Honors Biology Reading Guide Chapter 13: How Populations Evolve
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Chapter 13: How Populations Evolve
Section 13.1 A sea voyage helped Darwin frame his theory of evolution
1. How did Aristotle view species?
2. For centuries, what two ideas where dominating the western world?
3. In the early 1800s what did Jean Babtiste Lemarck suggest for the best explanation for the relationship between fossils and current organisms?
4. What was Lemarcks explanation for how species evolved?
5. Although Lemarcks explanation for how species evolve was incorrect, his thinking has been influential. What is considered to be the great importance of his ideas?
6. What observations did Darwin make upon his visit to the Galapagos Islands?
7. After returning to Great Britain, what doubts did Darwin have about the world?
8. What conclusions did Darwin come to based on his doubts?
9. What evidence did Darwin present for his explanation for evolution?
10. Explain “descent with modification”.
11. What mechanism did Darwin propose for descent with modification?
13.2 Darwin proposed natural selection as the mechanism of evolution
12. Compare artificial selection and natural selection.
13. What 2 observations did Darwin make that led him to formulating his theory of evolution by natural selection?
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2)
14. Based from these 2 observations, Darwin was able to draw 2 conclusions that are the foundation to natural selection. What conclusions, or inferences, did Darwin come to?
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15. Evolution by natural selection can become a very complex process to understand with many different part influencing how organisms evolve. However, we can narrow the process of evolution by natural selection down to 3 key points. Describe the 3 KEY points to evolution by natural selection.
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13.3 Scientists can observe natural selection in action
16. Often times being able to actually observe evolution by natural selection can prove to be very difficult. However, there are several examples in which biologists have been able to observe and document the evolution of species. For the below 2 examples explain how they demonstrate evolution by natural selection.
1) Galapagos Finches
2) Pesticide resistance in insects
17. Earlier we looked at the 3 key points to how evolution works. Now lets look at 3 Key points to how natural selection works in order to cause evolution.
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13.4 The study of fossils provides strong evidence for evolution
18. We often times think of fossils that paleontologists collect as being hard and rock like. However, there are many different forms that a fossil can take other than a hard rock like substance. Explain 2 other types of fossils besides hard, rock-like.
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2)
19. Explain what a fossil record is.
20. Describe strata.
21. Describe the location of the oldest strata relative to the newest strata.
22. What type of information can be obtained about a fossil found in a particular strata?
23. What does the fossil record reveal?
24. At the time of the publication of Darwin’s The Origin of Species there was a severe lack of fossil evidence showing how previous groups of organisms gave rise to new groups of organisms. However, since the publication of The Origin of Species many fossils have been collected showing how previous groups of organisms gave rise to new groups of organisms. Explain the evidence that supports the evolution of modern day whales from their four-legged ancestors.
13.5 A mass of other evidence reinforces the evolutionary view of life
25. Explain what the below pieces of evidence are, how they support the evolutionary view of life, and provide an example.
a) Biogeography
b) Comparative anatomy
c) Molecular biology
13.6 Homologies indicate patterns of descent that can be shown on an evolutionary tree
26. To help us visualize the evolutionary relationships between organisms we make use of evolutionary/phylogenetic trees. What is summarized in an evolutionary tree?
27. What is represented at the tips of the tree? What is represented at the trunk of the tree?
28. What information is used to create an evolutionary/phylogenetic tree?
29. To get a better understanding of how an evolutionary/phylogenetic tree works lets do some practice on how to read one. Using figure 13.6 in your textbook and the below diagram that shows an evolutionary/phylogenetic tree answer the following questions.
a) What is indicated by each branch point?
b) What is indicated by the hatch marks?
c) Are crocodiles more closely related to lizards or to birds? Justify your response.
d) On the above tree, label the vertical columns to the right and annotate the key features that marks each group.
13.7 Populations are the units of evolution
30. What is a common misconception and mistake people make about evolution?
31. It is true that natural selection acts on an individuals traits affecting their survival and reproductive success. However, the evolutionary impact that natural selection has only becomes apparent when what happens?
32. Explain what a population is.
33. How can we measure evolution?
34. What time frame do we use to measure evolutionary change?
35. What do biologist focus on when trying to determine if evolution has occurred in a population?
36. What does a gene pool consist of?
37. What do we call evolution that occurs on the genetic level?
38. How do we determine if evolution has occurred on the genetic level?
39. To demonstrate your understanding of this section, complete the following sentences:
do not evolve. evolve.
13.8 Mutation and sexual reproduction produce genetic variations, making evolution possible
40. Darwin provided ample evidence that life has evolved over time and the mechanism for that change was natural selection. However, Darwin was unable to explain how populations obtained the variations in the traits within a population that natural selection acted. Nor was he able to explain how those variable traits were passed on from one generation to another. Although not realized in his or Darwin’s time, what individual laid the groundwork that was necessary to understanding how populations evolve by natural selection.
41. An individuals phenotype is the result of what two factors?
42. How do new alleles arise in a population thus acting as the ultimate source of new variations within a population?
43. Describe what a mutation is.
44. In multi-celled organisms, where is the only place in which a mutation can occur in order for evolution to have an affect? Explain.
45. In plants and animals, what prevents most genetic mutations from significantly affecting genetic variations from one generation to the next?
46. If mutations cannot significantly influence genetic variation within a population (in sexually reproducing organisms), what does?
13.9 The Hardy-Weinberg equation can be used to test whether a population is evolving
47. Now that you have obtained this wealth of knowledge of what evolution is and what causes evolution, how can we tell if evolution is actually occurring in a population? Luckily for us Hardy and Weinberg developed a way for us to determine if a population is evolving or not, it is called the Hardy-Weinberg equilibrium/principle. We can make use of 2 mathematical formulas to help us. The first is a formula used to determine the frequency of alleles in a given population, p + q = 1. In this formula what does p and q represent?
48. We can also use the mathematical formula p2 + 2pq + q2 = 1 to look at the frequencies of the different genotypes in our population. In this formula what does p2, 2pq, and q2 represent?
49. So how exactly do these 2 formulas and Hardy-Weinberg equilibrium/principle help us determine if a population is evolving? The Hardy-Weinberg equilibrium/principle describes as population, or gene pool, that IS NOT evolving. In other words, the allelic frequencies and genotypic frequencies WILL NOT change over generations. If the frequencies do change what has occurred?
50. However, in order for a population to be in Hardy-Weinberg equilibrium, it must satisfy 5 main conditions. What are those 5 conditions?
51. Using the blue-footed boobies that your book explains as an example let’s just see if you can make use of the mathematical formulas to determine the frequencies of the alleles and genotypes in a population.
We have a of 737 boobies; of these, 500 birds have the genotype WW, 220 have the genotype Ww, and 17 have the genotype ww. What are the frequencies of each of these genotypes?
What are the frequencies of each of the alleles in this population?
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