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Lecture Notes
Chapter 3

• Intelligence testing
• Hereditary Genius (1869)
• Twins
• Nature vs. nurture

• Nature and nurture

Francis Bacon (1561-1626)

• Novum organum (1620); variation across generations

• Ammonites and nautilus; environment causes change

• Adaptation to fit environment (e.g., suggested North American bison derived from ox)

• The Botanic Garden

• Individuals change during lifetime
• Changes passed to offspring

• "If these modifications lead to injurious effects, the animals which exhibit them perish and are replaced by others of a somewhat different form, a form changed so as to be adapted to the new environment."
• But...some weird ideas; tarnished Lamarckian evolution

HMS Beagle (1831-1836)

1837, started notebook on "transformation of species"...ideas mostly complete by 1839

• Read Malthus' Essay on the Principle of Population; not everyone can survive

Adaptation; "blind chance"

Evolution as adaptation

 
Charles Darwin (left) and Alfred Wallace (right) (figs from Futuyama, 1986, p. 5)

Detail of chromosomes

• What genes you have
• Your potential

• The genes you manifest
• Your appearance
• Environmental interaction

• Identical twins
• Fertilized egg cleaves apart
• Genotype identical
• Phenotype different

• Fraternal twins
• Two eggs fertilized by two sperm
• Genotype different
• Phenotype different

Clones

• Precise replication

  

  
Mitosis in root tip cells of Lilium regale (Suzuki et al., 1986, p. 35)

• 23 chromosomes; 200,000 genes

• 1 in 100,000 chance

"Infinite" possibilities

(From: Gonick and Wheelis, 1991, p. 80)

Mutations

• No effect
• Fatal
• Beneficial

• "Fatal, but not serious."

• Gene site; alleles

Heterozygous

Dominant gene

Recessive gene

Both chromosome copies in sperm/egg

Piece of chromosome lost

Usually non-viable zygote results

Male:XY

Survivable errors:

• XXX...female
• XYY...male
• X0...female (Turner's syndrome)
• XXY...male (Klinefelter's syndrome)

Evolutionary mechanisms

Social behaviours

E.O. Wilson

• Holding and maintaining territory

Bobcat methods of maintaining territory and driving off intruders. From: Macdonald (1984), p. 54

Dominance

• Establishing a hierarchy

Wolves determining social hierarchy, from Macdonald (1984), p. 59

Sexual

• Males threatening or attacking females for the sole purpose of mating.

  
Lions mating, from Macdonald (1984), p. 31.

Others

• Parenting discipline
• Weaning
• Predatory
• Anti-predatory
• Moralistic

Adaptive

e.g., Polyergus breviceps

Polyergus breviceps attacking, from: Hölldobler and Wilson (1990)

• Male-male, infanticide

• Mothers must guard cubs

 
Male lion with killed cub (left) and hyenas feeding (right). From: Macdonald (1984), p. 35 and 154

Attacks with intent to kill will produce all-out defenses

Increased aggressive behaviour means less time for everything else

Genetic

• High degree of heritability
• Fixed action patterns

Food

Crowding

Mating season

 
Foraging baboon (left) and Sifaka lemur (right). From: Macdonald (1984), p. 371 and 329

Win/lose experience shapes behaviour

Rearing conditions

Innate ability and environmental factors

Aggression not a neurosis

Overcrowding

• e.g., studies by Leyhausen (1965), Calhoun (1962)

• William D. Hamilton (1964, 1970)

Shared genetic material between related animals

Coefficient of relationship, r

• Siblings, r=0.5; uncle, r=0.25; first cousins, r=0.125

Selfishness

Spite

Why not cheat?

• Societal knowledge

Few animal examples

• Monkeys, apes, wolves, African wild dogs

African wild dog, from: Macdonald (1984), p. 76

Cooperative breeding

Food sharing

 
Musk oxen (left) and Naked mole rats, the only true eusocial mammal (right). From: Macdonald (1984), p. 5 and 711