week 2- the scientific movements leading to evolutionary psychology Flashcards
what are the 3 pieces of evidence that existed BEFORE DARWIN to lead people to suspect that animals had evolved (changed over time)
- differences between bones of existing animals and fossils
- similarities in bones of existing animals
- similarities in embryonic development
what were jean baptiste lamarck’s 3 main arguments?
- Use vs. disuse- “use it or lose it”- body parts that are used grow bigger over time through secretions of “nervous fluid”
- Acquired changes are passed on to offspring
- Repeated over generations, leads to a new species. A force of nature drives creatures to go from simple to complex
why was lamarck’s ideas rejected for darwin’s?
because of evidence
that acquired characteristics are not passed on to the next
generation (not inherited)
what is darwin’s theory of natural selection?
- Variation- Individuals differ from one another (e.g. in wing
length, bone mass, strength) - Selection- Not all individuals can survive, or reproduce to the same extent. Individuals have characteristics that can help or hinder them in surviving and reproducing
- Inheritance- those individuals who reproduce pass on their characteristics to their offspring
who was Darwin inspired by in his theory?
malthus
what did malthus’ essay state?
Increases in food production
temporarily improve conditions (esp. nutrition) for people.
– However, increases in food
production lead to increases in population, which reduces
average conditions again.
– Increases in food production
lead to greater population, not
higher living standards
what main takeaway did darwin get from malthus?
there will always be a struggle in every generation for
individuals to survive
apply darwin’s theory of natural selection to his finches
- Variation – differently-shaped beaks.
- Selection – some shapes are better for opening
nuts (which may help in the struggle to survive). - Inheritance – beak shape is inherited, and birds with those beaks will become more numerous on that island
apply darwin’s theory of natural selection to african elephants IN TWO WAYS
- Variation – some elephants have bigger tusks.
- Selection – bigger tusks provide both survival and
reproductive advantages. (ex. strip bark off trees, defend against predators, etc.) - Inheritance – tusk size is inherited.
- Variation – some elephants have bigger tusks.
- Selection – poachers selectively hunt and kill
elephants with the biggest tusks. - Inheritance – smaller tusk size is inherited, because all the large tusk elephants are killed
what is darwin’s theory of sexual selection?
although some species have heritable traits that seem to hinder their chances at survival, those traits help their chances at reproducing
what is intra-sexual selection? what does it involve
occurs when members of the same sex compete for mates
-usually there is competition between males for direct access to females and ownership of the territory/resources to attract females
what is intersexual selection
occurs when one sex chooses which members of the opposite sex to mate with
explain why male southern elephant seals have evolved to be larger than females? what type of sexual selection is this
intra-sexual selection
-because the males fight with each other to gain territory on
the beach. When territory is acquired, the male gains
access to females, who arrive to give birth (from the
previous mating season) and then mate again. Larger size confers an advantage to males in these contests; in both fighting and guarding the beach (blubber). So, larger males are more likely to pass on their heritable traits, including size, and larger male seals are born in the species
explain why male elk are more likely to have large antlers, even though it increases their chances of being caught by predators. what type of sexual selection is this?
intra sexual selection
-because large antlers are advantageous in male-male competition (fighting) for females
explain why peacocks have large feathers, even though they increase their chances of being hunted? what type of sexual selection is this?
intersexual selection
-females prefer to choose males with brighter and larger tail feathers, they mate with them, the trait of having larger/brighter tail feathers is passed on
why do female peacocks prefer to mate with males with bright/large tail feathers?
costly signalling- “I could not possibly have survived to adulthood with this ridiculous train unless I was especially fast, strong, or clever. My train shows I must be good at surviving”
what is a genetic drift
Some genetic changes have nothing to do with
selection and adaptation, and are instead more
randomly-caused
what are the two ways a genetic drift can happen?
-founder effects
-genetic bottlenecks
explain founder effects by giving an example
Let’s imagine a literal life raft of people is washed up on a deserted island. Imagine
the raft just happens to contain more redheads
than the general population.
After years of surviving and reproducing, the island
may still contain a greater number of redheads
than in populations of humans elsewhere, even if
being redheaded had no adaptive value per se
what is a genetic bottleneck
When a population shrinks,
for example through a sudden catastrophe, it may leave only a subset of individuals.
how would darwin explain the creation of humans?
– The cooling of the earth led to a reduction in the
size of the African rainforests.
– Those still in rainforest zones went on to evolve
into modern chimpanzees.
– Those whose habitats turned to woodland
savanna had to find new food sources.
– Food (such as fruit) is more widely distributed in
woodlands, which creates selection pressure for
efficient long-distance movement. This may have
led to bipedalism and subsequent change
name 2 problems that darwin faced in his explanations
- He thought inheritence was a literal 50/50 mixing/blending process, but we now know that a child can have no detectable trait of their parents (ex. logic or halsey)
- An explanation of how partial characteristics could be useful (ex. since wings are evolved and no creature is just first born with complete wings, there must have been a reason for partial wings to be useful, but what?)
briefly describe gregor mendel’s explanation of evolution (the modern synthesis of inheritance)
offspring only inherit part (not all) of their parents qualities, the “parts” are alleles, a collection of alleles is your genotype
what is the movement that william james founded? explain it briefly and give an example
functionalism
-suggests that the mind’s primary purpose is to help humans adapt to their environment. This approach emphasizes the overall function of the brain in fulfilling practical needs, rather than analyzing its separate components
(emphasis on physiology)
ex. fear can alert us to danger and trigger our body’s fight or flight response, protecting us from harm
explain behaviourism briefly
Virtually everything is learned (conditioned).
– Very few, if any, innate instincts.
– Any behaviour is conditioned as well as any other
what is ethology
The study of the adaptive value of animal behaviour. A discipline that uses evolution to try to explain animal behaviour
what is imprinting in ethology? give an example using konrad lorenz’s study
a rapid, phase sensitive learning period
ex. ducks don’t know what they are when they are born, they imprint on the first thing they see when they hatch. when konrad’s ducklings hatched, they first saw his leg, and followed it around for life
what is adaptation in ethology?
An evolved solution to a specific problem that increases (directly or indirectly)
reproductive success
give 3 examples of adaptation in ethology
sweat glands- to deal with overheating
taste preferences- to eat nutritious food
ear wax- helps prevent ear infections
give 3 examples of things that are NOT adaptable
-hemophilia
-detached/attached earlobes
-wisdom teeth
what concept did william hamilton introduce to psychology
inclusive fitness
what is classical vs. inclusive fitness
classical fitness is about how many children you have, whereas inclusive fitness is about how many children you have plus your contribution to the survival and reproduction of your genetic relatives (weighted by how closely related to them you are)
why did evolutionary psychology make a comeback in the 60’s? give 2 examples
because although behaviourism was the huge thing, observations that were different to account for by learning alone continued to arise
such as…
-Rats more readily learn to associate nausea
(caused by radiation) with food than with lights or
sounds
-“Which are you more afraid of, snakes or cars?” (but Snake bites = 7 000 - 8 000, 5 fatalities, whereas Car accidents = 40 000 fatalities)
