B14 - Variation and Evolution Flashcards

1
Q

Variation?

A

the differences in the characteristics of individuals in a population

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2
Q

Phenotype?

A

physical characteristics

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3
Q

What is variation caused by? (3)

A
  • differences in genes inherited (genetic causes)
  • the conditions in which the organisms develop (environmental causes)
  • or a combination of both
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4
Q

Theory of evolution by natural selection?

A

all species of living things have evolved from simple life forms that first developed over 3 billion years ago

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5
Q

Key steps in natural selection?

A

mutation of gene –> advantage to survival –> breed –> pass on genes

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6
Q

Very rarely do mutations lead to a new…

A

phenotype

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7
Q

D. Selective breeding?

A

speeds up natural selection by selecting animals or plants for breeding that have a required characteristic

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8
Q

Desired characteristics for selective breeding?

A

disease resistance
increased food production
domestic dogs with a gentle nature
heavily scented flowers

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9
Q

Problems with selective breeding?

A
  • reduces number of alleles in population
  • lack of variation could lead to whole population being wiped out if conditions change
  • inbreeding - some breeds are prone to inherited defects or certain diseases or
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10
Q

Genetic engineering?

A

genes transferred to the cells of animals and plants at an early stage of development so they develop desired characteristics

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11
Q

Process of genetic engineering?

A
  • genes from chromosomes of organisms ‘cut out’ by enzymes

- transferred o the cells of bacteria and other organisms using a vector ( usually bacteria plasmid or virus)

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12
Q

Genetically modified crops also known as…

A

GM crops

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13
Q

GM crops usually have…

A

improved resistance to insect attacks or herbicides and have a higher yield

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14
Q

Examples of GM crops? (3)

A
  • potatoes modified to have more starch
  • soybeans modified to produce healthier balance of fatty acids
  • some GM grasses absorb and break down explosive residue in soil
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15
Q

Benefits of genetic engineering in agriculture? (3)

A
  • improved growth rate in plants and animals
  • crops can be designed to grow well in hot/cold/dry parts of the world
  • increased food value of crops as GM crops usually have much bigger yields
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