4.4 Genetic Diverstity And Adaptation Flashcards
Why would it be advantageous to have a higher genetic diversity within a population, due to a higher number of alleles within a population?
There will be a higher probability of an advantageous characteristic being present in a population of there was a change in conditions
The advantageous allele could then be passed on to their offspring
Define reproductive success
Define allele frequency
Define gene pool
Define allele
Pass on alleles to offspring
Number of times an allele occurs in a gene pool
Number of alleles within a population
Different form of the same gene
Describe natural selection
4 steps
- There is variation within a species population due to the wide variety for alleles within a gene pool
- Within the gene pool a random mutation of an allele occurs resulting in an advantageous, or most commonly harmful, characteristic
- Organisms with a greater reproductive success leave more offspring that those with less reproductive success
- As a result, the frequency of this allele will increase in the population
What is directional selection?
What is the result of directional selection?
What happens to the frequency graph?
Selection that favours the extreme phenotypes in a range of phenotypes, due to a change in conditions, causing there phenotype to become an advantageous characteristic
Average characteristic changes - extreme phenotype becomes common, other phenotypes become rare
Shift to the right
What is stabilizing selection?
What is the result of stabilizing selection?
What happens to the frequency graph?
Selection that favours the average phenotype in a range of phenotypes due to no change in conditions
Preserves characteristic in population and reduces variation - number of extreme phenotypes decreases
Increase in modal value
Becomes steeper and thinner
Define species
A group of similar individuals that can reproduce reproductively successful offspring
