Wilson Study Guide II: Parts III and IV (Chapters 12 – 19) Wilson now switches to his own research specialty – ants! What he will do first is describe the amazing social structures found in various kinds of ants and termites based on fieldwork. Here is speaks with great authority. Next he describes various behaviors that contribute to these social structures and places them in the order in which they seem likely to have evolved. So, for example, nest building probably preceded division of labor. As far as I can tell, this ordering is not controversial. However, we need to remember that tracing steps in evolution is not easy, even in the case of the appearance of four-legs. (See quotation below.) Wilson then turns to the issue where he disagrees with many of his colleagues: What sort of selection process was at work in each of these steps? Specifically, does kin selection provide a good explanation of eusociality? It is here that his argument becomes difficult to follow. We’ll work on it in class! 1. p. 120: He writes: “Then they hit upon innovations…parallel to human … inventions.” Translate the phrase “hit upon innovations” into more orthodox Darwinian terms. Are they still parallel to human inventions? 2. p. 137: Possible oral report topics: Eusociality in naked mole rats or Synalpheus shrimps. 3. p. 143: Here he alludes to the controversy but doesn’t explain it in detail. 4. Chapters 16 and 17 are comparatively straightforward. Look up any terms where you feel the need for clarification, e.g., “phenotypic plasticity.” 5. Chapter 18 describes the controversy. I suggest you read clear through it, trying not to get too bogged down or discouraged. And then go back and read carefully the example of the birds hanging around the nest on pages 179-80. Here he clearly contrasts a kin- selection explanation vs. an alternative “floating strategy” account. How might a “floating strategy” evolve? What kinds of empirical data could decide which account is correct? 6. Chapter 19 presents a theory of how eusocial insects might have evolved. Note that no one in the controversy disputes that certain insects are eusocial, nor that these behaviors evolved through natural selection. The dispute is about the roles of kin selection vs. group selection and superorganisms. We may wonder why we, the general public should care about a seemingly abstruse debate. The next unit will shed some light on that. *********************************************************************

“Experts differ about the environmental pressures that prompted lobe-finned fish to evolve into walking, breathing tetrapods. One theory is that the shallow lakes and rivers these fish lived in were subject to drought, favoring species that could survive (at least for a while) in dry conditions. Another theory has it that the earliest tetrapods were literally chased out of the water by bigger fish: dry land harbored an abundance of insect and plant food, and a marked absence of dangerous predators. Any lobe-finned fish that blundered onto land would have found itself in (by Devonian terms, at least) a veritable paradise.” http://dinosaurs.about.com/od/otherprehistoriclife/a/tetrapods.htm