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Population Genetics and Evolution Screen Shot 2020-10-22 at 1.57.30 PM -…
Population Genetics and Evolution Screen Shot 2020-10-22 at 1.57.30 PM
Rate of Evolution
Evolutionary changes
happens quick
complexity
adaptation
negative consequences
positive consequences
as environment changes
selective
value of the phenotype
may change
Evolution and Origin of life
Aggregation and Organization
chemical evolution
aggregation
chemical components
masses with metabolism
certain types of proteins
RNA
first heritable information molecule.
Formation of Polymers
monomers polymerize
ocean change
concentrated
highly concentrated reactants
Early Metabolism
Energy metabolism
glycolysis
evolved
Oxidative
electron transport
Oxygen
chlorophyll a and photosynthesis
liberates oxygen
world to rust
evolution of aerobic respiration
wasted product
2.8 Billion years ago
combined with
iron and & ferric oxide
oxidizing atmosphere
#
ozone O3
organisms move
higher in the oceans
mud of seashores
terrestrial life
Chemicals Produced Chemosynthetically
chemosynthetic hypothesis
first experimental tests
1953
direct analysis of
meteorites and lunar samples
nonliving
environments
represents
plausible model
Presence of Life
slow, gradual process
inorganic compound
living bacteria
aggregates alive?
Conditions on earth Before the Origin of life
Chemicals Present in the Atmosphere
second atmosphere
release of gases
rock matrix
reducing atmosphere
second early atmosphere
first atmosphere
lost into space
Energy Sources
exposed to
#
powerful sources of energy
UV and gamma
radiation
from the sun
Heat
power reactions
radioactive decay
heavy elements
uranium
and radium
Electricity
abundant
gigantic scale
volcanic lightning
Time Available for the Origin of Life
#
free molecular oxygen
chemosynthesis
most seriously considered hypothesis
attempts to model
origin of life
known chemical & physical processes
Population Genetics
Situations in which Natural Selection Doesnot Operate
example
sides of a road cut
recently burned area
Multiple selection Pressures
must be adapted
to the environment
certain aspect
more important
Factors that Cause the Gene Pool to change
Mutation
occur continually
existing allele
decrease in frequency
all genomes
subjected to
mutagenic factor
Accidents
events to which
organism cannot adapt
example
collision
large meteorite with earth
volcanic eruption
destroys everything
can be
small event
large event
Natural Selection
survival of the fittest
most adapted to an environment
survive
two condition
the population must produce
more offspring
grow and survive to maturity
in the certain habitat
progeny must differ
from each other
in their types of alleles.
differential survival
among organisms that have
different phenotypes
selective force
Competition for water and nutrients
no mutation
Artificial Selection
humans purposefully changes
allele frequency of a gene pool
examples
selective breeding
plants
animals
carried out in conjunction
with
artificial mutation
#
abundance of different allele
within a population
Cross between two plant
A1A1B1B1 × A2A2B2B2
produces offspring
different genotype
A1A2B1B2
gene pool
Factors that Are Not Part of Natural Selection
purpose
planning
intention,
voluntary decision making.
Speciation
Divergent Speciation
reproductively isolated
occurs if gene flow
does not keep
homogeneous throughout
its entire range
two fundamental causes
Abiological Reproductive Barriers
physical, nonliving feature
prevents 2 populations
from exchanging
genes
allopatric/geographic speciation
reproductive barrier
Mountain ranges
rivers
deserts
oceans
Biological Reproductive Barriers
biological phenomenon that
prevents
successful gene flow
sympatric speciation
prezygotic isolation mechanisms
postzygotic internal isolation barriers
hybrid sterility
hybrid inviability
Adaptive Radiation
special case
species rapidly diverges
into many new species
over an extremely short time
genetic drift
can also occur
in mainland population
sudden change of environment
Convergent Evolution
Evolution of
two phenotypically distinct species
strongly resemble each other
usually because
responding to similar selection pressures.
example
evolutionary
convergence of
cacti and euphorbias
Phyletic Speciation
gene flow
movement of alleles
within a population
by
Pollen transfer
wind distribution
animal mediated
vegetative propagation
species produce
mobile pieces that
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seed dispersal
seed/fruit falls
close to parent
long distance dispersal mechanism
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concept
natural selection that caused
new species to evolve
