Refining the Hominid ModelRefining the Hominid Model

Behavioral EcologyBehavioral Ecology

Summary of LovejoySummary of Lovejoy’’s Premises:s Premises:

1.1. Bipedalism Bipedalism is inefficient for locomotionis inefficient for locomotion2. 2. Bipedalism Bipedalism is a reproductive strategyis a reproductive strategy3. Earliest australopithecines developed the 3. Earliest australopithecines developed the

major hominid behavioral traits all at oncemajor hominid behavioral traits all at once–– Food exchangeFood exchange–– MonogamyMonogamy–– Home baseHome base

4. Environment and diet were not key factors4. Environment and diet were not key factors

The Nineties: New DirectionsThe Nineties: New DirectionsLovejoyLovejoy’’s hypothesis sets the standard in late 70s hypothesis sets the standard in late 70’’ss–– Complex functional relationshipsComplex functional relationships–– Attention to whole adaptive pictureAttention to whole adaptive picture–– Life history analysisLife history analysis

Growth of scientific rigorGrowth of scientific rigor–– The The ““NewNew”” Archeology Archeology

»» Rigorous testing of competing hypothesesRigorous testing of competing hypotheses

–– Biology: Behavioral EcologyBiology: Behavioral Ecology»» Competing modelsCompeting models»» Integration of Integration of primatologyprimatology, ethnology, , ethnology,

physiology, life history, ecology, etc.physiology, life history, ecology, etc.»» QuantificationQuantification»» Prediction and testingPrediction and testing Lew Binford

ChallengesChallenges to Lovejoyto Lovejoy’’s Premisess Premises

1.1. Bipedalism Bipedalism is inefficient for locomotionis inefficient for locomotion2. 2. Bipedalism Bipedalism is a reproductive strategyis a reproductive strategy3. Earliest australopithecines developed all the 3. Earliest australopithecines developed all the

major hominid behavioral traitsmajor hominid behavioral traits–– Food exchangeFood exchange–– MonogamyMonogamy–– Home baseHome base

4. Environment not a key factor in this shift4. Environment not a key factor in this shift

Bipedalism Bipedalism reconsidered: thereconsidered: theRodmanRodman--McHenry HypothesisMcHenry Hypothesis

Bipedalism Bipedalism NOT NOT Inefficient!Inefficient!Efficient for open Efficient for open countrycountryEcology, climate, Ecology, climate, feeding patternsfeeding patternsEast African East African geographygeography……

WolpoffWolpoff,, PaleoanthropologyPaleoanthropology

Global coolingGlobal coolingLifting and riftingLifting and rifting–– Rain magnets & Rain magnets &

shadowsshadows–– Lakes & Lakes &

riversrivers

VolcanismVolcanismLocally rich Locally rich grassland habitatsgrassland habitats““East Side StoryEast Side Story””––hominidhominidspeciationspeciationEast Africa today...East Africa today...

East Africa: Mosaic EnvironmentEast Africa: Mosaic Environment

East Africa, 1999East Africa, 1999East Africa

ACMACM19991999

Role of ElevationRole of Elevation

Biosystem Biosystem DiversityDiversity

Savannah GrasslandsSavannah Grasslands

Open WoodlandsOpen Woodlands

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