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Population Genetics and Evolution - Coggle Diagram
Population Genetics and Evolution
Evolution
Deleterious
grow or reduce slowly
die without reproducing
eliminated genes
Beneficial
individuals grow and reproduce
produce greater # of gametes
increase alleles
Mutation
new alleles
new genes
more or less adapted
Phenotype changes
slow process
thousands of generations
millions of years
gradual conversion
Natural selection
one species into another or several species
Population Genetics
Gene pool
total alleles
all sex cells
all individuals of population
Example: Gene A
100 flowers
100 sex cells
1 million individuals
gene pool= 10 billion haploid sex cells
four alleles
Factors that Cause the Gene Pool to Change
Artificial Selection
selective breeding of crops
produce ornamental plants
humans purposefully change gene pool frequency
alter flower color and size
conjunction with artificial mutation
Natural Selection
factor causing gene pool changes
careful attention
conditions
population produce more offspring than can grow and than can grow and survive to maturity
progeny must differ in their alleles
differential survival
different phenotypes
Accidents
organism cannot adopt: collision of meteor with Earth
alleles destroyed
events
Factors not part of Natural Selection
intention
planning
purpose
voluntary decision making
Mutation
occur continually
existing alleles decrease
all genomes subjected
new alleles increase
Abundance of alleles
particular alleles
decrease
remain the same
increase
sexual reproduction: 2 different partners
in population
Speciation
evolve new species
fundamental ways
Phyletic Speciation
beneficial alleles arise
gene flow: moves alleles physically through space
Pollen Tranfer
wind distributes
pollen grains
travels great distance: new seeds made
animal-mediated pollination
Seed dispersal
seed and fruit fall close to parent
long-distance dispersal mechanism
carried by wind, floods. and stream flows
stick to fur and feathers of animals
Vegetative propagation
small mobile pieces reproduce vegetatively
various mechanisms enable alleles to travel to other plants
millions of years
Divergent Speciation
occurs when alleles of one part do not reach individuals of another
reproductively isolated
Abiological reproductive barriers
nonliving feature
prevents two populations from exchanging genes
physical
allopatric
one species divided into two or more populations
cannot interbreed
speciation results
geographic speciation
Examples: mountain range
Biological reproductive barriers
timing of flowering
sympatric speciation
two groups reproductively isolated
grow together
pigment mutation
Evolutionary changes in pollinators
prevents gene flow
different characters
elevation
temperature
humidity
biological phenomenon
prezygotic isolation mechanisms
neither pollination or fertilization occur
act before zygote is formed
barriers prevent moving pollen
species does not remain homogeneous
Adaptive Radiation
divergent evolution
short period of time
example: colonization of islands
species diverges to many
found individuals
offspring of first generation
original gene pool
two sets of alleles
special case
genetic drift
population become heterogeneous
natural selection operative
gene pool change rapidly
diverge based on physical factors of the environment
mainland population
Environment changes suddenly
dominant species eliminated
Convergent Evolution
natural selection
same phenotype in each
species occupy the same habitat
two evolved to resemble each other
example: cacti and euphorbias
Natural selection
Evolution and the Origin of Life
Aggregation and Organization
!st aggregates
form at random
controlled only by relative solubility
Early Metabolism
Formation of polymers
polymerization
Monomers in early ocean
Oxygen
liberated
consequences
1) allowed world to rust
2) create conditions for evolution of aerobic respiration
Conditions on Earth Before the Origin of Life
Chemicals Present in the Atmosphere
1st atmosphere: hydrogen
2nd atmosphere: released gases
bombardment of materials
H2S, NH3, CH4, and water
reducing atmosphere
lack molecular oxygen
presence of reducing agents
Energy soruces
heat: formation of earth
kinetic energy
radiactive decay
electricity: planetary cooling
rainstorms with lightening
release of chemical reactions
volcanoes
UV and gamma radiation
Time Available for the Origin of Life
no limits
lock of free molecular oxygen
The Presence of Life
chemosynthesis conditions
appropriate energy source
time
right inorganic chemicals
absence of oxygen in destructive form
