population genetics and evolution
concepts
population genetics
factors that cause gene pool to change
situations natural selection does not operate
multiple selection pressure
rate of evolution
speciation
phyletic speciation
divergent speciation
convergent evolution
evolution and the origin of life
conditions on earth before life
chemicals produced chemosynthetically
formation of polymers from
aggregation and organization
early metabolism
oxygen
presence of life
evolution
gradual conversion one species
into one or multiple species
occurs via natural selection
mutations makes
individual better adapted to environment
individual less adapted to environment
science can't solve morel/ethical issues
biological science inhibited by creationism
crossing over increases population's genetic diversity
AABB x aabb #
AaBb
AaBb
AaBb
AaBb
population concept of species
variations occur in all species
type concepts of species
one type of specimen
foundation of thought
biblical creation
plato's concept
tendency to generalize
represents entire species
theoretically gene pool can remain constant
mutations
existing alleles decrease in infrequence
new alleles increase in infrequence
accidents
event organism cannot adapt to
natural disasters
artificial selection
humans purposely change organism's allele
used to produce ornamental plants
natural selection #
most significant factor in gene pool change
differential survival among organisms
can only act on preexisting alleles
natural selection does not include
purpose
intention
planning
voluntary decision making
all individuals in population are identical
impossible to become adapted to environment
occur in
newly plowed fields
recently cut areas
recently burned areas
insects
fungus
drought
cold
need for pollination
need for mechanism to disburse seeds
most populations well adapted to habitat
few mutations produce new phenotype
rapid speciation in
groups of asters in Hawaii
hard to identify particular alleles
unless it significantly effects phenotype
typically evolution rate is slow
new evolved species
hard to define new species
typically new species when
two individuals can't produce fertile offspring
speciation occurs in two ways
phylectic speciation
divergent speciation
gene flow
physical movment of alleles through space
pollen transfer
pollen grain carry one haploid cell
wind distributes pollen
birds and insects spread poll
typically over short distance
seed dispersal
fruits can be carried by
wind
floods
streams
can make their way to islands
animals
rafting
vegetative propagation
reproductive isolation
abiological reproductive barriers
physical nonliving structures stopping
two populations from exchanging genes
biological reproductive barriers #
leads to allopatric
mountains
biological phenomenon stopping gene flow
factors are
flower color
shape
fragrance
sympatric speciation
two groups unable to
grow together
reproduce with each other
prezygote isolation mechanisms
postzygotic internal isolation barriers
hybrid serility
two sub population unable to interbreed
hybrid inviability
zygote dies during early development
adaptive radiation
species rapidly diverge into many species
all offspring resemble founder individuals
populations small
genetic drift more likely
natural selection favor same phenotype
two species evolve similarly
species tend to resemble each other
examples
cacti
euphorbias
chemosynthesis
consider hypothesis for origin of life
attempts to model origin of life
via chemical processes
via physical processes
primitive earth needed requirements
right inorganic chemicals
appropriate energy source
great amount of time
absence of O2
chemical present in atmosphere
reducing atmosphere
due to lack of oxygen
first atmosphere composed of mostly hydrogen
lost in space
second atmosphere
ammonia
methane
water
energy sources
UV light
Gamma radiation
heat via
coalescence of gas and dust
radioactive decay of elements
lighting from volcanoes eruptioning
time available for origin of life
no limit
oxygen not braking things down
amino acids
sugars
lipids
nitrogen bases
seaside pools
seaside frozen pools
absorption by clay particles
first aggregate formed randomly
not postulated to be alive
RNA possibly first heritable information molecule
early aggregates would be heterotrophs
aggregtas that made enzymes
selective advantage
formation of metabolic pathways
glycolysis #
allowed the world to rust
made selective conditions for aerobes
chlorophyll a evolved
photosynthesis started to make oxygen
all free iron oxidized
oxygen began to accumulate in atmosphere
current atmosphere is oxidizing
chemosynthetic theory does not
determine between living and non-living
physics of living and non-living
systems are identical
Two conditions for natural selection to occur. populations must produce more offspring than can survive and progeny must differ from each other in their types of alleles.
When trying to identify alleles for dominance and recessiveness, two true pure breed homozygous individuals that exhibit different phenotypes must be used.
Mutations can possible lead to biological reproductive barriers.
Glycolysis being an ancient metabolic pathway, it is in all plants and is essential for the plant's lively hood.