Evolution & Selection 🐣🐤🐔🐓 Flashcards
A populations gene pool ?
The sum of its total alleles
An individual’s fitness ?
An organisms ability to meet the demands of the environment
Gene ?
Piece of DNA that codes for a protein and a characteristic (hair colour)
Allele ?
A form of a gene
Two types of selection ??
Natural and artificial
…selection
Natural selection = ?
The process which some organisms live and reproduce and others die before reproducing
Selection pressure ?
Something in the environment that causes some organisms to love and some to die!
E.g. Antibiotics, pesticides, snow, predators
Survival of the fittest process?
- genetic variation in a population
- random mutation causes a gene for a new characteristic
- if it’s a gene for a good characteristic, organism more likely to survive
- more likely to reproduce
- more likely to pass on good allele to offspring
- good allele frequency increases!!
The theory of evolution is driven by….?
Natural selection
Artificial selection??
Occurs when a breeder chooses individual with a desirable phenotype for breeding and/or prevents those with less desirable phenotype a from breeding»_space;> changing allele frequency in a population
Selective breeding ??
Domestic animals and crop plants that have been subjected to artificial selection
Artificial selection causes….
Decreased genetic diversity as only some alleles are chosen!!!
Genetic drift ?
A change in allele frequency that occurs by chance
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This is particularly noticeable when a small no. Individuals are separated from the rest of a large population
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The effect of drift becomes increasingly important as the size of the population decreases
Give one example of genetic drift???
The bottleneck effect
Process of the bottleneck effect??
- an event or catastrophe drastically reduced the number of organisms in a population
- the variation in the population is reduced
- reducing the allele frequency within a population
- reducing the genetic diversity within a population
