Exam 1 (Microevolution) Flashcards
microevolution
-evolutionary change within a lineage
-occurs continuously.
Depending upon the organism and the circumstances, it can tranItsform a lineage dramatically over time.
stasis
a lineage may appear to remain the same over time
Macroevolution
origin and extinction of lineages.
It can happen gradually, or slowly
population
smallest unit where evolutionary change is possible.
Population genetics
study of evolution via the observation and modeling of allele frequencies and genetic change in populations of organisms
allele frequency
the proportion of a specific allele at a given locus, considering that the population may contain from one to many alleles at that locus
genotype frequency
the proportion of a specific genotype at a given locus, considering that many different genotypes may be possible.
phenotype frequency (def and how to calculate)
proportion of individuals in a population that exhibit a given phenotype
To calculate the frequency of a phenotype, count the number of individuals with that phenotype, and divide by the total. Therefore, the frequency of the yellow phenotype in the population below is 4/10=.40
Genotype Frequencies-
how to calculate
To calculate the frequency of a genotype in the population, find the total number of individuals in the population with that genotype, and divide by the population size, N
Allele Frequencies
To calculate the frequency of an allele in the population, add the total number of homozygotes for that allele to half the heterozygotes, and divide by the population size, N.
What is the consequence of changes in allele frequency?
Evolutionary change
Hardy-Weinberg Equilibrium
Situation which no evolution is occurring (genetic equilibrium)
Assumptions of the hardy-Weinberg equilibrium
- Infinite population size
- no allele flow
- Random mating
- No selection (equal fitness)
5 different ways in which evolution occurs.
- genetic drift
- allele flow
- mutation
- non random mating
- natural selection
genetic drift
change in allele frequency by random chance. It occurs if a population is not infinite in size.
Allele flow
change in allele frequency that occurs because individuals move among populations.
Mutation
biochemical change in DNA that one allele into another and creates alleles
Non-random mating
evolution that occurs because individuals select mates based on their characteristics.
Natural selection
evolution that occurs because different genotypes have different fitness
heritable mutations
kind that can be passed on to the next generation.
