This activity supports the film The Origin of Species: Lizards in an Evolutionary Tree. Students are guided to sort the lizard species by appearance, then generate a phylogenetic tree using the lizards’ DNA sequences to evaluate whether species that appear similar are closely related to each other.
In the film The Origin of Species: Lizards in an Evolutionary Tree, Jonathan Losos explains that the Caribbean anole lizards can be classified into different types based on appearance, but if you analyze their DNA, species from different islands that appear similar are not closely related. Instead, species on the same islands that look different are closely related. Thus, it appears that different types of anoles evolved independently on each island—a phenomenon called convergent evolution.
Students can follow the same research rationale and draw their own conclusions. First, they will be guided to examine photographs of 16 species of anoles and group them into different types. Then after watching the film, they will generate the phylogenetic tree of the 16 species using their DNA sequences and a simple-to-use phylogeny website. The DNA-based phylogeny will show that lizards that are from the same island are closely related to each other, even though they have different body types, and conversely, the lizards that look similar on different islands are not necessarily closely related to each other. It’s a great example of convergent evolution.
NGSS (April 2013)
MS-LS1-5, MS-LS4-2, MS-LS4-4, MS-LS4.A, MS-LS4.B, MA-LS4.C, HS-LS4-1, HS-LS4-2, HS-LS4-3, HS-LS4-4, HS-LS4-5, HS-LS4.B, HS-LS4.C, HS-LS4.D
1.A.1, 1.A.2, 1.A.4, 1.B.2, 1.C.1, 1.C.2, 1.C.3
5.1, 5.4, D2, D5