9B: Environmental Selection Pressures Flashcards

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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
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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

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3
Q

4 Conditions of Natural Selection:

A
  1. Variation: Individuals in a population vary genetically, which leads to phenotypic differences
    1. Selection Pressure: an environmental selection pressure impacts the survivability of organisms within a population and their ability to reproduce
    2. 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.
      1. 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
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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
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