Evolution of population Flashcards
What are the sources of genetic variation?
Mutation, Recombination, and Hybridization
What is mutation
a random change in the DNA of a gene
What is recombination
occurs during meiosis which form a new combination of alleles from parents alleles getting arranged in new ways.
what is Hybridization
The crossing of two different species.
What is a populations gene pool?
all the alleles in a population
What are the three types of selection?
Directional, stabilizing, and disruptive
What does directional do?
It favors phenotypes of one extreme, shifts graph horizantally.
What does stabilizing do?
Favors the intermediate phenotype, extremes are favored against. Stretches graph vertically.
What does disruptive do?
Favors both extreme phenotypes, intermediates are favored against. Graph has two peaks like an M.
What is the most common kind of selection?
Stabilizing selection
What selection most likely results in speciation?
Darwins theory of evolution can best be described as…
species arose through gradual transformations
What is genetic variation?
It increases the chance of a population surviving and leads to phenotypic varitation
What is sexual selection?
when certain traits increase mating success.
What type of population is most susceptible to loss of genetic variability as a result of genetic drift
What is gene flow?
the movement of alleles between populations, keeps neighboring populations similar, and occurs when individuals join new populations and reproduce.
What are the two types of genetic drift
bottleneck and founder
What is the bottleneck effect and how does it happen
Occurs when an event drastically reduces population size like a flood or storm.
What is the founder effect and how does it happen?
The founding of a small population, it occurs when a few individuals start a new populations.
why does genetic drift have negative effects on a population?
Causes a loss of genetic variation and harmful alleles can become more common due to chance
What is Hardy-Weinburg equilibrium
a type of model that descirbes populations that are not evolving, biologists use this to study populations.
What are the 5 conditions that must be met in order to say a population is in equilibrium?
Very large population no genetic drift, no gene flow, no mutations, random mating: no sexual selection, no natural selection: all traits aid equally in survival
What is the equation for H-W
p^2+2pq+q^2
Explain the statement “a population is in genetic equilibrium”
The population is not evolving.
How do mutations affect genetic equilibrium
they add alleles to the gene pool.
What type of things would disrupt gene’ tic equilibrium?
mutations, natural selection, sexual selection,gene flow, genetic drift
