Topic 35: Population Genetics 2 Flashcards
Explain the different types of variation in a population.
Types of Variation:
Genetic Variation: caused by difference in genes or other DNA segements.
Phenotypic Variation: influenced from the environement rather than the genetic differences. DNA does not change.
Muatations: Caue changes in an organisms DNA by errors in DNA replication. Mutations can be harmful and beneficial.
Mutations in plants and animals are low, but for viruses and prokaryotes they accumulate very rapidly.
**Sexual Reproduction(gene recombination) **: a shuffle of existing alleles into new combinations. Recombination of alleles is more important.
Describe how these different forces can lead to different outcomes in terms of the population variation.
These forces lead to different outcomes as it changes alleles, recombines chromsomes, introduces variation to a population.
Determine what type of selection process leads to Stabilization, Directionality, or Diversification.
The type of selection process is that of Natural Selection: mechanism of evolution where the organisms that are most adapted to their environemtn are most likely to survive and pass those genes that aided their succes.
Stabilization: Moderate phenotype is selected. The average phenotype is selected.
Directionality: Where one phenotype is favored over the other casuing the allele frequency to continually shift to one direction.
Diversification: The two extreme henotypes are selected over the moderate or average phenotype.
Compare and contrast Sexual Selection and Natural Selection.
Sexual Selection is the attraction of mates to each other in order to gain traits that enhance species survival.
Natural Selection is the where organisms that are most adapted to their environment are most likely to survive and those favored traits are passed down to their offspring.
Sexual selection is due to mating succes and natural selection is about having the best fitness of an organisms into their environment.
Both contribute to evolution that results in changes overtime.
Describe heterozygous advantage and why deleterious alleles can persist in a population.
Heterozygous advantage is a type of balancing selection where heterozygotes have a higher fitness than both homozygotes.
ex: is sickle cell and malaria. AA is not protected from malaria, Aa is protected and does not have sickle cell, and aa has sickle cell and is protected from malaria.
The mutations of deleterious alleles can keep rising in the population.
Deleterious alleles lowers the fitness of the organism.
