Darwin’s Finches and Natural Selection. by Cheryl Heinz, Dept. of Biological Sciences, Benedictine University, and Eric Ribbens, Dept. of Biological Sciences, Western Illinois University. The Galapagos Islands. Located approximately 1000km from the coast of Ecuador, South America.
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Cheryl Heinz, Dept. of Biological Sciences, Benedictine University, and Eric Ribbens, Dept. of Biological Sciences, Western Illinois University
A: Birds rarely move between the mainland and the islands.
B: Birds on the island have the same genes as birds on the mainland.
C: Birds on the mainland don’t like birds from the islands.
D: Birds on the mainland won’t evolve, but birds on the islands might.
Among the kinds of animals found here and nowhere else:
A: The end is imminent.
B: The species isn’t found anywhere else.
C: The species has very specific habitat requirements.
D: The species needs to be protected.
E: The species is extinct.
A: about 7mm
B: about 8mm
C: about 9.5mm
D: about 10mm
E: about 11mm
A: 2 mm
B: 4 mm
C: 6 mm
D: 8 mm
E: 10 mm
CQ5: What do you think a graph of population size would look like for Year 1 to Year 3?
A: Just under 7mm
B: About 8mm
C: About 9mm
D: Just under 10mm
E: Just under 11mm
A change in the frequency of an allele, such as an allele for beak depth, is the basic definition of evolution.
D: I don’t know
Two things surprised the Grants:
2. Evolution can occur at very small scales.
The Grants’ measurements were very careful.
A: Evolution occurs at a rate that we humans can observe.
B: As little as half of a millimeter can make the difference between life and death.
C: Both surprise me.
D: Neither was particularly surprising.
2. Some of the differences in traits are passed along to offspring.
3. Different individuals produce different numbers of surviving offspring.
4. The particular value of a trait is connected to the number of offspring produced.
CQ9: If beak depth increased during the drought, primarily due to selective mortality, can we really say that this natural selection was driven by environment favoring the survival of birds with deeper beaks?
A: No. Beak depth changed due to birds dying, not to birds surviving.
B: Yes. Birds with deeper beaks survived at a higher rate than birds with shallower beaks.
C: I’m really confused.
The Beak of the Finch: A story of evolution in our time, by Jonathan Weiner (New York: Knopf, 1994).