Allele frequency - species and speciation
Breif revision notes on allele frequency, species and speciation
- Created by: Agnes Fitzpatrick
- Created on: 12-11-13 17:50
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- Allele Frequency
- Affected by mutation
- harmful allele frequency decreases
- change in base sequence and resulting in change in protein structure
- neutral maintains frequency
- beneficial allele frequency increases
- higher chance of survival or reproduction so they pass genes down
- causes selection pressure
- Species and speciation
- relies on isolation
- stops gene flow
- allopatric speciation is mainly geographical isolation
- barriers
- oceans
- mountains
- motorways
- sympatric speciation
- behavioural isolation
- feeding times/courtship
- temporal isolation
- mating seasons
- mechanical isolation
- reproductive organs
- habitat isolation
- within same area occupying different levels
- gametic isolation
- gametes fail to "recognise" each other so don't reproduce
- pre-zygotic mechanisms
- allopatric speciation is mainly geographical isolation
- barriers
- oceans
- mountains
- motorways
- prevent fertilisation
- allopatric speciation is mainly geographical isolation
- behavioural isolation
- post-zygotic isolating mechanisms
- low hybrid zygote vigour
- fail to develop properly
- low hybrid adult viability
- offspring don't develop properly
- hybrid infertility
- offspring infertile
- low hybrid zygote vigour
- natural selection and evolution
- species = animals which can successfully reproduce to produce fertile offspring
- results in gene flow between organisms
- relies on isolation
- relative frequency of an allele within population
- Affected by mutation
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