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Population Genetics and Evolution (Evolution and Origin of Life…
Population Genetics and Evolution
Population Genetics
abundance of different alleles
population concept of species
characteristic variation
type concept of species
based on types
gene pool
total number alleles
all sex sells
all individuals of population
Change in gene pool
Mutation
accidents
organism cannot adapt
natural disaster
artificial selection
purposeful change allele
selective breeding
produce ornamental plants
natural selection
survival of fittest
two conditions
overproduction of offspring
progeny must differ
NOT natural selection
purpose
intention
planning
voluntary decision making
multiple selection pressures
multiple factors needed
drought, insect attacks, cold
pressures not universla
improved fitness
Speciation
new species evolved
#
caused by natural selection
phyletic speciation
changed to new species
gene flow
physically moving alleles
pollen transfer
seed dispersal
vegetative propagation
divergent species
new species
OLD POPULATION REMAINS
#
reproductively isolated
two regions
on region yes
one region no
abiological reproductive barrier
nonliving feature
prevents gene exchange
allopatric
2+ populations
cannot interbreed
geographical speciation
mountains
biological reproductive barriers
prevents successful gene flow
sympatric speciation
two groups reproductively isolated
grow together
prezygotic isolation mechanisms
act before zygote formation
postzygotic internal isolation barriers
genomes too different
two subspecies made
hybrid sterility
sterile plant produced
hybrid inviability
early embryonic death
adaptive radiation
rapdi divergance of species
short time
founder individuals
two set sof alleles
look like the founder
Convergent Evolution
unrelated species cohabit
species resemble strongly
cacti evolving
were leafy greens
desert formed mmutations
Evolution and Origin of Life
chemosynthesis
hypothesis of life on earth
Conditions on Earth Before Life
CHemicals present in atmosphere
first ONLY hydrogen
second atmosphere
release of gases from rock
reducing atmosphere
early second atmostphere
lack of molecular oxygen
presence powerful reducing agenets
energy sources
heat
gas and dust on earth
radioactive decay
uranium
radium
UV and gamma
the sun
time available for origin of life
no limits
NO OXYGEN
no breakdown
Chemicals produced chemosynthetically
S.Miller
first chemosynthetic hypothesis
discovered
what happens in normal environments
direct analysis of
meteorites
lunar samples
formation of polymers
monomers polymerized to give life
arise seaside
aggregation and organization
#
masses with metabolism
accumulated
early metabolism
evolved early
oxygen
allowed qworld to rust
aerobic respirtation conditions
presence of life
complicated
Rates of Evolution
slow
speicies mostly adapted
changes caused by extreme conditions
