Download HOMEWORK 01: ANSWER KEY

BIO 295
Islands & Evolution
- from the Galapagos to New York City
HOMEWORK 01: ANSWER KEY
The Beak of the Finch: Chapters 1-3
Answer each question in at least one paragraph (ca. 150-200 words). Refer to the syllabus (section “Written
assignments”) for formatting instructions.
1. What makes Daphne Major and the Galapagos unique? Who are Peter and Rosemary Grant
and why did they choose this place to find support for Darwin’s theory?
Size, simplicity, isolation, age of islands (factors that make islands interesting for studying evolution);
Daphne major chosen because of “inconveniences”, small enough to know all birds, large enough to get
good numbers; evolutionary biologists at Princeton University
p. 9-14, 19
p.16
2. Describe the study system (Darwin’s finches).
Study system = organism/s that is/are studied i.e. Darwin’s finches
Number of finches and names, notes on biology of different species, variability between species
(especially beaks)
p. 17-18, 41-43
3. How did Darwin end up going to the Galapagos Islands and what were his impressions? How
did his stay on the islands change his ideas? What role did the finches play in this process?
Darwin joined the Beagle to collect specimens, observed interesting patterns in island inhabitants
(mocking birds, tortoises, not finches!), read Principles of Geology and started thinking about ongoing
change, his observations and collections eventually got him thinking about the origin of species; Story
that finches played crucial role in shaping Darwin’s ideas on evolution is a fable, truth is they played a
minor role, Darwin did not even mention the finches in his final draft of the Origin
p. 21-30
p. 35-36, 40 (bottom)-41
4. Why did people think that evolution moved too slowly to ever be observed? What kinds of
experiments did Darwin conduct to provide proof for his theory? Was he successful?
Evidence of evolution had only been found in the fossil record; Darwin started breeding pigeons to see
the process of selection firsthand, successful in documenting artificial selection but his peers did not
accept these experiments as proof of his theory of evolution by natural selection
p. 6, 7
p.30-35
5. How did the finch study begin? What triggered the start of the long-term study?
Finch study = long-term study conducted by the Grants (not Darwin who only “opened their eyes to
the process”, p. 36)
Peter Grant interested in variation, wanted to watch what happens in nature, “needed group of
hypervariable species, well-studied, variability variable, scattered across set of remote and undisturbed
locations”, found Galapagos and thought they were ideal, first trip in 1973, intended to stay only one
season, found interesting pattern when measuring finches, decided to continue
p. 3 (bottom)
p. 37
p. 43-48
6. In what situation could the tameness of the birds on the island become a problem? This is a
relevant concern for island-inhabiting species in general.
Not specifically mentioned in book. Human presence could cause problem but main problem when new
predator is introduced, birds did not have time to evolve any defensive mechanisms, could be quickly
driven to extinction
p. 44-45
7. Why do you think it took so many years for scientists to document evolution in action after
Darwin’s Origin of Species was released?
Many possible answers. For instance, religion, technology, stubbornness (a lot of things are easy to do
once they have been done before, the pioneers need to be stubborn and have patience)
p.36 (bottom)
Assigned 01/27
Due 02/04 5pm (submit electronically)