Today we will investigate how resource availability drives evolution by considering 13 species of Galapagos finches. Research on Daphne Major There are 13 different species of finch on the Galápagos Islands off the coast of Ecuador. On one of these islands, Daphne Major, biologists Peter and Rosemary Grant have devoted many years to studying four of these bird species. The Grants have studied the effects of drought and periods of plenty on the finches, and the results of their experiments have had an enormous impact on evolutionary science. In this activity, you will analyze some of the characteristics of the 13 species of finch found on the Galápagos Islands. Then you will watch a short film, “The Origin of Species: The Beak of the Finch,” about the research conducted by the Grants. The video is broken up into chapters, with discussion questions after each section. Based on the information presented in the film and your own observations, you will construct an argument and make predictions about the role of natural selection on the evolution of finch populations. Grouping by Morphology Grouping species according to shared characteristics can provide clues to how they have evolved. Morphological characters – characteristics of structure and form, such as size, shape, color – are often used for this purpose. Morphological Groups
Film: Part IWatch the first segment of the film, then answer the questions that follow.
Revising Morphological GroupsReturn to your finch groupings. Using information and evidence from the film, revise your groupings (if necessary). If you are happy with your original groups, you do not need to adjust them.
Film: Part IIWatch the second part of the film and answer the questions that follow.
Film: Part IIIWatch the third segment of the film and answer the questions that follow.
Film: Part IVWatch the final segment of the film and answer the questions that follow.
Natural Selection ScenariosSelect one of the scenarios below, and create a short presentation using the Google Slide template here: https://docs.google.com/presentation/d/1vFcvHN4wbr01PHaThvAc7j3M87lgUOvvKh0rQbBrwyg/edit?usp=sharing
Why was the scientific conclusion of common ancestry important for understanding the effects of natural selection?The conclusion that all Galápagos finches evolved from a single ancestral population was important because it suggests that one population evolved into 13 different ones.
What is the most likely explanation for the presence of 13 different finch species on the Galapagos Islands today?Which is the most likely explanation for the presence of 13 different finch species on the Galapagos Islands today? Many years ago several different species of birds migrated to the islands and the 13 finch species that currently live there are the only species that survived.
What evidence did scientists use to determine that the 13 species of finches on the Galapagos arose from a single common ancestor?Comparisons of DNA sequences revealed the evolutionary relationships among finch species. The data showed that all finch species living in the Galápagos Islands today are more closely related to one another than to any species of birds on the mainland, suggesting that they originated from a common ancestor.
On what did the Grants focus their research in the Galapagos Islands what observations did they make?The Grants study the evolution of Darwin's finches on the Galapagos Islands. The birds have been named for Darwin, in part, because he later theorized that the 13 distinct species were all descendants of a common ancestor.
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