Natural Selection Flashcards

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1
Q

Definition of evolution

A

Gradual change in the inheritable characteristics of a population over time

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2
Q

Why does evolution happen?

A

Driven by variation (of traits) and competition (for resources) between individuals (of the same species) of a population, leading to differential survival of and reproduction by, organisms which are best fitted to the environment

-mutation creates new alleles and increases the genetic variation in a population results in variation (traits / phenotypes) between individuals
-organisms with selectively advantageous traits are more likely to survive and reproduce
- individuals produce many offspring which results in competition

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3
Q

Examples of environmental factors that can exert a selection pressure

A
  1. Biological factors
    a. presence of predators
    b. presence of pathogens / disease
  2. Resource availability
    a. availability of food / water
    b. availability of shelter
  3. Physical factors
    a. temperature
    b. weather conditions
    c. natural disasters
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4
Q

Template answer

A
  • selection pressure is exerted by [environmental factor]
  • individuals with selective advantageous [traits] are more likely to survive than individuals which do not
  • these individuals can reproduce, and pass down their alleles to their offspring
  • over many generations there are more individuals with the [advantageous phenotype] in the population
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