TASK 5

Question 1

Dominance hierarchies

Answer 1

• Some individuals are “higher” in rank than others and are constantly able to displace others from a resource
• dynamic ranking: can be challenged (by fighting) and reversed; higher ranks more stressed
• stable ranking: lower ranks more stressed

Question 2

Social-brain hypothesis idea

Answer 2

= Machiavellian intelligence hypothesis

• maintaining social relationships requires devoted brain mechanisms –> social species will have larger brains compared to non-social ones
• bigger brain size must have evolved as a result of bigger group size
• only focus on social knowledge

Question 3

Cultural intelligence hypothesis

Answer 3

• human’s unique cognitive skills is mainly due to species-specific set of social-cognitive skills for participating and exchanging knowledge in cultural groups
• humans only differ in cultural intelligence (proven in example with child and chimpanzee)
• can explain all knowledge (because it is derived from cultural intelligence)

Question 4

General Intelligence hypotheses

Answer 4

• larger brains enable more efficient use of all cognitive operations

Question 5

Adapted intelligence Hypothesis

Answer 5

• cognitive abilities evolve in response to relatively specific environmental challenges
• ecological theories and social theories combined

Question 6

Bottleneck effect

Answer 6

• Sharp reduction in the size of a population due to environmental events or human activities
• African bottleneck: 172,000 years ago
• -> small set of ancestors expanded out of Africa

Question 7

Allometry

Answer 7

= y = c * (w)^k

• Y (brain size) can be related to a more fundamental one W (body size)
• C and k are constants
• -> an increasing size does not have to result in an increase of its parts

Question 8

Encephalisation quotient (EQ)

Answer 8

= (actual brain weight)/(brain weight predicted from allometric line)
- departure of brain size from the allometric line

Question 9

Chihuahua fallacy

Answer 9

• Intelligence is too complex to have such a simple relationship
• small dogs (chihuahuas): body can be bred smaller but the brain size is less variable

Question 10

Basic metabolic rate (BMR)

Answer 10

• rate of energy expenditure per unit time by endothermic animals at rest
• Metabolism: comprises processes that the body needs to function

Question 11

Machiavellian intelligence hypothesis

Answer 11

• what differentiates primates from all other species was the complexity of their social lives and environment
• Machiavellian: misleading –> got replaced by the social brain hypothesis

Question 12

Apomorphies

Answer 12

• traits that are defining for all species afterwards
• a novel evolutionary trait that is unique to a particular species and all its descendants
• can be used as a defining character for a species/ group in phylogenetic terms

Question 13

Homology

Answer 13

similarity resulting from common ancestry (i.e. bones in hand and arm)

Question 14

Convergent evolution

Answer 14

gain of new, similar features independently (trait that develops independently)

Question 15

Pleistocene

Answer 15

• Ice Age = geological epoch that included the world’s most recent period of glaciations
  = ‘winter’

Question 16

Holocene

Answer 16

• Current geological epoch
• began after the last glacial period
  = warm period, ‘summer’

Question 17

Strepsirrhines

Answer 17

Suborder of primates that includes the lemuriform primates in Africa, Madagascar

Question 18

Haplorrhines

Answer 18

“dry-nosed” primates, suborder of primates containing the tarsiers as a sister of the strepsirrhines

Question 19

Prosimians

Answer 19

Group of primates that includes all living and extinct strepsirrhines and haplorrhines

Question 20

Platyrrhines

Answer 20

• Group of primates that includes the new-world apes, marmosets and tamarins
• distinguished by having nostrils that are far apart and directed forwards or sideways and typically have a tail

Question 21

Catarrhines

Answer 21

• Group of primates that include the old-world apes

- characterised by having nostrils close together with an opening in front of the face

Question 22

Brachiation

Answer 22

mode of locomotion involving swinging from branch to branch using only arms

Question 23

Hominins

Answer 23

• intermediate forms between chimpanzees and the humans today
• not a single evolving lineage –> branching of multiple forms, many of which go extinct and only some of which are on the line leading to living humans

Question 24

Out-of-Africa model

Answer 24

• AMH is a new species that replaced the other living hominins without interbreeding
• Morphology: universal similarity; not Asians resemble Erectus more etc.
• Genetic evidence: deep branches between contemporary Africans
• -> African bottleneck: small set of ancestors expanded out of Africa
• Neanderthal DNA

Question 25

Ecological intelligence hypothesis

Answer 25

• cognitive skills evolved mainly in response to the especially challenging demands of foraging for seasonal fruits and resources embedded in substrates

Question 26

Expensive tissue hypothesis

Answer 26

• increases in brain size fmust have been balanced by a reduction of demands of other organs (gut reduction)
• Carnivores need to kill (requires speed, strength & adequate perception to catch the prey) –> hunting & gathering intellectually demanding –> larger brain

Question 27

Arboreal theory

Answer 27

• moving & feeding on land required stereoscopic vision and dextrous hands –> both of required a large brain to coordinate and control

Question 28

Fruit hypothesis (Diet hypothesis)

Answer 28

• leaves are harder to digest
• -> Fruit: lots of calories in easy to digest package (no thick cell walls)
• Diet & sociality as complementary explanations

Question 29

What makes us human?

Answer 29

• Bipedialism: walking on 2 feet
• Meat eating
• Tool use
• Brain size
• Life history
• Learning niche
• Language
• Ballistics: enhanced lateralisation of the brain

Question 30

Meat eating

Answer 30

• high-quality resource used to fund metabolic cost of large brains
• guts became smaller (meat is easier to digest) –> freed up energy for brain

Question 31

Tool use

Answer 31

• not restricted to humans –> humans greater dependency + more sophisticated use
• appearance of new tools not well correlated with anatomical changes

Question 32

Brain size

Answer 32

• larger brains relative to chimpanzees (not accounted for by larger body size)
• -> Allometry (positive EQ)

Question 33

Life history

Answer 33

• lifespan and period of development have increased/ elongated
• born rather undeveloped (head otherwise too big for birth) –> fast post-natal developments
• outweigh cost of investment in development –> live longer
• family structure follows extended developmental period –> relatives help out

Question 34

Learning niche

Answer 34

• high-skill foraging makes humans able to occupy very different environments in many ingenious ways
• need more time to learn skills –> chance of inventing things
• Long period of childhood: enables communication between preformed brain modules –> allows cognitive fluidity

Question 35

Language

Answer 35

• productive language: produce nearly everything with different parts (words to produce sentences)
• refer to things that aren’t present –> increased efficiency of social learning
• gossip & the maintenance of cooperation by indirect reciprocity
• FOXP2 mutation

Question 36

Australopithecines

Answer 36

• 4 million - 1 million years ago
• climate change: drying of climate, fragmenting of forest –> increased fitness of bipedalism
• size of chimpanzees
• mostly depends on plants
• robust: more robust teeth/jaws
• gracile: evolved into Homo

Question 37

Early Homo

Answer 37

• 2,5 million years ago
• brain size begins to clearly move toward human pattern
• stone tools
• full bipedalism & long-range mobility in place –> wander from Africa to Asia
• began to depend on meat
• -> Homo habilis
• -> Homo erectus: Asia
• Homo floresiensis: island; dwarf human

Question 38

Archaics

Answer 38

• 0,8 million years ago
• expanded size of body & brain, more complex tools
• Homo neanderthalensis: Europe;

Question 39

Homo sapiens

Answer 39

= AMH (anatomical modern human)

- Bottleneck effect: expansion & divergence began with small population in Africa

Question 40

ARGHAGAP11B gene

Answer 40

• drives the expansion of the human brain

- needs other genes to make those neurones form functional networks in brain