Social Structure: stability/instability - PowerPoint PPT Presentation

Social structure stability instability l.jpg
1 / 15

  • Uploaded on
  • Presentation posted in: Pets / Animals

Social Structure: stability/instability. WFSC 422 Ethology Presentation 6.1. Dr. Jane M. Packard, WFSC TAMU Territories vs. dominance. Territories Intense combat between SEVERAL groups defense of space- group home range group access to resources Dominance

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Download Presentation

Social Structure: stability/instability

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

Social structure stability instability l.jpg

Social Structure: stability/instability

WFSC 422 Ethology

Presentation 6.1

Dr. Jane M. Packard, WFSC TAMU

Territories vs dominance l.jpg

Territories vs. dominance

  • Territories

    • Intense combat between SEVERAL groups

    • defense of space- group home range

    • group access to resources

  • Dominance

    • Minor conflict among individuals in ONE group

    • defense of personal distance

    • individual access to resources

Example trumpeter swans l.jpg

Example: trumpeter swans

Swans in group out group l.jpg

Swans- “in group” “out group”

  • In group- stable hierarchy

    • family- parents & offspring

    • no turnover in membership

    • each learns what to expect from others

  • Out group- contest of strength

    • family groups gather on lake during migration

    • contests between families over resources

    • bigger, stronger families win over singles & smaller families

Social structure 3 hypotheses l.jpg

Social Structure- 3 hypotheses

  • In stable groups, conflict is predictable

    • e.g. pecking order in chickens

  • In unstable groups, conflict depends on friends & rivals

    • e.g. appeasement & grooming in baboons

  • In social insects, castes are fixed (nutrition)

    • no conflict e.g. Leaf cutter ants

Example chickens l.jpg

Example- chickens

Stable chicken peck order l.jpg

Stable- chicken “peck order”

  • Alpha- 1 hen pecks all others

  • beta- “second in command”

    • pecked by alpha

    • pecks all others

  • omega- “bottom of hierarchy”

    • pecked by all others

    • does not peck back

  • stability depends on order of entry into group- younger new ones are pecked

Unstable baboons open group l.jpg

Unstable- baboons (open group)

Example baboon appeasement l.jpg

Example- baboon appeasement

Baboons age affects stability l.jpg

Baboons- age affects stability

  • Females

    • youngest daughter supported by mother

    • older daughters drop in rank

  • males

    • leave mother’s group, enter a new group

    • form alliance with females, appease males

    • rise in rank as older males weaken or die

Example fixed instinct l.jpg

Example- fixed instinct

Stable castes leaf cutter ants l.jpg

Stable castes- leaf cutter ants

Ant castes hard wired roles l.jpg

Ant castes- “hard wired roles”

  • Diploid (fertilized)- females

    • largest- reproductive queen

    • large- soldiers

    • small- workers (brood care, foragers)

    • dependent on nutrition at a critical stage of development

  • haploid (unfertilized)- males

    • produced near the end of queen’s life

    • mate (3-4 with one queen), then die

Summary l.jpg


  • Distinguish between out-group intense combat (e.g. defense of territory) and in-group mild conflict (e.g. hierarchy)

  • 3 hypotheses of social structure

    • Stable groups => predictable conflict

    • Unstable groups=> friends & rivals change

    • Social insects=> castes fixed by nutrition

Action items l.jpg

Action Items

  • Do answers for Q6.1, Q6.2

  • Search idealibrary for “social structure”

  • Search Animal Behavior for “dominance”, “hierarchy”

  • Post examples and sources on WebCT Discussion for Unit 6

  • Login