Unit 2
Introduction to the Order Primates

In this unit, we investigate the living primates. Further, we explore the evolutionary, morphological, and behavioural characteristics that distinguish the order Primates (to which humans also belong) from other mammalian orders. Before considering the diversity of primate behaviours in detail, we survey the taxonomic groups of primates, their distinguishing features, and their geographical distributions. We examine the “primate pattern,” which outlines the adaptive suite of traits that characterize primates, and by extension, gives us insight into their evolutionary past. Unit 2 also applies a phylogenetic (evolutionary) analysis to behaviour, and explores how we can reconstruct evolutionary trends in morphology and in behavioural ecology.

Objectives

When you have completed Unit 2, you should be able to

1. identify the four major categories of traits that distinguish primates from other animals.
2. explain the relationship between brain size and body size that is characteristic of primates.
3. identify the major taxonomic groups within the order Primates (Prosimii and Anthropoidea) and categorize the major groups within each category (lemurs, lorises, tarsiers, platyrrhines, and catarrhines) based on their morphological features.
4. explain how the morphology and anatomy of primates is the result of adaptations to the environment, and discuss the evolutionary significance of key primate adaptations.
5. provide examples of the variation in morphology and anatomy found in the order Primates.
6. compare “primitive” and “derived” traits, “homology” and “analogy,” and convergent and parallel evolution.
7. explain how phylogenetic analyses are applied to behaviour.

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 2 Viewing Assignment

Watch one of the two videos below.

Zeller, Anne
1997  Lemurs of Madagascar. Watertown, MA: Documentary
Educational Resources.

This video provides a detailed description and comparison of nine species of prosimians. Detailed descriptions of the habitat and behaviours are presented to provide an idea of the range of adaptations and diversity of behaviours across the Suborder Prosimii. The video compares the same type of behaviours seen in the two previous videos, but with a greater emphasis on habitats.

In the examination, you will be asked to give brief descriptions of the characteristics of two of these species (i.e., diet, habitats, locomotion, sexual dimorphism, vocalizations, physical descriptions, weaning behaviours, grooming, and male-female interactions). Pay attention to the functions of some of the behaviours described as well.

or

Time Life
1989  Spirits of the Forest. New York: Time Life Video.

This video describes the general features of the social organization and habitats of several lemur species, with a focus on the ringtailed lemur and the sifaka.

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

1. What types of social groups do each of the species presented typically form?
2. Where are the scent glands located, and for what are they used?
3. How do females carry their infants?
4. What is the dominance structure among the ringtailed lemurs?
5. Why are sifakas able to live in very dry areas?
6. What are the general differences between these species?
7. What are stink fights?

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 2 Alternative Reading Assignment

If you cannot complete the viewing assignment, do the alternative reading assignment below.

Rodman, Peter, and John Mitani
1987  Orangutans: Sexual Dimorphism in a Solitary Species.
In Primate Societies. B. Smuts, D. Cheney, R. Seyfarth,
R. Wrangham and T. Struhsaker, eds. Pp. 146-154.
Chicago: University of Chicago Press.

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

1. What forms of locomotion do orangutans use?
2. What is their typical diet?
3. What are the three primary social units of orangutans?
4. How can differences in body size between males be explained?
5. How is sexual dimorphism in body size related to differences in diet?
6. How does sexual dimorphism influence locomotion?
7. What is the function of cheek pads in males?