Chapter 11.3 Flashcards
GENE POOL
Is an population entire collection of genes and their alleles
EVOLUTION
Is the change in allele frequencies
To calculate GENE FREQUENCY
1 gene frequency is calculated as the copies of that allele, divided by the total number of alleles in that population
copies of alleles/ by the total # of alleles in the population
GENOTYPE FREQUENCIES
It is the number of individuals with that genotype divided by the total size of the population
individuals with that genotype/ population total
What determines the genetic characteristics of a population
Allele and genotype frequencies
What drives evolution
The shifting alleles fequencies in a populations are the small steps of change that collectively drive evolution
HARDY -WEINBERG EQUILIBRIUM
Is the highly unlikely situation in which allele frequencies and genotype frequencies do not change from one generation to the next
p +q=1 ( represents frequency of both alleles of a gene in a population of a diploid organisim-if only 2 alleles exist for a gene
e.g: If D= frequency of dark fur allele=.06
d= frequency of tan fur allele=.04
D +d = 1 ( .06 + .04=1)
1= The 2 alleles=all the possible allele in a population
When does HARDY -WEINBERG EQUILIBRIUM occur
- mutations do not occur: thus new alleles do not arise
- Individuals mate at random
- Individuals to not mate into or out of a population
- The population is infinitely large enough to eliminate random changes in allele frequencies ( genetic drift)
- natural selection does not occcur
What is the direct measure of evolution
Changes in allele frequencies
how can we use Hardy -Weinberg Equilibrium to calculate allele frequency
**At ** Hardy -Weinberg Equilibrium we can use allele frequencies to calculate genotype frquencies
p= frequency of allele D
p2=Those with the allele DD ( p xp) ( .06x.06)
q2= dd ( .04x.04)
Heterozygous = pq
The formula for all the population allele frequency to include heterozygote and homozygote
Since heterozygote and homozygote account for all the possible genotypes in the populationthe sum of their Frequencies must add up to one(1)
p2 +2pq+q2=1
homozygote dominant +(2 heterozygotes)+ homozygotes recessive=all the alleles in a population
If the Hardy- Weinberg equilibrium are met what will occur in future generations
Their allele and genotype frequency will not change
GENOTYPE
an individuals combination of alleles for a particular gene
Allele frequencies always change. When does this occur in a population
- mutation intrduces new alleles
- Nonradom mating (closed groups mate among themselves intead of the larger population)
- individuals migrate among populations
- change due to chance (Genetic Drift)
- some phenotype are better adapted to the environment than others ( natural selection)
- No population is infinitely large
7.
Why is Hardy Weingerg Equilibrium important
It serves as a basis of comparison to reveal when microevolution is occuring