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Population Genetics and Evolution - Coggle Diagram
Population Genetics and Evolution
Population Genetics
abundance of different alleles within a population
change over time
sexual reproduction
gene pool
Factors that cause gene pool to change
Mutation
occur continually
existing alleles decrease in frequency
new alleles
Accidents
organisms cannot adapt
meteorite strike
all organisms are killed
change in allele frequency
doesn't make species more able to survive another meteroite
in plants
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Artificial Selection
humans purposefully change allele frequency
selective breeding
crops or ornamental plants
artificial mutations
artificial mutagens
UV or Gamma
Natural Selection
most significant factor
survival of the fittest
2 conditions must happen
1
must produce too many offspring
most valid for plants
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2
progeny of alleles must differ
some species must be able to grow taller to absorb light or all die
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can happen even if not all die
differential survival among organisms
does not cause mutations
Other Factors
purpose, intention, voluntary decision making
plants don't choose to be resistant
humans and other primates act with intent and purpose
Situations where natural selection does not operate
can't operate if all individuals are genetically identical
or population cannot adapt
when competition isn't a factor
newly plowed field
all survive
Multiple Selection Pressures
loss is not caused by single factors
plants are affected
insects, cold, drought, pollinators, metabolism
mutations are advantageous or harmful
advantageous mutations can be eliminated from populations
some advantages may hurt in other ways
Speciation
natural selection causes new species
phyletic speciation
1 species gradually changes to a new species
gene flow
physical movement of alleles
pollen transfer, seed dispersal, vegetative propagation
Pollen Transfer
pollen grains carry 1 haploid
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Seed Dispersal
some seeds fall close to parent
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Vegetative Propagation
mobile pieces
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divergent speciation
one species evolves into a new species while part of the species stays unchanged
reproductively isolated
alleles in different ranges can't reach each other
abiological reproductive barriers
non-living feature that prevents populations from exchanging genes
original species dived into groups that cannot interbreed
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biological reproductive barriers
biological phenom that prevents gene flow
mutations can prevent pollinators
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Adaptive Radiation
species rapidly diverges into many new species over short amount of time
few million years
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Convergent Evolution
same phenotypes emerge in separate species
phenotypes favored by natural selection
cacti and euphorbia
genotypes don't converge
Evolution and the Origin of Life
chemosynthesis
origin of life hypothesis
chemical and physical processes
A. Oparin proposed theory
4 conditions necessary for life
the right in organic materials
appropriate energy sources
a great deal of time
absence of oxygen in O2 form
Earth Before Origin Of Life
Chemicals Present in Atmosphere
most of 1st atmosphere lost to space
2nd atmosphere
produced by gases released from rock matric composing Earth
H2S, NH3, CH4 and H2O
found in volcanic gases and meteorites
reducing atmosphere
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Energy Sources
2nd atmosphere complex chemistry
exposed to powerful source of energy
UV and gamma radiation from sun
highly reactive free radicals
heat another source of energy
kinetic energy due to gravity
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Time Available for the Origin of LIfe
time had no limits
lack of free molecular oxygen
if present chemicals not formed or oxidized soon after formation
"dilute/primordial soup"
Chemicals Produced Chemosynthetically
experiments ran in 1953
forms virtually all molecules essential for life
plausible model
Formation of Polymers
Monomers present in early ocean had to polymerize
oceans changed to concentrated soup
high concentrations formed
seaside pools evaporate
pools hot through sunlight with enough energy for polymerization reactions
washed back into sea with high tides
frozen water increases concentration of polymers
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Aggregation and Organization
chemicals into masses that had some organization and metabolism
fatty, hydrophobic material accumulated automatically
1st aggregates formed randomly
"simple metabolism"
possibly heterotrophs
not alive but early stages of life
important for chemistry of ocean
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Early Metabolism
early organisms complete heterotrophs
absorb all material and modifying a few molecules
enzyme capable of synthesizing scarce molecule
2 step long metabolic pathway
aggregates increases
descendants form chemosynthetically
scarcity formed again
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Oxygen
evolution of chlorophyll a and photosynthesis
liberates oxygen
occurred 2.8 billion years ago
created conditions for evolution of aerobic respiration
oxidizing atmosphere
2nd atmosphere plus O2 from photosynthesis
transformed to ozone
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allowed the world to rust
free O2 concentration low
if not for iron free O2 would have killed everything
low level for millions of years
Presence of Life
chemistry of living creatures is more complex than nonliving objects
physics of living and nonliving system is identical
more important to look to understand processes in their complexity
Rates of Evolution
most populations are well adapted to their environments
survive 10's millions of years
seeds on Kauai diverged to 3 species
evolutionary changes that result in loss can come quickly
disadvantageous mutations
Plants and People
Zoos, Botanical Gardens, and Genetic Drift
important factors in conserving endangered species
genetic drift adaptive radiation, artificial selection
can be lost easily
habitat presentation only effective method
very different gene pool in zoos
Yellowstone
forest fires = natural selection
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Search for Life on Mars
water discovered on Mars Europa, Titan, and other bodies
water is essential for life
if life arose independently will be hard to detect
most likely microscopic
metabolism
test soil
nonrandom organization
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Thinking about Thinking
Types
biology based on biblical meaning
evolution proposed several times
applied to every part of biology
"type" obsolete
Botany and Beyond
Species
populations not types
Homo sapiens
population concept of species
variation of same species
Mendel's theory
type population of species
old concept
ideal type
Biblical and Plato
