Gould, S. J. and Lewontin, R. C. 1979. The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist programme. Proc. R. Soc. Lond. B 205:581-598.

1. What is this adaptationist program that so concerns Gould and Lewontin? In what sense is it a program? Why do they believe it is problematic?
2. Are Gould and Lewontin arguing against the reality of adaptation?
3. Construct an adaptive explanation for the following traits: white bark in birch trees, thick bark in oaks, white fur in polar bears, philandering by men, racism, homosexual behavior, homophobia, the red color of blood.
4. That was easy, wasn't it? Gould and Lewontin seem especially bothered by the ease with which we construct adaptive explanations for traits, and our ability to "concoct" a new adaptive story if our original one fails. What is the problem with this?
5. Provide an example of a plant or animal trait (not cited in this paper) which may have arisen as a by-product of selection for another trait.
6. In Section 5 (p. 156) Gould and Lewontin say that "at present population geneticists are sharply divided on the question of how much genetic polymorphism within populations and how much of the genetic differences between species is, in fact, the result of natural selection as opposed to purely random factors." This was written in 1979. What do we know about this today?
7. Discuss some alternatives to adaptationist reasoning, citing examples not mentioned in this paper.

No specific questions -- but this paper provides a useful overview of the Gould and Lewontin paper in the light of current research in genetics, evolution and adaptation. Pigliucci and Kaplan suggest that the political views of Gould and Lewontin influenced their decision to write the Spandrels paper. What do you think?

Elle, E. et al. 1999. Cost of glandular trichomes, a "resistance" character in Datura wrightii Regel (Solanaceae). Evolution 53:22-35.

1. What was the main hypothesis tested by this investigation?
2. Explain how the genetic basis of trichome morphology in this species makes it an ideal subject for investigation of the costs of herbivore resistance.
3. Explain how the experiments were designed to test the hypothesis. Specifically …

• How was herbivory controlled?
• How was the effect of herbivory measured?
• How were interactions between experimental factors incorporated into the design?
• How was the cost of resistance measured?

1. Be prepared to discuss Table 2, especially as it relates to interaction. Some hints: in Table 2a, an F of 235.06 with a P of .0001 for "Herbivory" indicates that the mean mortality rates for plants exposed to herbivores and those excluded from herbivores were significantly different. This is a main effect. For "Type X Herbivory" the values of F and P are 9.60 and .0030, respectively. This means that the effect of herbivory on mortality differed significantly between the two plant types. This is an interaction effect. P values > .05 imply no significant effect.
2. Is there an apparent cost to producing sticky trichomes?
3. Is there a net benefit to producing sticky trichomes which compensates for this cost? If not, why do the plants go to the trouble? Relate this situation to the Gould and Lewontin paper.

1. Show and tell: Find (in a textbook) an illustration or account of the giraffe's neck as explained on Darwinian lines (feeding competition) as opposed to Lamarckian lines (inheritance of acquired characteristics). Bring the book or a copy of the relevant pages to class.
2. Explain the feeding competition hypothesis for long giraffe necks. What evidence should be brought to bear on this hypothesis? What light does the evidence shed on the hypothesis?
3. Explain the sexual selection hypothesis for long giraffe necks. What evidence should be brought to bear on this hypothesis? What light does the evidence shed on the hypothesis?
4. Why do Simmons and Scheepers discuss scaling relationships (isometry, allometry), for example comparing giraffe and okapi, male and female giraffe?
5. Be prepared to discuss Figure 1.
6. Sexual selection may explain why male giraffe have long necks, but why should females have long necks?
7. Describe some of the fitness costs of long necks resulting from sexual selection.
8. For teachers: how will you deal with all this?