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biology > evolution of species > Flashcards

evolution of species Flashcards

1
Q

what is a species?

A

a group of organisms that can interbreed to produce fertile offspring

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2
Q

what is variation?

A

genetic differences between members of the same species

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3
Q

what does variation aloow?

A

allows species to better adapt to changes in environmental condition

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4
Q

what is a mutation?

A

a random and permanent change to genetic material (DNA)

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5
Q

how does mutation occur?

A

mutation occurs spontaneously and the rate at which mutation can occur can be increased by exposure to environmental factors

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6
Q

what are examples of mutagenic agents?

A
  • harmful chemicals
  • UV light
  • x-rays
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7
Q

what are the three types of mutations?

A
  • advantageous
  • neutral
  • disadvantageous
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8
Q

advantageous mutation

A

beneficial to the survival of the organism

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9
Q

neutral mutation

A

has no effect on the survival of the organism

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10
Q

disadvantageous mutation

A

not beneficial to the survival of the organism

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11
Q

what is the only source of new alleles within a population?

A

mutations

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12
Q

what heps increase variation within a species?

A

introducing new alleles into a gene pool

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13
Q

what does variation make possible?

A

for species to evolve over time

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14
Q

what is an adaptation?

A

inherited characteristics that make an organism well suited to survive within its environment

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15
Q

what are the two types of adaptation?

A
  • structural
  • behavioural
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16
Q

what is structural adaptation?

A

an anatomical feature that helps an organism survive

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17
Q

what is behavioural adaptation?

A

a behavioural response to an environmental stimulus

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18
Q

what adaptations do camels have?

A
  • long legs help to keep the camel cool
  • stores fat in humps helping it to survive long periods without food and water
  • stretchy nostrils and long eyelashes help to keep sand out
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19
Q

what adaptations do polar bears have?

A
  • thick fur to trap heat
  • large amounts of body fat for insulation
  • wide feet to spread their weight over ice and snow
20
Q

what adaptations do cacti have?

A
  • succulent tissues for storage of water
  • spines on leaves protect the cactus from predators
21
Q

what are examples of behavioural adaptation?

A
  • snarling and fighting
  • looking out for danger
  • marking territory with urine
22
Q

what are the two types of behaviour?

A
  • innate behaviour
  • learned behaviour
23
Q

what is innate behaviour?

A

existed from birth or inherited

24
Q

what is learned behaviour?

A

gained from observation or experiences

25
Q

what are examples of innate behaviour?

A
  • hibernation
  • migration
  • courtship
26
Q

hibernation

A
  • animals become dormant in the late autumn
  • onset of behaviour is triggered by shorter days
  • alows the animal to survive exterme winter conditions
27
Q

migration

A
  • animals travel to warmer climates in winter
  • onset of behaviour is triggered by shorter days
  • allows the animal to survive exterme winter conditions
28
Q

courtship

A
  • animals mate during springtime
  • onset of behaviours is triggered by longerdays
  • ensures young are born in suitable conditions
29
Q

what are the selection pressures?

A
  • competition
  • predation
  • disease
  • climate change
30
Q

when does natural selection occur?

A

when selection pressures are present in an environment

31
Q

which individuals survive and reproduce?

A

only the best adapted individuals

32
Q

what does natural selection increase?

A

the frequency of favourable alleles that present a selective advantage within the population

33
Q

what is a selective advantage?

A

inherited characteristics that make an organism well suited to survive within its environment

34
Q

how has evolutionary change by natural selection took place?

A

gradually over millions of years

35
Q

what are superbugs?

A

bacteria that have become resistant to several antibiotics

36
Q

why has antibiotic resistance happened so fast?

A

some species of bacteria can double in number every 20 minutes
mutations spread rapidly through a population

37
Q

what are stages of antibiotic resistance?

A
  1. one mutant bacteria arrives spontaneously within the population
  2. mutant bacteria has a selective advantage to the antibiotic that it is exposed to and survives
  3. mutant bacteria reproduce to make more resistant bacteria
  4. one of these mutant bacteria has a selective advantege to a second antibiotic that it is exposed to and survives
  5. mutant bacteria reproduces to make more resistant bacteria
38
Q

what is speciation?

A

the formation of two or more new species from one common ancestor

39
Q

what are the four stages of speciation?

A
  • isolation
  • mutation
  • natural selection
  • speciation
40
Q

what happens during the isolation stage?

A

original population is separated into two sub-populations by an isolation barrier

41
Q

what are the three types of isolation barriers?

A
  • geographical
  • environmental
  • behavioural
42
Q

what are examples of geographical isolation barriers?

A
  • mountain
  • deserts
  • oceans
  • rivers
43
Q

what are examples of environmental isolation barriers?

A
  • temperature
  • light intensity
  • soil moisture/pH
44
Q

what are examples of behavioural isolation barriers?

A
  • mating rituals
  • time of breeding
45
Q

what happens during the mutation stage?

A

random mutations arrive within each sub-population which increases variation between organisms

46
Q

what happens during the natural selection stage?

A

each sub-population is exposed to different selection pressures
only organisms with a selective advantage survive and reproduce

47
Q

what happens during the speciation stage?

A

the gene pool of each sub-population changes over many generations
the organisms become so genetically different that they can no longer interbreed to produce fertile offspring

biology (24 decks)

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