Population Genetics and Evolution
Population Genetics
abundance of different alleles within a population where the amount varies.
Population Concept of Species
similar ranges of variation that occur in species.
Type Concept of species
concept of thinking an entire species is represented by ONE specimen.
Gene Pool
total number of all alleles in all sex cells of individuals of a population.
Artificial selection
occurs when humans purposefully change the allele frequency of a gene pool.
Natural Selection
(causes the most change in gene pool).
"survival of the fittest".
Factors that are not included in natural selection:
- Purpose.
- Intention.
- Planning.
- Voluntary decision making.
Evolution and the Origin of Life
species present today have evolved from those of the past, which evolved from those before them.
Speciation
occurs when natural selection has caused a new species to evolve.
Phyletic Speciation
One species gradually becomes so changed that it must be considered a new species.
Divergent Speciation
where a portion of a population of a species can evolve into a new second species while other populations are relatively unchanged.
Gene Flow
Movement of Alleles physically through a space.
Reproductively Isolated
Alleles that arise in one part of the range do not reach individuals in another part.
Abiological Reproductive Barriers
any non living feature that prevents two populations from exchanging genes.
Biological Reproductive Barriers
biological phenomenon that prevents successful gene flow.
Allopathic or Geographic Speciation
Occurs when a species is physically divided into two or more populations that cannot interbreed.
Sympatric Speciation
occurs when two groups become reproductively isolated even though they grow together.
Prezygotic Isolation Mechanisms
Biological reproductive barriers prevent pollen from moving from one plant to another therefore preventing both pollination and fertilization.
Postzygotic internal isolation barriers where the genomes are considered too different. Two subpopulations must be considered separate species.
Hybrid Sterility
One of the earliest postzygotic barriers. Occurs when two populations interbreed or are artificially cross pollinated and produce viable seed, then the seed grows into a sterile plant.
Adaptive Radiation
species rapidly diverges into many new species over an extremely short duration of time.
Founder Individuals
offspring greatly resemble the first.
Founder
can consist of just one seed. If this is the case its gene pool will consist of it's two allele sets.
Genetic Drift
the erratic rapid change of a gene pool.
Convergent evolution
unrelated species that occupy same/similar habitats may adapt to where they favor one another when natural selection occurs.
Chemosythesis
hypothesis attempt to model the origin of life using only known chemical and physical processes rejecting all traces of intervention.
Atmosphere
Earth's protective layer dated back to 4.6 billion years ago. Composed of gases and dust.
Second Atmosphere
produced by release of gases from rock matrix composing Earth and meteorites.
Oxidizing Atmosphere
atmosphere derivement from the early second atmosphere by addition of oxygen from photosynthesis.
Listed below is a visual representation of Genetic drift.
Listed below is a representation of Convergent Evolution.
Oxygen
one of earth's
breathable gases created from chlorophyll a and photosynthesis.
Presence of Life
Factors that Cause the Gene Pool to Change:
Mutations
Accidents
Artificial Selection
Natural Selection.
Rates of Evolution
monitoring of an allele that changes rapidly.
pollen transfer
seed dispersal
Vegetative Propagation
Energy Sources
heat, uranium, radium
Endless time was available for chemosynthetic organisms due to the lack of free molecular oxygen.
Chemicals Produced Chemosynthetically
amino acids
sugars, lipids, nitrogen bases
and so on.
Polymers* found when monomers undergo polymerization.