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(0)Peter and Rosemary Grant
Description
This program begins with spectacular scenery of the Galápagos islands, including a volcanic eruption. It introduces the idea of the archipelago being extremely dynamic geophysically and biologically, on both short and long time scales. It then illustrates the rich biodiversity of the archipelago with examples of plants, birds and insects from the small island of Daphne, and fish, sea-lions and sea birds in the marine environment nearby. The program...
Description
Methods of studying finches are described, illustrated and explained in this program. The key activity is capturing birds in mist-nets in several locations around the island. The nets are put up in late afternoon, opened before dawn, and finches that have flown in and captured are removed. They are taken to a shady cave where they are weighed, measured and banded for later individual identification. The program shows how a small drop of blood is taken...
Description
New species form in the Galápagos when populations of the same species diverge from each other on different islands, then later come together on the same island. This program reveals the barrier to interbreeding between different species of Darwin's finches. It examines why the barrier sometimes leaks and the consequences of rare gene exchange between species. The premating barrier to interbreeding is based on song learned early in life in association...
Description
The Galápagos experiences a strongly seasonal environment. Finches breed when the rains arrive, typically in January or February. In some years there is no rain and no breeding. This program illustrates the various ways that environmental fluctuations dictate the activities of finches on Daphne. It follows the stages of the breeding cycle, from pair formation and nest building a few days after the first heavy rainfall to fledging about a month later....
Description
When species exchange genes by interbreeding their morphological and genetic variation increases. Unusual or extreme variants are produced that could be the starting point of a new evolutionary trajectory leading to the formation of a new species. This program illustrates this with finches on Daphne. A hybrid male from the nearby island of Santa Cruz immigrated to Daphne. It was larger than the parental species, Medium Ground and Cactus Finches, it...
Description
This short program illustrates how investigators live on Daphne. It starts with their arrival at Daphne and shows the difficulties of transferring supplies from boat to land and up a cliff because the island that has no beaches. All supplies are quarantined before arrival. Living is in a tent and cooking is done in a small cave with a shade erected to extend protection from sun and rain. There is no fresh water on the island and it has to be brought...