Psychology 351 – Animal Behavior

Alcock, Chapter 1 - An Evolutionary Approach to Animal Behavior
Summary by Kris Mattox.

Understanding Monogamy
- Monogamous : One sexual partner (example – prairie vole)
  • Able to be more reproductive with (1) partner because they can keep their partners from copulating with other males (have more descendants of their species).
  • In nature, males that left their mates might lose them to other males, which would translate into reduced paternity for the less monogamous males.
- Polygynous : Several sexual partners (example – most other mammals)

Levels of Analysis
- Proximate Causes : Immediate causes (answers how animals behave the way they do)
  1. Genetic – Developmental mechanisms, such as the effects of hereditary on behavior and the development of sensory-motor systems via gene-environment interactions.
  2. Sensory – Motor mechanisms, such as nervous systems for the detection of environmental stimuli, hormone systems for adjusting responsiveness to environmental stimuli, and skeletal-muscular systems for carrying out responses.
- Ultimate Causes : Evolutionary causes (answers why animals behave the way they do)
  1. Historical pathways leading to a current behavioral trait. Events occurring over evolution from the origin of the trait to the present.
  2. Selective processes shaping the history of a behavioral trait. Past and current usefulness of the behavior in promoting lifetime reproductive success.

How to Discover the Causes of Behavior – Scientifically
- Hypothesis : educated guess.
  • Example – A receptor difference between voles suggested a possible explanation for the behavioral difference between the two kinds of voles, a working hypothesis that required verification before it could be accepted.
- If-Then Logic : if the vasopressin receptor explanation is correct, then a given experiment should generate specific results.

Darwinian Theory and Ultimate Hypotheses
- Darwinian Theory is based on the premise that evolutionary change is inevitable when (3) conditions are met.
  1. Variation - such that members of a species differ in some of their characteristics.
  2. Hereditary - with parents able to pass on some of their distinctive characteristics to their offspring.
  3. Differences in Reproductive Success - such that some individuals have more surviving offspring than others in their population, thanks to their distinctive characteristics.
- Natural Selection : the process that causes evolutionary change (according to Darwin)
- Genes : the segments of DNA that faithfully encode the information needed for the synthesis (production) of proteins.
- Alleles : when a given gene exists in (2) or more forms within a species’ gene pool.

The Problem with Group Selection
- Group Selection : based on differences among groups in their ability to survive.
      • Example** – the survival of alternative alleles was much more likely to determined by differences in the reproductive success of genetically different individuals (natural selection) than by survival differences among genetically different groups (group selection).