Population genetics and natural selection (chapter 4) Flashcards
Darwins 2 conclusions
- Evolution and natural selection
- Organisms can adapt and change over time
Adaptation
Inheritied(genetic) charcteristics of an organism
What drives phenotypic variation and example
Genetics and environemnt
Ex. Peppered moths
Phenotypic plasticity
The ability of one genotype to produce more than one phenotype when exposed to different enviroenments
Temperature dependednt sex determinism and ex.
The nest temperature effects whether and egg will be a male or female organims
Ex. American aligator
Hardy weinberg principle
States that allele and genotype frequencies in a population will remain constant form generation ot generation in the abscence of the evolutionary influences
5 agents of evolutionary change
- Mutation
- Gene flow
- Non random mating
- genetic drift
- Selection
Gene flow
Movement of alleles form one population to another increasing genetic diversity
Non random mating
Organisms with certain genotype are mated more frequently than others
Genetic drift and example
Random fluctuation of an allele and decreses genetic variation
Ex. Bottleneck effect
Selection and examples
-produces adaptive evolutionary change
Ex. Natural and artificial
Sexual selection
Individuals with a certain inherited characteristic are more likely to obtain a mate
Conditions for natural selection
- Variations must exist (good and bad)
- Variations effect number of offspring surviving
- Selected variation must have genetic basis
3 ways selection can act
- disruptive selection
- directional selection
- Stabalizing selection
Why is the overuse of antibiotics and herbicides/pesticides problamatic
Can lead to antibiotic resistance and decresed effectiveness of herbicides and pesticides.
