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Evolution - Coggle Diagram
Evolution
Races
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Subjectivity
Egyptians, Linnean, Blumenbach and Census all have different classifications
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History
Egyptians had four categories: Aamu, Nehesu, Reth and Themehu
Piny the Elder said people fit in 3 categories: civilised, barbarians and monstrous
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Scientific Revolution in European societies, and Linnaeus classified species under binominal nomenclature
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Franz Boas
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determined that cranial formation was dependent on cultural factors and behaviour on social learning
Darwin
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Limitations
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used blending inheritance where the offspring was a mixture of parents, this would not work with natural selection since variation would be averaged out
no fossil records linking ape to man, so Haeckel used nonwhites as intermediate
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Forces of Evolution
Selection
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Artificial
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Waddington
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he called the tendancy to develop particular traits when stimualted plasticity and tendancy to keep traits despite conditions canalisation
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Sexual
selective pressure affects reproductive success rather than survival, so favours traits for attraction
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Genetic Drift
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bottlenecks- population number drops dramatically, and the remaining population's allele frequency is often different
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DNA
A gene is a basic unit of heritable info, alleles are a different version of a gene
Mutation
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typically more mutations out of genes, so DNA between genes will not harm the organism
Synonymous mutations do not affect protein structure and are more common in cross-species comparisons since they are less likely to be weeded out
Point mutation
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cytosine methylation- methyl added to cytosine which converts to thymine after hydrolytic deamination
Insertion/deletion
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Transposons- addition of DNA fragments either when RNA is reversed transcribed to DNA and added (class I) or DNA is removed and added elsewhere (class II)
Chromosomal
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translocations- transfer between non-homologous chromosomes, exchange can be balanced or unbalanced
Epigenetics
variation in gene expression which can be affected by the environment but does not change underlying DNA
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Cultural evolution
"It was culture... that allowed humans the adaptive flexibility to colonise the world"- Laland and Brown (2002)
Cumulative culture
building one cultural innovation onto another to create a complex pattern and often better served for its function
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great apes have certain cultures (Chimpanzees had different enough behaviour patterns that it wasn't just social practices - Whitten et al, 1999)
Example- farming (~6kya) in near East, this allowed development of storage so higher population densities which affected genetic structure of the populations
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Macro-evolution
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Traits change together
cross cultural analysis of pastoralism effects in sub-Sahara Africa: acquiring cattle changed matrilineal to patrilineal or mixed descent because more cattle made a man more wealthy which increased reproductive success
Co-evolution with genes
"Hominid species have reliably inherited two kinds of information, one encoded by genes, the other by culture"- Feldman & Laland, 1996
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Genetic Variation
Common ancestors
estimate most recent common ancestor lived 100,000-200,000 ya
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Phenotype
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Temperature changes
cold- metabolic rate increases, shivering, vasoconstriction
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Human adaptation
Skin colour
Polygenetic trait, like MCR1 and MRSD12 which affect melanin
linked to latitude
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lower latitudes have higher UV, so higher sunburn risk, skin cancer and folic acid deficiency
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Higher Altitudes
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Adaptations
EPAS1 mutation inhibits production which helps long term exposure effects like clotting from too much haemoglobin
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Adjustments
Polyphenism is the ability of a single genotype to produce multiple phenotypes when exposed to different environmental condition
Behaviour
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Sherman and Billing (1999)- cultures closest to equators use more plant spices with nacteria-inhibiting phyovhemical properties (help with spoilage)
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History
Early questioning
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Slavery
Monogenism- people are the same, but this was challenged by different races
Polygenism- Africans and Europeans have no common ancestry, so rationalised slavery
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Individuals
Charles Lyell
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discovered Earth is much older than suggested in Bible (6,000 years)
David Strauss
wanted to look at the meaning of Bible, rather than its accuracy
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Ibn Battuta
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recorded in book called "A gift to those who contemplate the wonders of cities and the marvels of travelling")
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Bronislaw Malinowski
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he lived with Trobrianders and realised that their culture was not savage but rather fulfilled the needs of the people
he developed a theory that said each culture functions to satisfy the needs of the people, it was criticised for overemphasising individuals
Franz Boas
he insisted that physical and behavioural differences among racial groups was shaped by social conditions and not bioloyg
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Argument
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this was challenged by fossil records which suggested large changes and then stagnation (punctuated equilibria)
Jay Gould
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he also researched extinction and said background extinction was due to competition and mass extinction due to disaster
Attraction
Cultural
some forms seem to appear repeatedly, spread more rapidly and/or are resistant to change
certain ideas are common or even universal (marriage, stories etc)
people do not blindly copy and construct their own versions and opinions but there are cognitive constraints
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