Unit 2 - Lecture - Part One - Primate Behavior and Hominin Models

Functional Morphology

The study of how an organism's structure (anatomy) relates to its function, exploring how biological form is shaped by evolutionary adaptations to optimize specific tasks and behaviors

Socioecology

The relationship between organismal behavior and all aspects of their environment other than their immediate social environment

Sociobiology

The systematic study of the biological basis of social behavior, examining how natural selection shapes behaviors like altruism, aggression, and mating patterns in all organisms, including humans

How do human’s brain size and shape differ them from other hominoids?

• Larger

• Left/Right symmetry

• Modularity

• Broca’s and Wernick's Area

• Facial reduction and retration

  • Dental Reduction

  • Loss of canine sectorial complex

How do humans differ behaviorally than that of other hominids?

• Permanent male-female bonded social units

• Tool-use dependency (extrasomatic adaptation)

• Male-Female division of labor

  • Hunting vs Foraging

• Base camps and food sharing

• Symbolic cognition

• Culture

Symbolic Cognition

Theory of mind, imagined worlds, art, body adornments, and language

Single Male (Harem) Groups

• Single adult male

• Several adult females and offspring

• Females usually related

• females are permanent nucleus of group

• High sexual dimorphism/small testes

Multimale-Multifemale Groups

• Several adult males, females, and offspring

• Several males reproduce

• Male and female dominance hierarchies

• High-medium sexual dimorphism

• Sperm competition/large testes

Monogamous Pair Bonding

• Mated male-female pair and offspring

• Usually arboreal

• Territorial

• Sexual Dimorphism: Minimal to none

• Among the LEAST COMMON primate group structures

Polyandry

• One female and two males

• Relatively rare (only some NWM)

Solitary/semi-solitary

• Adult one male(s)

What is Altruism?

Behavior that benefits another individual at some potential risk or cost to oneself

What is Game Theory?

Mathematical models of strategic interaction among rational decision-makers

• Predicted that the evolution of “cheating” should always undercut altruism

Who discovered that the apparent perception of altruism was not true in the case of tropical songbirds due to the temperate breeders having longer days in which to find food than tropical breeders, hence laying less eggs.

David Lack

How has the evolution of human social structure evolved?

Wider cultural transmission in humans, due to much wider, complex social networks of groups in which many of the individuals in the groups are not closely related