole lizards together with cichlid fishes and Darwin’s finches are one of the star organisms in studying a rapid evolution pattern called adaptive radiation.
Jonathan Losos is a veteran field biologist that has studied the traits that enable dozens of anole species to adapt to different niches in the islands of the Caribbean. Differences in limb length, body shape, and toepad size allow different species to be successful on the ground. However on vegetation surfaces such as thin branches, or higher up in the canopy, changes in other traits including dewlap color, have played a key role in reproductive isolation and the formation of new species.
Here in this Howard Hughes Medical Institute (HHMI) documentary series from the Biointeractive we tag along field ecologists and see how evolution can be studied in their natural settings including controlled natural experiments where organisms are introduced to small uncolonized islands to observe how traits change in time. Fascinating discovery was that under isolation each island had evolved similar body types independently. Biologists call this type of change convergent evolution.
Anole lizards continue to be an important model system for studying evolution. Hurricane-induced natural selection is one of them. Such catastrophically destructive natural events bring long-lasting effects on ecological systems. In 2017, immediately after a survey of Anolis scriptus —a common, small-bodied lizard found throughout the Turks and Caicos archipelago — Hurricanes Irma and Maria brought destruction to the Caribbean. Scientists took this opportunity and revisited the surveyed populations to determine whether morphological traits related to clinging capacity had shifted in the intervening six weeks. Indeed they found that populations of surviving lizards varied in body size, relative limb length and toepad size from those living before the storm. Therefore hurricanes can induce fast phenotypic change though natural selection.
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