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Population Genetics and Evolution (Rates of Evolution # (change that…
Population Genetics and Evolution
Rates of Evolution
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very slow process
difficult to identify the process
changes in flowers,leaves, fruits, shoots, trichomes
studies
change that result in loss of metabolism/structure
come about quickly
complexity
Evolution and Origin of Life
species have evolved from those of past
chemosynthesis
chemical and physical processes
A.Oparin
J.B,.S Haldane
right inorganic chemicals
appropriate energy sources
a great deal of time
absence of oxygen in its destructive form
Conditions on Earth Before the Origin of Life
Chemicals Present in the Atmosphere
hydrogen gas - very light
formation of second atmosphere
a lot of gases
molecular oxygen
missing
Speciation
caused by natural selection
new species to evolve
distinct from the species that existed in the beginning
eastern maples and western maples
Phyletic Speciation
species gradually change
must be considered new species
millions of years :warning:
gene flow
alleles spread throughout
pollen transfer
good travel distances
ragweed, grasses, conifers
pollen grains
seed dispersal
seeds and fruits
some fall close to parents
some have long distance dispersal mechanism
wind, floods, streams
vegetative propagation
small, mobile pieces
Divergent Speciation
some evolve into new species, some remain same
not homogeneous throughout its entire range
reproductively isolated
Abiological Reproductive Barriers
physical, nonliving
prevents two populations
original species is divided
cannot interbred
allopatric or geogrphic speciation
Biological Reproductive Barriers
prevents successful gene flow
flower color, shape, or fragence
sympatric speciation
evolutionary changes
Adaptive Radiation
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special case of divergent evolution
species rapidly diverges into many new species
species enter little to no competition
genetic drift
Population Genetics
abundance of different alleles
within a population
manner in which the abundnce
increase
decreases
remains unchanged
crossing over
increases genetic diversity
Factors that Cause the Gene Pool to Change
Mutation
all genomes
existing alleles decrease in frequency
new alleles increases
significance
depends on population size
Accidents
organisms cannot adapt
collision of a large meterorite
example
with earth
large surface is destroyed
all organisms are eliminated
many phenomenas
Artificial Selection
human purposefully change allele frequency
look for desirable qualities
selective breeding of crops
wild population and cultivated plants
selective breeding of animals
Natural Selection
survival of the fittest
most adapt to the environment survive
More offsprings produced than can survive
individuals have different characteristics/traits
inherit traits from parents
different phenotypes
from differential survival
Concepts
Evolution
gradual conversion
one species to another, even more
natural selection
mutations
new alleles or new genes
affect fitness of the individual
more or less adapted to environment
if beneficial
reproduce better
if deleterious
reproduce slower or die
slow process
