Introduction + natural selections + neodarwinism

Importance of E.O. WIlson (1975) Sociobiology: The new synthesisvff

Took the evolutionary approach of ethologists but focused on function (ultimate expl.) rather than stimuli (proximate)

What did Margaret Mead believe

That cultures differ due to social aspects, rather than biology, e.g. learning + SSSM (standard social sciences model)

What was the New Synthesis accused of

biological determinism

Why did evolutionary psychology arise

In response to criticisms of sociobiology

What does evolutionary psychology focus on

• Evolved solutions to ancestral adaptive problems

• selection for evolved psychological mechanisms, not behaviour

• focuses on human universals

mental organs

specific neural connections/ parts of the braid that are evolved to solve specific problems

What are some universal characteristics of human nature (5)

• expression and experience of emotions (Ekman)

• spoken language

• status and roles including division of labour

• incest avoidance

• developmental trajectories

EEA meaning

environment of evolutionary adaptedness

Where did 99% of the evolutionary history of Homo take place

African savanna during Pleistocene (1.7Ma-10ka)

Why is the EEA concept limited (5)

• little known about EEA

• long evolutionary history before then (too much focus on EEA)

• diverse habitats (don’t only live in Savannah environments)

• not evident that modern hunter-gatherer s are representative

• humans are still evolving

Other critiques for evolutionary psychology

• still pan-adaptationist + just-so storytelling

• out of date understanding of evolution

• domain general psychology

• human universals overlook importance of variation

Behavioural ecology

Contrast with EEA: adaptive responses to local environments

Goal is to determine how differences among individuals can be due to optimality + fitness explanations (fitness is the differential survival/ reproduction of individuals)

Interested in adaptive solutions rather than proximate mechanism

Where did behavioural ecology start

DeVore, studied baboons and !Kung

Adaptability

Degree to which a species can survive and reproduce in different environments

Facultative vs obligate

Facultative: behaving in a certain way IF WE WANT

Obligate: having to behave in a certain way

Optimal foraging theory

What is the best possible strategy to survive and reproduce? Use proximate currencies to determine this (can be optimised, e.g. search time, predation risk)

Niche

Environmental and way of life of an organism, Greater overlap between organisms, e.g. body size leads to greater competition

Fact about sickle cell anemia

Those with SCA are malaria-resistant, creating an overlap. SCA is harmful, but adaptive to malaria

Carpentered niche

Muller-Lyer illusion: those who don’t live in environments with buildings etc. won’t see the illusion

Critique behaviour ecology

• focused on adaptive behaviour (current) but not on adaptations (past- psychology)

Ultimate vs proximate causations - Mayr

Ultimate → refers to evolutionary levels of explanation

Proximate → refers to immediate circumstances

Tinbergen’s 4 questions

Ultimate (why):

• Function (adaptation)- fitness value of a trait

• Evolution (phylogeny)- evolutionary history of a trait

Proximate (how):

• Development (ontogeny)- trait’s variation throughout development

• Causation (mechanism)- immediate circumstances affecting a trait

How many species are there? How many of these are beetles

3-30milllion, 1 million are beetles

What are the 4 core principles of natural selection

• variability

• heritability

• surplus offspring

• non-random survival + reproduction

Correct way to define/ differentiate a species

Mating that produces viable offspring (able to also reproduce)

Vertical transmission

When variability is transmitted from generation to generation (heritability)

Lamarkianism

Inheritance of traits directly from parents: but this means that there’d be no variability, so this idea is not true

Carrying capacity

Amount of offspring that can be supported by environment: anything more than this lead to surplus offspring (leads to population growth to stabilise rather than be exponential)

Blind watchmaker theory

Idea that complexity cannot arise by chance, however evolution refutes this

What are the 4 fitness F’s

• fighting

• feeding

• fleeing

• fu** (reproduction)

Phyletic gradualism

Changes accumulate slowly overtime

Punctuated equilibria

Species experience long periods of stability, but then are interrupted by brief, rapid changes leading to new species

Adaptive lag

Still being adapted to old evironment

Genetic drift

Random change due to chance

Population bottleneck and founder effects

Sharp decrease in population size, so there is a decrease in genetic diversity. Founder effects: traits of the leftover populated are more disproportionately represented in particular population that others

Mendelian inheritance

Variation is maintained across generations, doesn’t just blend/ get destroyed

Law of segregation (Mendel’s 1st law)

We all have 2 copies of particles for a trait, pairs of these particles segregate and get passed into different sex cells

Law of independent assortment

Particles for different trait assort independently

When can traits be blended? (3)

• seems blended because trait is polygenic

• codominance: both alleles full expressed

• incomplete dominance- blend of parental traits

Molecular genetics

Explains how we get from genotype to pheontype

Pleiotropy

One gene has many effects

Protein functions (4)

• structural functions, e.g. collagen

• enzymes

• hormones

• regulatory proteins

What process reflects DNA polymerase producing more DNA

replication

What process reflects DNA polymerase becoming RNA polymerase

transcription

What process reflects RNA polymerase becoming a protein

translation

Ways of studying molecular genetics (6)

• twin studies

• genetic manipulation

• SNP

• gene sequencing

• gene expression

• CRISPR

What is Neo-Darwinism (modern synthesis)

fusion of Darwinian evolution by natural selection and Mendelian inheritance

What are other forces that change allele frequencies in populations?

• mutation

• gene flow

• genetic drift (founder effect)

• non random mating (artificial selection)

• meiotic drive (selfish gene more likely to be passed on)

The selfish gene - Richard Dawkins

Genes act in ways that maximise their own replication + survival. Selection acts on genes, not individuals

Population genetics

Looking at evolution within a population: change in allele frequencies overtime

Analogies vs homologies

Analogies: convergent/parallel evolution, independent evolution produces analogous traits

Homologies: adaptive radiation- similarity by descent produces homologous traits. Same body plan that reflects same evolutionary history

vestigial trait

traits that have lost their function due to evolution, e.g. appendix, tail bone, bone in ear, phobias

exaptations

traits that serve a different purpose than the one they were adaptive for (pre-adaptions/ co-opted traits)

developmental byproducts

traits that arise as a byproduct for a selected trait somewhere else, e.g. men having nipples

maladaptation

traits adaptive in environment in which they evolved, but not now when there is a superabundance, e.g. sugar

phylogenetic inertia

limits on what can evolve due to previous adaptations. physical + genetic constraints, e.g. pigs flying is just impossible

Orgel’s Second rule

evolution is purposeful: comes up with ways to develop complex traits NOT natural selection

Inevitability of evolution

species + traits are NOT destines, outcomes of life would be different if done again

‘For the good of the species’

Natural selection doesn’t do this; takes a gene’s eye view. Acts have to benefit the actor by increasing something

Is-ought fallacy (Hulme’s Law)

distinction between descriptive and normative statements. Just because something evolved one way, doesn’t mean we ought to act that way, e.g. men stronger so they should be aggressive?

naturalistic fallacy

goodness (morality) cannot be reduced to natural properties, e.g. pleasure (sugar tastes good but isnt)

Social Spencerism

principles of natural selection should apply to economies?? Big companies should be ‘favoured’ and are more adaptive than smaller ones