Transcript Lecture 2 - Organic Origins Debate

The Problem of Survival
Human Life and All Things
Nasty, Brutish, and Short
Universality of Human Nature
Humans, as a species, faced common
problems
 The adaptive solutions to these problems
form the basic structure of human nature
 These adaptations are considered human
“universals”

Major Survival Problems
Food acquisition & selection
 Habitat
 Environmental threats
 Senescence

Food Acquisition & Selection




We need food to supply energy, but not all
organisms “want” to be eaten
Food aversions
Food sharing serves both survival and
reproductive (i.e., courtship) ends
Pregnancy sickness:
 Teratogens
 Dangers of not experiencing pregnancy
sickness
Hunting



Humans consume large amount of meat,
compared to other primates
Provisioning explains high male parental
investment & sexual division of labour
 However, egalitarian food sharing
“Showoffs” get sexual access & other benefits
in exchange for meat
Gathering
Meat still constitutes low proportion of diet
 Gathered plants constitute 50-80% of
modern hunter-gatherer diets
 Tools used in gathering
 Puts evolutionary emphasis on women
 Adjust their foraging to husband’s hunting
success

Hunting vs. Gathering


Gathering:
 Doesn’t explain hominid divergence
 Doesn’t explain division of labour
 Men “parasitising” women’s labours
Hunting:
 Small, but consistent, proportion of diet
 Explains above problems
Scavenging



Proportion of meat acquired through
scavenging
Stone tools used (cut marks)
Problems:
 Range too great to find regular kills
 Left-over meat from kill?
 Competition with other species
 Rotting
The Savanna Hypothesis
Natural landscape preferences
 Habitat selection:

Selection
 Information gathering
 Exploitation


Flowers & the onset of edible foods
Environmental Threats
Predators & Poisons:
 Fear of snakes, spiders, blood
 Adaptations: freeze, avoid/escape,
defense, appeasement
 Physical environment:
 Heights, disease, strangers
 “Preparedness”

Senescence
“Aging” is an ambiguous term
 We are not like washing machines that break
apart after long-term use
 Senescence is the continuous deterioration
over our bodily mechanisms
 Selection operates most greatly on organisms
at time of peak reproductive value
 Suicide & reproductive value

The Wrap-Up
Universality of Human Nature
 Survival problems:
 Food
 Habitat
 Environmental threats
 Senescence

Things to Come




The Evolution of Sex
 Asexual vs. sexual reproduction
 Genetic copying errors
 Parasite defense
Sex Ratios
Minimum Investment
Sexual Dimorphism