Population Genetics & Natural Selection Flashcards
Process that changes populations of organisms over time.
Evolution
Provided mechanisms of evolutionary change in population.
Darwin’s Theory of Evolution
When does Darwin convinced that some individuals will have competitive advantage or survival of the fittest.
October of 1838
Characteristics with advantage _______
Unfavorable characteristics _______
“preserved”
“destroyed”
In this year, first draft of theory of natural selection was created.
1842
Summary of Darwin’s Theory of Natural Selection (4)
- Organisms beget like organisms
- There are ‘chance variations’ between individuals in a species — some are ‘heritable’.
- More offspring are produced each generation that can be supported by the environment.
- Some individuals (based on physical or behavioral traits) have a higher chance of surviving and reproducing than other individuals in the same population.
He proposed that differential survival and reproduction of individuals would produce changes in species populations over time.
Darwin (1859)
an evolutionary process that changes anatomy, physiology, or behavior, resulting in an improved ability of the members of a population to live in particular environment
Adaptation
Rare traits (no matter how favorable) would be blended out of a population, preventing change as a consequence.
Blending inheritance
Old name of Gregor Mendel
Johann Mendel
Augustinian monk, developing the facility with the mathematics necessary to complete the theory of natural selection. He also uncovered basic mechanisms of inheritance (stat and prob).
Gregor Mendel
Mendel’s most influential work was done in this species which he subdivided each into manageable characteristics such as seed form, stem length, and so forth.
Pisum sativum (garden pea)
Alternative forms of genes — dominant or recessive.
Alleles
Consist of organism’s observable characteristics, resulted to interactions between genetic makeup of the individual in an environment.
Phenotype
This species of plant was used in the COMMON GARDEN EXPERIMENT (transplantation of 2 or more population of plants in the same or common environment).
Potentilla glandulosa (sticky cinquefoil)
Variation among individuals in form and function as a result of environmental influences.
Phenotypic plasticity
Locally adapted and genetically distinctive populations within a species.
Ecotypes
The process of Natural Selection can (3):
- Act against different segments of the population under different circumstances and can produce quite different results.
- Can lead to change in population; can serve as conservative force, impeding change in population.
- Can increase/decrease diversity within a population.
Types of (Natural) Selection
- Stabilizing
- Directional
- Disruptive
Acts to impede changes or to stop changes in population (against extreme phenotypes; favors the average)
Stabilizing Selection
Have lower rates of reproduction and survival (in stabilizing selection)
Extreme phenotypes
Occurs when one extreme phenotype has advantage over all the phenotypes; favors AN extreme phenotype over the others in the population.
Directional Selection
Favors 2 or more extreme phenotypes over the average resulting to increase in frequency of both smaller and larger individual in the population overtime.
Disruptive Selection
Favors 2 or more extreme phenotypes over the average resulting to increase in frequency of both smaller and larger individual in a population overtime.
