ANSWERS to QUIZ 4 -- Brett's 730 PM THURS Section

1) What is the whole-organism approach? What are its main arguments regarding the role of genic selection (20pts)?

The whole-organism approach considers selection on the individual or less concisely: selection takes place on many phenotypic attributes simultaneously. The dichotomy between the whole-organism approach and genic selection appears to have roots in the 'How?' versus 'Why?' questions in evolutionary biology that were first discussed by Ernst Mayr. Recall from the first chapter on History and Method in Animal Behavior: Ultimate versus Proximate Mechanisms that I made a distinction between proximate mechanisms and ultimate mechanism. The concept of the gene as a unit of selection indentifies the gene as the source for all proximate mechanistic processes that lead up to the phenotype. It also identifies the gene as the key element in the selective processes that lead to evolution of the phenotype. In constrast, the whole-organism approach considers the atomization of phenotypic traits to the level of the gene unrealistic.

2) Discuss Tinbergen's method for the study of animal behavior. Give an example of the type of questions behavioral ecologists at each of the four levels (20pts).

Tinbergens 4 levels are as follows (supply any correct *specific example* -- many are possible)

  1. Causation refers to the proximate causes of behavior such as the hormones, genes, nerve impulses that control the expression of behaviors. E.g., haplodipoloidy as a control over sex determination in hymenoptera.
  2. Development refers to the ontogeny of behaviors such as imprinting, or in the case of cognition, issues of learning, which are all proximate mechanisms. E.g., learning of search image as a constraint on foraging on cryptic prey.
  3. Evolution refers to the phylogenetic context in which the behaviors are found. For example, the prevalence of parental care in birds, but not reptiles (with some exceptions) is an example of the taxonomic affiliations of some behaviors. This has to do with ultimate causes, for example, in the case of "phylogenetic constraints". E.g., constraints on neonate size in primates because of the pelvic girdle.
  4. Function refers to the adaptive value or contribution that the behavior makes to fitness. E.g.: selection on snake escape behavior or pattern.