EVOLUTION
Due: 4/26
Read the Introduction and chapters 22-26 in Campbell.
Key Terms: evolution by natural selection evolution by the inheritance of acquired
characteristics
gene pool
acquired characteristics
allelic frequency
genetic equilibrium
genotype frequencies
genetic drift
mutation pressure
selection pressure
polygenic characters
disruptive selection
balanced polymorphism
adaptation
coevolution
warning coloration
mutualism
population
species
cline
race
founder effect
sympatric
habitat isolation
behavioral isolation
reproductive isolation
sympatric speciation
punctuated equilibrium
convergence
Hardy-Weinberg Law
neutral selection
gene flow
preadapted
directional selection
stabilizing selection
heterozygote superiority
fitness
cryptic appearance
commensalism
parasitism
deme
intraspecific variation
subspecies
speciation
allopatric
ecogeographic isolation
seasonal isolation
geographic isolation
polyploidy
evolutionary bottleneck
gradualism
Answer the following questions:
1. List the processes that can lead to variation in the genetic material, and explain why
changes that affect only somatic cells, such as variations produced by practice,
education, diet, or medical treatment, cannot bring about evolution. Contrast
Lamarck's theory of evolution by the inheritance of acquired characteristic with
Darwin and Wallace's theory of evolution by natural selection.
2. Explain the concept of the gene pool. Given the frequency of two alleles,
(A = 0.9, a= 0.1) calculate the ratios of the genotypes produced by them, using a
Punnett square or the algebraic formula. Assume that both parents are
heterozygous (Aa x Aa).
3. State the Hardy - Weinberg Law, and discuss its four conditions for the maintenance
of genetic equilibrium, describing the forces that prevent these conditions from
being fulfilled. In doing so, use the following terms: genetic drift, mutation, gene
flow, selection pressure, and random reproduction.
4. Explain how natural selection on a phenotype in one generation can affect the
genotype of the next generation , and calculate how changes in allelic frequencies
in the parental generation can alter allelic frequencies in the offspring.
5. Using diagrams, contrast directional selection, stabilizing selection, and disruptive
selection. Indicate which type or selection is involved in the experiment.
6. Contrast the roles of selection and mutation in directing evolutionary change.
Indicate other factors that may be important in evolution.
7. Using an example, explain how a characteristic can have both positive and negative
effects, and indicate what determines whether or not the frequency of a trait will
increase or decrease in the population. Include a discussion of heterozygote
superiority, showing how this condition affects the fate of certain alleles.
8. Define adaptation and fitness in their evolutionary sense, and explain, using
examples, how such phenomena as flower structure, defensive secretions, cryptic
appearance (including polymorphism), warning coloration, and mimicry are
adaptive.
9. List the three types of symbiotic interactions, and show how they differ from one
another. Distinguish between external and internal parasites, and discuss two
adaptations of internal parasites. Explain why most well-adapted parasites do not
generally kill or seriously harm their host species.
10. Discuss intraspecific geographic variation; in doing so, distinguish among the
following : population, race or subspecies, and cline.
11. Give a definition of a species and, explain the geographic isolation model of
divergent speciation. In doing so, be sure to take into account the roles of mutation,
recombination, natural selection, and the gene pool.
12. Differentiate between sympatric speciation and allopatric speciation (see index /
glossary).
13. Explain what is meant by adaptive radiation, and discuss the evidence for this
phenomenon, using the Galapagos finches as an example.
14. Contrast the role of competition and natural catastrophes on the evolution of natural
populations, explaining what is meant by an evolutionary bottleneck. Indicate which
of the above is believed to be the predominant force leading to speciation over time.
15. Compare the hypothesis of punctuated equilibrium with that of gradualism, and give
an example supporting each hypothesis.
16. Distinguish among divergent, parallel, and convergent evolution, and give examples
of each. Explain the difference between homologous and analogous structures.
17. List in order the categories of the classification hierarchy used today. Then explain
how a species is named. (see Chapter 25)