9 - EVIDENCE FOR EVOLUTION Flashcards
what are the 7 types of evidence for biological evolution
1 - fossil record
2 - vestigial organs (eg ostrich wings)
3 - dead genes (broken vit C gene in humans)
4 - unintelligent design (flounder eye)
5 - convergent evolution (placental mammals and marsupials)
6 - islands with missing species (almost no freshwater fish on hawaii)
7 - evolution in the lab
- no other theory can have the same predictive and explanatory power as evolution
fossil record
- species that don’t currently exist
- gradual chance over species (same species)
- alternative explanation = intelligent design
vestigial organs
organs that no longer perform the function for which they were evolved
- eg eyes in blind mole rats
- eg human tail
- eg whale pelvis
dead genes
- eg broken vitamin C gene in humans
- PSEUDOGENES
unintelligent design
- eg flounder eye
- eye migrate to other side of head so it can lay on the floor
- eg laryngeal nerve is too long and loops under something when it doesn’t need to
convergent evolution
- eg placental mammals and marsupials
- common ancestors in some cases or that different organisms are adapting to solve the same problem
islands with missing species
- almost no freshwater fish on hawaii
- but find on the continent - don’t disperse into oceans
statement:
biological evolution operates on genes (genotype) to produce proteins, etc, that form the body and behaviour (phenotype)
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psychological traits + polygenic
- most psychological traits are polygenic (influenced by multiple genes)
- high heritability but don’t know which genes cause them
- but heritability suggests it’s genetic
what does the watershed model explain?
- why there is so much variation and so many mental disorders
watershed model + genetic expression
- 55% of coding DNA is expressed in the human brain
- because so many genes are expressed in the brain
- mutations in those genes can add up to causes a cumulative cognitive phenotype which can be influenced by many changes in genome
- small mutations can have larder impacts if accumulated
- eg small molecular changes
- eg genetic precursors
watershed model + random notes
- inherit some organelles from mother (mitochondria)
- biological evolution is 99.9% about genes
mendelian disorders
act as if they’re single cell mutations
- have a particular location on chromosomes
- condition can be seen since birth
- results primarily from alterations in one gene or abnormalities in the genome
darwinian psychology
- psychological traits could be adaptive
- even mental disorders (would be suggested if they have a high prevalence)
- ADHD = could be suggested as adaptive in ancestors
- dopamine DR4 receptor - associated with 7% predictive power for ADHD - high global population level
- low prevalence might be associated with disorder and be selected against
statement:
each human carries about 500-2000 deleterious point mutations inherited from ancestors
- about half of these expressed in the brain
- large variation in genotype that gives rise to phenotype
- spectrums of behaviour
- eg mental disorders, autism, schizotypal spectrum
- deleterious point mutations = mutation which deletes a single nucleotide base from a DNA sequence in a genome
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