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evolution, 11.1 Genetic Variation Within Populations - Coggle Diagram
evolution
11.4 Hardy-Weinberg equilibrium
No mutations
Random mating
No gene flow
No natural selection
Very large population
The Hardy-Weinberg equation can be used to predict genotype frequencies for simple dominant recessive traits in a population.
The Hardy-Weinberg equilibrium told us how can a population evolve:natural selection,sexual selection,Mutation,gene flow,initial population
11.6 Patterns in Evolution
Convergent evolution
when unrelated species evolve similar
characteristics.
The wings on birds and insects are examples of
convergent evolution.
Divergent evolution
when closely related species evolve in different directions, and become increasingly different
The kit fox and the red fox
Coevolution
the process in which two or more species
evolve in response to changes in each other
The theory of punctuated equilibrium
long periods of little change (equilibrium) are interrupted (punctuated) by shorter periods of intense evolutionary events, such as speciation.
adaptive radiation
results in many different species spread out in different
environments
11.2 Natural Selection in Populations
Natural selection acts on distributions of traits.
normal distribution
The frequency is highest forthe middle, or mean phenotype, and lowest at the two ends, or extreme phenotypes.
Natural selection can change the distribution of
a trait in one of three ways.
Directional Selection
Selection that favors a phenotype at one
end, or extreme, of a range
Stabilizing Selection
Selection that favors the middle, or
intermediate, phenotype
Disruptive Selection
Selection that favors both extreme phenotypes
Microevolution
The observable change in the allele frequencies of
a population over time.
11.3 Other Mechanisms of Evolution
gene flow
The movement of alleles from one population to another is called gene flow.
Gene drift
Bottleneck effect
The bottleneck effect is genetic drift that occurs after a population has been greatly reduced in size.
founder effect
occurs after a small number of individuals begin to live in a new area.
sexual selection
Sexual selection occurs when a trait increases mating success, and gets passed on to the next generation.
.
Genetic variation in a population
increases the chance that some individuals will survive
gene pool
Made up of all of the alleles of all of the individuals in apopulation.
Different combinations of alleles in a gene pool can be formed when organisms mate and have offspring.
allele frequency
A measure of how common an allele is in a population
Genetic variation comes from several sources
Mutation
A random change in DNA that can result in a new allele
Mutation can be passed on to offspring and increase the genetic variation in a gene pool.
Recombination
New allele combinations form in offspring through a process
It usually during meiosis and parent's allele arranged in new ways in gametes
Hybridization
The crossing of two different species
11.5 Speciation Through Isolation
reproductive isolation
geographic isolation
behavioral isolation
temporal isolation
speciation
the process of one species becoming two or more separate species.
11.1 Genetic Variation Within Populations