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| 1. |
Section 2.2 presented two definitions of homology: the classical definition articulated by Richard Owen and the modern definition favored by many contemporary biologists. Look at the vestigial organs whown in Figure 2.2. Is the empty eye socket of a blind cave fish homologous to the functional eye of a surface fish? Is the tiny wing of a brown kiwi homologous to the wing of an eagle? Are the spurs of a rubber boa homologous to the hind limbs of a kangaroo? By which definition of homology?
[Hint]
To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
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| 2. |
Analogy and homology are important concepts used in comparing species. Traits are homologous if they are derived, evoltuionaryily and developmentally, from the same source structure. Traits are analagous if they have similar functions but are derived, evolutionarily and developmentally, from different source structures. A classic example of analogous structures is insect wings and bat wings. Which of the following pairs of structures are analogous, and which are homologous?
a) The dorsal fins of a porpoise and a salmon.
b) The jointed leg of a ladybird beetle and a robin.
c) A siamang ape's tail and a human's coccyx.
d) The bright red bracts (modified leaves) of a poinsettia and the green leaves of a rose.
e) The bright red bracts of a poinsettia and the red petals of a rose.
[Hint]
To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
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| 3. |
In the early 20th century, radiometric dating allowed geologists to assign absolute ages to most fossil-bearing strata. The absolute dates turned out to be entirely consistent with the relative dating done in the early 19th century. What does this result say about the assumptions behind relative dating?
[Hint]
To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
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| 4. |
Review the evidence for evolution analyzed in Sections 2.1-2.3. List the sources of evidence that were available to Darwin, and which appeared later. Indicate which evidence you consider strongest and weakest. Explain why.
[Hint]
To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
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| 5. |
Draw a simple phylogenetic tree showing what the relationships among five living species might be. Then, draw a genealogy of your family or a frirend's family, starting with the oldest and continuing to the youngest generation. Label the parts of each diagram. How are phylogenetic trees and pedigrees similar? How are they different?
[Hint]
To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
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| 6. |
According to the evolutionary tree shown in figure 2.10, are jaguarundis more closely related to tigers or to bobcats? Why?
[Hint]
To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
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| 7. |
Based on the assumption that extinctions were caused by catastrophic, worldwide floods of the type described in the Bible, what predictions does the Theory of Special Creation make about the nature of the fossil record? What predictions does the Theory of Evolution make about the nature of the fossil record?
[Hint]
To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
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| 8. |
The transitional fossils in Figure 2.7 demonstrate that dinosuars evolved feathers long before they evolved flight. Clearly, feathers did not evolve for their aerodynamic advantages. What else, besides aerodynamics, do feathers do for birds today? What advantages might feathers have offered for dinosaurs? Can you think of a way to test your hypotheses?
[Hint]
To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
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