W3 L2 Brain size and intelligent Th

Question 1

Differences between us and other primate aka chimp

Answer 1

-genetically, very little: 1%
-Strong social behavior
-Unusual kinship, parenting and grandparent. Teaching
-Unusual life histories
Unique physical feature

Question 2

What is a genetic species definition

Answer 2

-group of genetically compatible interbreeding natural populations that is genetically isolated from other such groups. Focus more on genetic isolation

Question 3

Mammal brains

Answer 3

Generally, larger mammals have larger brains, but this doesn’t necessarily equate to intelligencE
-human have the largest relative brain size

Question 4

Increase in human brain size through time

Answer 4

-bipedal manual dexterity, tool use and meat consumption lead to selection for larger brain

Question 5

Is diet linked to brain size

Answer 5

• Leonard et al. (2003), examined brain size and diet quality in 41 primate species
• Diet quality assessed by looking at % of plants, fruits and animals in diet
• Higher score given to animal > fruits > plants
  -there is a trend that meat eater have larger brain
  -human is still outlier

Question 6

The metabolic cost of large brains

Answer 6

• Brain tissue is the most energetically expensive tissue ( ≈ 16x more energy consuming than muscle)
• Human brain = 2% of body mass
  (20-25% of our energetic demands)
• Other primates = 8-10% of energetic demands
  -but we are metabolically average, possible trading with other tissue demand

Question 7

Human guts expected and observation

Answer 7

-human have a bigger porpotion of brain weight than expected and smaller guts
-predicted brain size is 268g but irl is 1.3kg

Question 8

A. Afarensis the first family

Answer 8

Discovered in 1975 in Ethiopia 3.2 Mya
-17 individual 9Adult, 3 adolescents and 5 children
- all killed together, cause unknow

Question 9

The “Social Brain” Hypothesis

Answer 9

Living in large groups imposes large cognitive demands
-better ability to process social information
-predict other behavior
- ability to manipulate other

Question 10

What parts of the brain are important

Answer 10

The neocortex is the most important for explaining large brain size in humans and other primates
-human have a larger a neocortex ratio for it’s group size

Question 11

What is social intelligence

Answer 11

-believe to be the ability to learn from social situation.
-the executive brain ration is positively related to social learning frequency
-but to relationship between group size and social learning so no causal link for now

Question 12

Why do we have small canines

Answer 12

• Primates with smaller canines tend to have wider faces
• In humans, men have wider faces than women
• Women prefer men with wide faces (and prominent cheeks), this is also a sign of less aggression
• Sexual selection against long canines