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25 Cards in this Set

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Hybridization

The crossing of two different species that share common genes
Directional Selection
Natural selection that changes the distribution of a trait to favor one extreme phenotype
Stabilizing Selection
Intermediate phenotype becomes more common in a population
Normal Distribution
A population that is not undergoing natural selection

Mutation

A random change in the DNA of a gene which can cause genetic variation
Founder Effect
loss of genetic variation that occurs when a new population is established
Intrasextual Selection
Competition among the males to mate

Bottleneck Effect

Genetic variation is lost - Disaster
Distributive Selection
Intermediate phenotypes or selected against both extreme phenotypes
Genetic Drift
Changes in allele frequencies within a population

Allele Frequency

A measure of how commonly a particular allele occurs in a population
Speciation
Is the divergence of two or more species from an existing one
Behavioral isolation
A difference of chemical scents between two populations.

Genetic Mutations

Are random

Enzymes

Increase the rate of chemical reactions
Divergent Evolution
Evolution towards different traits and closely related species

Mutations and Recombination

Two main sources of genetic variation

Coevolution

Species evolve in response to changes in each other
Collisions with asteroids in meteorites
Contributed to the intense heat of the Hadean eon

Lipid membrane hypothesis / Liposomes

Act as barriers between organic molecules and the environment
The discovery that RNA can self-replicate
Supports the hypothesis THATRNA was the genetic material in the earliest organisms
Through the process of Endosymbiosis
Bacteria may have evolved into mitochondria

The Miller-Urey

Demonstrated the energy from lightning might have help create earth's first organic molecules

Cyanobacteria

Changed the earth by adding oxygen to the atmosphere
Cell walls
Found in plant cells, but not in animal cells