evolution

Question 1

what did Darwin notice in the Galapagos islands (Ecuador)?

Answer 1

Darwin visits in 1935

geologically young island with high number of endemic species

notices that mockingbirds differed between islands

takes back samples of mockingbirds and finches for further study

Question 2

what are endemic species?

Answer 2

large number of species native to a large area/region

evolve in isolation so unique to environment

found usually in remote islands/ecosystems

Question 3

what is functionalism?

Answer 3

characteristics of an organism has a useful function - all for survival

to understand physiological basis of various behaviours (how) we must first understand what these behaviours accomplish (why)

Question 4

what are the mechanisms of natural selection?

Answer 4

differences are seen within species and inherited by offspring

favourable characteristics that have help in survival and reproduction get passed onto offspring

over generations, these characteristics become dominant

mutations (accidental errors) can occur

drives adaptive radiation

Question 5

what happens when mutations (accidental errors) occur?

Answer 5

non-useful die out

favourable passed onto offspring

Question 6

what is adaptive radiation?

Answer 6

single species rapidly evolves into multiple new species to match survival

little competition and diverse resources

Question 7

what happened with Darwin’s finches?

Answer 7

common ancestor first arrives

different islands have different resources

natural selection - beak shapes to food source

over time, multiple new species evolved

Question 8

what is a brief history of human evolution?

Answer 8

earliest mammals - small nocturnal predators that fed on instincts

first hominids (humanlike apes) appeared in Africa

first hominid to leave Africa around 1.7 million years ago

human evolution was relatively late development - given overall timescale of primate evolution (some 60 million years ago)

rapid evolution of human brain and behaviour sets us apart but also seen as part of the evidence for our animal ancestry

Question 9

what are the existing relatives of humans?

Answer 9

our closest living relatives - chimpanzees, gorillas, orangutans

DNA analysis - very little difference between these four species

Question 10

does a large body equal a large brain?

Answer 10

elephant brain = 0.2% of its total body weight

human brain = 2.3%

shrew = 3.3%

Question 11

does size matter?

Answer 11

neurons and complexity are key

human useful functions and need for complex brain (bipedalism, opposable thumbs, colour vision, linguistic abilities)

climate change and habitat shift = seen in drier lands so can go farther in search of food and water so needed to be efficient

better thermoregulation = larger body surface area for exposure to direct sunlike

improved vision = better vantage point to spot food or predators

Question 12

what is bipedalism useful for?

Answer 12

mobility

energy efficiency

adaptibility

Question 13

what are opposable thumbs useful for?

Answer 13

agile hands for tool use

Question 14

what is colour vision useful for?

Answer 14

differentiate fruits from leaves

fruit decay

Question 15

what are linguistic abilities useful for?

Answer 15

sharing information

propagation of species

Question 16

how does the human brain evolve?

Answer 16

Herculano-Houzel et al (207) - brain weight to number of neurons, found primates to have most neurons

neoteny

not all neurons are coded at birth, allowing for learning based on environment

Question 17

what is neoteny?

Answer 17

how large brains are achieved and how neurons are coded for useful functions and cognition

slowing of maturation, allowing time for growth, important for large brain and complexity

Question 18

why study non-human species?

Answer 18

similarities across species in brain structure and function allow use of animal models to understanding brain-behaviour relations (understanding mechanisms, models of neurological disorders)

comparative studies

importance of animal models

importance of comparative studies

Question 19

what are comparative studies?

Answer 19

particular species have advantages

study evolution of the brain

Question 20

why are animal models important?

Answer 20

hippocampal lesions in rats - impaired conditioning to contextual cues, amnesia in humans with hippocampal damage

rat studies tell us which neuronal systems are key

Question 21

what is the importance of comparative studies?

Answer 21

Clayton (1998)

unique source of evidence for the role of the hippocampus in learning and memory

within birds and mammals - hippocampal volume is enlarged in food storing species

hippocampus can change size in response to experience

Question 22

what are evolution shaping psychological mechanisms?

Answer 22

competition vs cooperation

game theory

hawk-dove game

evolutionarily stable strategy (ESS)

prisoners dilemma

altruism

Question 23

what was Von Neumann and Morgenstern’s game theory?

Answer 23

classic definition = mathematical model of strategic decisions

analysis of outcomes based on their own decisions and other players decisions

no control on others decisions

Question 24

what was Maynard Smith and Price’s game theory?

Answer 24

applied in understanding evolution strategies

ESS and Price Equation

Question 25

what is the hawk-dove game?

Answer 25

ESS cooperation vs conflict hawk = aggressive and will take by force (fight) if necessary dove = passive and will avoid conflict or share both encounter a food resource = 1 benefit of acquiring a resource cost of fighting/risk of injury

Question 26

what happens when a hawk meets a hawk?

Answer 26

fight for resource winner gets resource but there is a cost of injury

Question 27

what happens when a hawk meets a dove?

Answer 27

hawk dominates gets resource

Question 28

what happens when a dove meets a hawk?

Answer 28

hawk dominates and takes resource dove gets nothing

Question 29

what happens when a dove meets a dove?

Answer 29

both are passive so share resource each get 1/2 resource

Question 30

what is an ESS?

Answer 30

once adapted by most of population, cannot be invaded by alternative strategy best strategy for survival

Question 31

what are the two conditions for ESS?

Answer 31

strategy should do better than itself than any new competing strategy if it tried to invade strategy should have at least comparable pay off (benefit) than any other strategy

Question 32

how the hawk-dove compare to the two ESS strategies?

Answer 32

in solution, both hawk and dove strategies violate condition 1 hawk strategy (hawk vs hawk = fight and injury, hawk vs dove = hawk wins resource) dove strategy (dove vs dove = peacefully share, dove vs hawk = hawk wins resource) even if dove strategy technically doesn't violate condition 1, it won't meet condition 2 so if hawk enters dove population, it will always get resource so payoff for dove vs dove strategy is not comparable mixed strategy would work best as this is stable

Question 33

what is the prisoners dilemma?

Answer 33

prisoners 1 and 2 arrested for same crime interrogated separately and cannot communicate if both stay silent = one year each if one confess while other stays silent = betrayer free, silent gets 5 years if both confess = each get 3 years

Question 34

what is the paradox in the prisoners dilemma?

Answer 34

best strategy for mutual benefit = both stay silent (1 year each) best strategy for each prisoner individually = confess and implicate the other (0 years) without knowing the other prisoner's strategy (no interaction) = best strategy is still to confess

Question 35

what was the iterated prisoner's dilemma?

Answer 35

Axelrod and Hamilton (1981) - tit for tat strategy biological interactions = assumption is that the same two individuals will meet more than once best strategy for mutual benefit = staying silent cooperation evolves when tit for tat strategy employed if in round 1, prisoner 1 confesses, then round 2, prisoner 2 confesses tested using computer simulation - cooperation emerged as ESS when probability of two individuals meeting was high

Question 36

what is altruism?

Answer 36

behaviour at a cost to oneself but benefit to others (Fehr and Fischbacher, 2003) contrary to natural selection? survival of the fitness - not "strongest" but best at passing on genes those with higher fitness - have more offspring - more frequency

Question 37

what is kin selection?

Answer 37

altruism towards relatives inclusive fitness Hamilton's rule Price's equation

Question 38

what is inclusive fitness?

Answer 38

includes both direct fitness (offspring of an individual) and indirect fitness (offspring in the same species)

Question 39

what is Hamilton's rule?

Answer 39

Hamilton (1963) rB > C r = genetic relatedness B = benefit to recipient C = cost to altruist's fitness

Question 40

what is Price's equation?

Answer 40

mathematically explain how natural selection is connected to inclusive fitness even if there is a cost to individual fitness, if net effect (genetic line) increases (rB), altruism increases

Question 41

how do meerkats show kin selection?

Answer 41

stand guard while others forage reduces guard's individual survival chance/cost (C) relatives benefit in the group (rB) overall chance of survival increase (inclusive fitness) therefore ESS evolves within the population

Question 42

what is non-kin altruism?

Answer 42

why help strangers? reciprocal altruism (Trivers, 1971) group selection

Question 43

what is reciprocal altruism (Trivers, 1971)?

Answer 43

benefits will be reciprocated in a similar situation Price Equation - past cooperation predicts future fitness iterated prisoners dilemma - cooperation builds when its repeated

Question 44

what is group selection?

Answer 44

more cooperation helps dominate selfish groups