Heredity: Natural Selection Flashcards

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1
Q

Variation

A
  • crossing over (prophase I)

- independent assortment of chromosomes metaphase I &II)

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2
Q

Why variation is impt

A
  • mutation provide new alleles to gene pool for genetic variation to act on
  • impt to help organisms adapt & survive
  • changing environments
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3
Q

Define natural selection

A
  • process that ensures best adapted organisms in population survive
  • reproduce, pass on genes to next gen
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4
Q

What nature selects

A
  • varieties of organisms that are:
  • more resistant to diseases
  • btr adapted to changes in environment
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5
Q

Define evolution

A
  • simple ancestral forms

- to complex forms of living

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6
Q

Define adaptive evolution

A
  • common ancestor
  • evolve into several diff species
  • each adapted to particular environment niche
  • e.g. Galapagos finches
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7
Q

Darwin’s observations of finches

A
  • reproduce rapidly, compete for food
  • variations occurred, diff finches with diff beaks suited for particular diet on island
  • selected for by environment
  • those selected survived, reproduced successfully
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8
Q

Mechanism of evolution

A
  1. organisms reproduce rapidly due to abundant food supply
  2. migrate to diff environments
  3. spontaneous mutation occurs, result in variation
    3a. favourable traits granted selective advantage, such organisms survive, reproduce, pass onto next gen
  4. these organisms become predominant species in environment
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9
Q

Artificial selection

A
  • plants and animals with favourable traits

- artificially selected thru selective breeding

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10
Q

How they occur (Natural vs artificial)

A

N: mutations in gene, brought abt by changes in environment
A: manipulation by humans (selective breeding) , humans select organisms with desired traits to reproduce

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11
Q

Speed of process (Natural vs artificial)

A
  • N: v slow

- A: relatively faster

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12
Q

Effects on man (Natural vs artificial)

A
  • N: may be advantageous or harmful

- A: advantageous

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