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what is natural selection
differencial reproductive success
pass traits on more often than others who don't have it
must be genetically inherited
potential sources of earths molecules
space- asteroids and meteoroids
iron-sulfur process- ocean(hydrothermal vents)
firsts genetic material
RNA enzyme
ribosome
fitness
ability to survive and reproduce
best suited to environment makes more babies
genetic variation
important for natural selection alleles must already exist
die if we cant change genetically if we can species live longer because they can bounce back
directional selection
select for extreme phenotype favor one extreme phenotype eliminating another
stabilizing selection
eliminating both extreme alleles and choosing the intermediate one
disruptive selection
eliminating the intermediate and goes for extreme phenotype
allopatric
the difference from normal/ new home
isolation geographically causes this, too many changes occur which creates different species
sympatric speciation
stay in same environment but have different appearances
2 ways species change in geographic areas
changes in behavior,# of chromosomes
genetic drift
has to be a small population for this to occur
bottleneck effect
randomly reduce genetic diversity, whoever survives is new genetic frequency
founder effect
result of migration, small group leaves population starts a new population allele frequency
vastly different from one they moved away from
equillibruim
no mutations
no gene transferred
random mating
large population
no selection if these are not true
p
q
p2
2pq
q2
dominate alleles homo/hetero
recessive alleles
homo dominate
heterozygote
homo recessive
traits that are selected that allow them to produce more offspring being selected for sex standout but get eat more often due to the stand out traits
fossil record evidence for evolution
we can look for changes that have occurred, link between organisms shows us stages organisms went through
homologous structure
same evolutional history but different function and structure now
evolution
change in allele frequency
microevolutionary dissent with modification
modifying based on environmental structures happens in a population
convergent evolution
things that have similar traits that exist because similar environmental structure
vegistal
evolutionary leftovers organism doesn't need anymore but ancestors have it
biological species concept
able to produce offspring
same species
asexually reproduce