1.
What is a fossil? Compare and contrast the four major types of fossils, with special attention to how the fossil is formed and the part(s) of the organism each preserves for study. In general, which are the most common, and why?
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2.
Describe the three types of bias in the fossil record and discuss the implications of these biases for our ability to gain useful information from the fossil record.
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3.
Describe the Ediacaran and Burgess Shale faunas and discuss their significance for our understanding of the events before and during the Cambrian.
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4.
Compare and contrast diploblastic vs. triploblastic; protostome vs. deuterostome; and lophotrochozoan vs. ecdysozoan. Which features preceded the Cambrian and which arose as part of the Cambrian "explosion"?
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5.
What do your textbook authors mean when they write that " ...the Cambrian explosion (may be) an explosion of animal morphologies, but not necessarily an explosion of lineages." What lines of evidence support this view?
[Hint ]
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6.
Describe the ecological differences apparent between the Ediacaran and Burgess Shale faunas. Discuss the possible roles of increasing oxygen levels and predation pressure in the evolution of larger, more complex bodies, mineralized shells, novel locomotor systems, and diversification of feeding ecology during the Cambrian explosion.
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7.
Define and give two examples of adaptive radiation. Describe the two key factors that seem to be involved in most adaptation radiations and give several examples of each.
[Hint ]
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8.
What is the predominant pattern of morphological change in the fossil record? Describe the theory of punctuated equilibria and explain (a) why it is difficult to test and (b) the conditions required for an acceptable test. What makes cheilostome bryozoans a good group for testing hypotheses about stasis? Discuss Cheetham et al.'s analysis of speciation and morphological change in this group, being sure to identify the specific prediction made by the hypothesis of punctuated equilibria.
[Hint ]
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9.
Is punctuated equilibria the rule, the exception, or something else? Explain. When stasis does occur, is there a single explanation that accounts for it? Why or why not? Defend your answer using Avise et al.'s studies of genetic variability in horseshoe crabs and Stanley and Yang's studies of morphological variation in bivalves to illustrate.
[Hint ]
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10.
What distinguishes mass extinctions from background extinctions? Approximately how many mass extinctions has the earth experienced and when did each occur? In general, how do rates of background extinction vary within and among clades? In general, how do rates of background extinction in marine organisms vary with the biology of the larval stage and with geographic range? Why does this relationship hold?
[Hint ]
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11.
What, in general terms, is the "impact hypothesis" for the end-Cretaceous (K-T) extinction? Discuss the evidence in favor of this hypothesis and describe the potential consequences of such an impact on biotic and abiotic systems. Did this extinction event affect all groups of organisms equally? Explain.
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12.
Discuss the evidence from Steadman et al.'s work on the Polynesian avifauna that humans have caused the extinction of 20% of bird species over the last 2000 years. Discuss the evidence suggesting that humans are currently causing extinction at a rate 100 to 1000 times the normal background rate, being sure to address any problems with the data and/or reasoning used to arrive at those rates. Where are current anthropogenic extinction threats most acute, and why?
[Hint ]
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