Evolution Review

Topics / Concepts:

· evidence for evolution (fossils, biogeography, comparative anatomy (homologous vs analogous), molecular homologies, etc.)

· Darwin and natural selection (plus Darwin’s influences, and Darwin vs. Lamarck)

-  examples of natural selection in action

· Hardy-Weinberg equilibrium

-  what does it mean/show?

-  What 5 things have to occur for a population to be in Hardy-Weinberg?

· 5 causes of evolution

-  genetic drift, gene flow, mutations, nonrandom mating, natural selection

· modes of selection (stabilizing, directional, diversifying, sexual selection)

· speciation

· prezygotic vs postzygotic barriers

· allopatric vs sympatric speciation modes

· divergent/adaptive radiation vs convergent evolution

· gradualism vs. punctuated equilibrium

Review Questions:

1) Porcupines use their quills to scare off potential predators/enemies. Explain how this specific trait evolved in porcupines using:

a)  Larmarck’s ideas:

b)  Darwin’s ideas:

2) Distinguish between genetic drift and gene flow.

3) Identify whether the following are pre- or postzygotic barriers.

Pre- or Postzygotic / Example
Two species of frogs are mated in the lab and produce viable, but sterile, offspring.
Two species of sea urchin release their gametes at the same time, but cross-specific fertilization does not occur.
Two species of orchid have different length nectar tubes and are pollinated by different species of moths.
Two species of mayflies emerge during different weeks in springtime.
Two species of salamanders will mate in the lab and produce viable, fertile offspring, but offspring of these hybrids are sterile.
Two similar species of birds have different mating rituals.
When two species of mice are bred in the lab, embryos usually abort.
Peepers breed in woodland ponds, whereas leopard frogs breed in swamps.

4) Is evolution random or goal-oriented? (i.e. is there some ultimate goal or grand plan for evolution?) Explain.

5) Compare the gradualism and punctuated equilibrium theories/models of evolution.

6) What are fossils?

In what type of rock are most fossils found?

How is this type of rock formed?

How is fossil age related to position in the rock layers?

7) Compare natural and artificial selection

8) Complete the following chart for the various lines of evidence supporting evolution:

Line of Evidence

/ Explanation (What is it? How does it support evolution?) / Example
Biogeography
Fossil Record
Homologous structure
Vestigial organs
Comparative embryology
Molecular biology

9) An orange grower discovered that most of his trees were infested with destructive mites. He sprayed the trees with insecticide, which killed 99% of the mites. Five weeks later, most of the trees were infested again, so he sprayed again, using the same quantity of the same insecticide. This time, only about half the mites were killed. Explain why the spray did not work as well the second time.

10) Do individual organisms evolve?

11) List and describe the five causes of evolution?

12) Describe the phenomenon known as “The Bottleneck Effect,” and give an example.

13) What is the founder effect?

14) Complete the following chart comparing different types of selection:

Type of selection / What is it? (Explain) /

Example

Stabilizing selection
Directional selection
Disruptive/Diversifying selection
Sexual selection