PCB4674 Exam 1 Dixon Spring 2026
Study online at https://quizlet.com/_j1ceav
1. Natural selection vs evolution: Natural selection is the process where individuals with heritable traits
that increase fitness leave more offspring. Evolution is change in allele frequencies in a population over generations.
2. What is population thinking?: The idea that variation exists among individuals in a population and that
evolution acts on that variation.
3. What is tree thinking?: The understanding that species share common ancestry and relationships can be
represented as branching phylogenies.
4. How do geographic patterns support evolution?: Species on islands and continents resem-
ble nearby mainland species, supporting descent with modification.
5. Name the three types of islands.: Continental islands, volcanic islands, and coral islands (atolls).
6. What is homology?: Similarity due to shared ancestry.
7. What is convergence?: Independent evolution of similar traits in unrelated lineages due to similar
selective pressures.
8. How can a trait be both homologous and convergent?: It can be homologous at one
evolutionary level but convergent at another (e.g., tetrapod limbs are homologous, but wings evolved convergently
within tetrapods).
9. What is a vestigial structure?: A reduced or nonfunctional structure inherited from an ancestor.
10. How does the fossil record support evolution?: It shows chronological change, extinction,
and transitional forms.
11. What are modern examples of evolutionary evidence?: Observed natural selection,
antibiotic resistance, pesticide resistance, and documented evolutionary change in wild populations.
12. Describe the steps of natural selection.: Variation exists; traits are heritable; individuals differ
in survival/reproduction; advantageous traits increase in frequency.
13. Why is genetics necessary for evolution?: Because evolution requires heritable variation and
changes in allele frequencies.
14. What did the Grants demonstrate in Darwin's finches?: Beak size evolved in response
to environmental changes, and the trait was heritable.
15. Why is estimating heritability difficult in field studies?: Environmental variation con-
founds genetic effects; parent and offspring may share environments.
16. What is uniformitarianism?: The principle that geological processes operating now also operated in
the past.
17. Who proposed natural selection independently of Darwin?: Alfred Russel Wallace.
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Study online at https://quizlet.com/_j1ceav
1. Natural selection vs evolution: Natural selection is the process where individuals with heritable traits
that increase fitness leave more offspring. Evolution is change in allele frequencies in a population over generations.
2. What is population thinking?: The idea that variation exists among individuals in a population and that
evolution acts on that variation.
3. What is tree thinking?: The understanding that species share common ancestry and relationships can be
represented as branching phylogenies.
4. How do geographic patterns support evolution?: Species on islands and continents resem-
ble nearby mainland species, supporting descent with modification.
5. Name the three types of islands.: Continental islands, volcanic islands, and coral islands (atolls).
6. What is homology?: Similarity due to shared ancestry.
7. What is convergence?: Independent evolution of similar traits in unrelated lineages due to similar
selective pressures.
8. How can a trait be both homologous and convergent?: It can be homologous at one
evolutionary level but convergent at another (e.g., tetrapod limbs are homologous, but wings evolved convergently
within tetrapods).
9. What is a vestigial structure?: A reduced or nonfunctional structure inherited from an ancestor.
10. How does the fossil record support evolution?: It shows chronological change, extinction,
and transitional forms.
11. What are modern examples of evolutionary evidence?: Observed natural selection,
antibiotic resistance, pesticide resistance, and documented evolutionary change in wild populations.
12. Describe the steps of natural selection.: Variation exists; traits are heritable; individuals differ
in survival/reproduction; advantageous traits increase in frequency.
13. Why is genetics necessary for evolution?: Because evolution requires heritable variation and
changes in allele frequencies.
14. What did the Grants demonstrate in Darwin's finches?: Beak size evolved in response
to environmental changes, and the trait was heritable.
15. Why is estimating heritability difficult in field studies?: Environmental variation con-
founds genetic effects; parent and offspring may share environments.
16. What is uniformitarianism?: The principle that geological processes operating now also operated in
the past.
17. Who proposed natural selection independently of Darwin?: Alfred Russel Wallace.
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