Chap 19 Flashcards
Population
Is a group or organisms of the same species that live together in a defined area and time.
Genes
Are carried on chromosomes and controlled in terms of inheritance of traits
Alleles
Each form of a gene
•ex) colour of fur of a mouse
Gene pool
Is the SUM of all alleles for all the genes in a population.
{genetic variation passed on to next gen}
More variety:
Better chance the population can survive
Genotype Frequency
Is a proportion of a population with a particular genotype.
•expressed in decimals
Phenotype Frequency
Is a proportion of a population with a particular phenotype.
•expressed as decimal or percentage
Allele Frequency
Is the RATE of occurrence of a particular gene.
•expressed as decimals
Hardy-Weinberg principle:
Allele frequencies in a population will remain the SAME from one gen to next if it follows 5 conditions.
5 Hardy conditions
- Large Population
- Mating at random
- No mutations
- No migration
- No natural selection
Hardy-Weinberg equation
Determines the frequencies of different genotypes in a population
•p2+2pq+q2= 1.00
Genetic equilibrium
No change in the allele frequencies over time, then the population is at genetic equilibrium. (Hardy-Weinberg equilibrium)
•NOT changing or evolving population
Microevolution
The GRADUAL change in allele frequencies in a population.
•ex) development of DDT-resistance in mosquito
Genetic diversity
The degree of genetic variation within a species or population.
~can be reduced~
•ex) ducks death in a cold winter
Mutation
A change that occurs in the DNA of an individual
•Inheritable mutations= potential to affect an entire gene pool
Gene flow
Describes the next movement of alleles from one population to another due to migration of individuals.
•ex) mating of wolves to increase survival
Non-random mating:
Prevents individuals with particular phenotypes from breeding. Only individuals that mate will contribute to the gene pool of the next gen.
•ex) antlers of Caribou to attract
Genetic drift
A change in our frequencies due to chance events in a small breeding population (lost traits of alleles)
Founder effect
The gene pool changes that occur when a few individuals start a new isolated population.
• frequently on islands (Galapagos)
• lack of genetic diversity in human populations can be medical concerns (Amish)
Bottleneck effect
Gene pool changes that results from a rapid decrease in population size.
•seen in species driven to edge of extinction
Natural Selection
Is the only process that leads directly to evolutionary adaptation.
•Some individuals are able to survive
and reproduce better than others.
~Greater fitness breed passes on to next gen
Heterozygote advantage
Several alleles that are related to genetic health conditions are thought to provide advantages.
•ex) an allele for cystic fibrosis may be better resistant to diarrhoeal diseases as such as cholera.
