9B: Environmental Selection Pressures Flashcards
1
Q
Environmental Selection Pressures:
A
a factor in the environment that impacts an organisms ability to survive and reproduce
- E.g. Predation, disease, competition, climate change
- Determines which phenotypes are considered fitter and advantageous
2
Q
Natural Selection:
A
a mechanism through which organisms that are better adapted to their environment have an increased chance of surviving and passing on their alleles
3
Q
4 Conditions of Natural Selection:
A
- Variation: Individuals in a population vary genetically, which leads to phenotypic differences
- Selection Pressure: an environmental selection pressure impacts the survivability of organisms within a population and their ability to reproduce
- Selective Advantage: Individuals with phenotypes that are fitter or more advantageous under the environmental selection pressures are conferred a selective advantage, allowing them to survive and reproduce more successfully.
- Heritability: The advantageous trait must be heritable, allowing it to be passed on from the parents to their offspring. Therefore over time, the frequency of the advantageous allele will increase
4
Q
Evolution:
A
the change in the genetic makeup of a population over successive generations
- As advantageous traits become more common, allele frequencies change, decreasing genetic diversity