3.4.4 - Genetic diversity and adaptation Flashcards

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1
Q

Define genetic diversity - explain how genetic diversity enables natural selection

A

the number of different alleles of genes in a population - enables natural selection to occur - more genetic diversity = more likely some individuals in the population will survive environmental change

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2
Q

Explain how reproductive success impacts allele frequency in a gene pool ?

A
  1. gene pool contains a large frequency of alleles
    2.** random mutations result in new alleles **of a gene
  2. depending on the environment this could be beneficial - individuals more likely to outcompete others for resources
  3. higher chance of successfully reproducing and passing alleles to the next generation -** so advantageous allele is most likely to be passed on**
  4. over many generations the number of individuals with the advantageous allele will increase -** increases in frequency**
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3
Q

Define selection

A

organisms that are best adapted to their environment will survive and breed - different environmental conditions favour different characteristics

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4
Q

Define directional selection

A

favours individuals at the extremes (phenotype at one extreme is selected for)
- changes the overall characteristics of the population
- occurs when environmental conditions change

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5
Q

Define stabilising selection

A

favours average individuals (phenotypes around the mean are selected for and those at both extremes are selected against)
- preserves characteristics of the population
- occurs when environmental conditions remain stable

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6
Q

How do bacteria show directional selection?

A
  1. mutation occurs in the allele of a bacteria - new protein is able to break down the antibiotic penicilin
    2.** bacteria with the mutation is able to survive** while the rest die
  2. bacteria divides by** binary fission **- more resistant bacteria
  3. frequency of the mutated allele increased
  4. **normal distribution shifted **in the direction of increased penicilin resistance
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7
Q

Give three types of adaptations an organism can aquire to increase chances of survival

A
  • anatomical
  • physiological
  • behavioural
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