Anole lizards occur across the Caribbean and the nearby mainland, and the genus includes many species. With the exception of Anolis carolinensis, which is present in mainland Florida, each species is restricted to a single island or to a small cluster of islands. Fig. 5.1 illustrates where four species of anole lizards are found. A study was then carried out on the relationships among these four species by means of DNA analysis. The base sequences of a section of mitochondrial DNA from the four species were compared, and the findings are given in Table 5.1. A smaller number indicates a smaller difference between the base sequences of the two species.
(a)[1]
Using Table 5.1, state which species A. brunneus seems to be most closely related to.
(b)[3]
The researchers proposed the idea that the three species, A. brunneus, A. smaragdinus and A. carolinensis, arose from three different events in which a few individuals of A. porcatus dispersed directly from Cuba to three separate locations. Explain how the data in Table 5.1 support the researchers’ idea.
(c)[4]
Explain how an A. porcatus population that became isolated on an island could develop into a new species.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “$A.\ porcatus$” …