Unit 3
Evolution and Behaviour

In this unit, we apply an evolutionary approach to studying animal (primate) behaviour. We explore the fundamentals of Darwinian natural selection as they apply to answering questions about ultimate (evolutionary) causes of behaviour, and how researchers approach questions of function using hypothesis testing and the scientific method. Unit 3 takes a more detailed look at levels of causation, and at the relative importance of genetic and environmental influences on behaviour. How do we know Darwinian logic applies to the study of behaviour? By exploring the concepts of group selection, kin selection, and reciprocal altruism we test alternative explanatory hypotheses vis-à-vis the Darwinian paradigm.

Objectives

When you have completed Unit 3, you should be able to

1. differentiate ultimate from proximate causes of behaviour, and explain how the scientific method is used to answer different levels of causation.
2. outline and explain the three basic tenets of Darwinian natural selection.
3. discuss the concepts of evolutionary costs and benefits in terms of reproductive fitness.
4. explain the concept of group selection and why it is problematic.
5. explain how we can understand different forms of altruism in light of evolutionary theory.

Viewing Assignments

In preparation for the first examination, you must watch at least three videos listed in Units 1 through 5. Each unit gives you two video options, so that by the end of Unit 5 you should have watched three videos from these four options:

Five Species or Primate Patterns II
Lemurs of Madagascar or Spirits of the Forest
Darwin’s Revolution in Thought or Great Transformations
Images from the Field or Baboon Tales

It does not matter the order in which you watch your video options, but the viewing assignments for each unit offer you a guide. Remember, completing a viewing assignment differs from watching a video for pleasure. You should consider watching each video twice: once to get an overview, and once to make notes. Study questions or instructions for viewing are supplied for each video; be certain that you read them over before you begin watching, and keep them in mind as you complete the assignment and make your notes.

Unit 3 Viewing Assignment

Choose one of the two video options below.

Gould, Stephen J.
1995  Darwin’s Revolution In Thought: An Illustrated
Lecture. Produced and directed by Robert DiNozzi. 50 min.
Into The Classroom Video. Northampton, MA.

This is a videotaped lecture by renowned Harvard professor and writer, Stephen J. Gould. In this lecture, Gould uses his storytelling powers to present three “riddles” about Darwin’s life and his theory of natural selection, and he uses each riddle to illustrate the philosophical implications of the theory that have been so controversial ever since Darwin. Gould is a very engaging speaker, and this video goes a long way to explaining the origins of Darwin’s theory and why we have such a hard time accepting it to this day. In particular, Gould points out that we have been unable to relinquish our belief that evolution is “progressive,” in that humans are somehow a destined outcome and end product of the process.

If you choose this video, then in preparation for the examination, be certain that you can answer the questions below.

1. Why was Charles Darwin aboard the H.M.S. Beagle?
2. What was the basis of William Paley’s so-called “argument from design” set out in his book, Natural Theology?
3. Why did Darwin wait so long after coming up with idea of natural selection before publishing On the Origin of Species in 1859?
4. How did Adam Smith’s prescriptions for a well ordered economy influence Darwin’s ideas about what happens in nature? In other words, how is laissez-faire capitalism analogous to natural selection?
5. What objections does Gould have to many modern depictions of evolution? Why, according to him, are these depictions inaccurate?

or

Olicker, Joel, and Chris Schmidt
2001.  Vol 2: Great Transformations. Joel Olicker, prod. and
dir. 57 min. In Evolution: A Journey into Where We’re From
and Where We’re Going. WGBH Educational Foundation
and Clear Blue Sky Productions, Inc.

This video looks at the mechanism behind evolution—how it works and how we know how it works. It explores the leaps in evolution as evidenced by the fossil record as well as the genetic mechanisms responsible for these leaps, some of them as dramatic as moving aquatic animals onto land, and others (as in the case of whale ancestors) transforming land animals back into sea creatures. Viewers are also presented with dramatizations of the painstaking processes and rewards of genetic research and discovery.

If you choose this video, then in preparation for the examination, be certain that you can answer the questions below.

1. What key aspect of aquatic mammal skeletal anatomy links them to land mammals?
2. What is the source of all evolutionary (genetic) novelty that creates the variation critical for natural selection to operate?
3. What are the HOX genes associated with?
4. In what way do HOX genes demonstrate that all organisms share a common ancestry?

Alternative Reading Assignment

If you cannot complete the viewing assignment before the midterm examination, you must do the alternative reading assignment instead. You may combine the reading with viewing assignments so that you have a total of three video and reading combinations. For example, you can watch two videos and do one reading assignment for the midterm. Or, if you cannot watch any videos, then you must complete three reading assignments from the four options presented in Units 1-5. The reading materials can be ordered from the library. Be sure you can answer the questions below each assignment.

Unit 3 Alternative Reading Assignment

If you cannot complete the viewing assignment for Unit 3, you must do the alternative assignment below.

Fedigan, Linda Marie
1992  Chapter Eighteen, Sociobiological Theories and Sex
Roles. In Primate Paradigms: Sex Roles and Social Bonds.
Pp. 287-306. Montreal: Eden Press.

In preparation for the examination, be sure that you can answer the questions given below.

1. What is the main tenet of sociobiology?
2. Outline Triver’s model of parental investment.
3. Why might some critics charge sociobiology with being a “sexist” theory?
4. What are the principal weaknesses of sociobiology?