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Biology GCSE > Topic 4 - Natural Selection and Genetic Modification > Flashcards

Topic 4 - Natural Selection and Genetic Modification Flashcards

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1
Q

evolution

A

gradual change in the characteristics of a species over time

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2
Q

natural selection

A

by chance the variations of some individuals make them better at coping with the change than others (survival of the fittest)

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3
Q

what’s a piece of evidence that shows human evolution

A
  • fossils
  • stone tools
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4
Q

how can you tell how old a stone tool is

A

the older stone tools would be more simple (more worn down) and the more recent stones would be more sophisticated

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5
Q

genetic variation

A

the characteristics of individuals vary due to differences in genes

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6
Q

environmental change

A

conditions in an area change
e.g. lack of food causes more competition between organisms

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7
Q

inheritance

A

the survivors breed and pass on their variations to their offspring

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8
Q

common ancestor

A

when one species is the ancestor of two or more species

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9
Q

three reasons why the theory of evolution by means of natural selection was slow to be accepted

A
  • lack of supporting evidence
  • limited scientific understanding of genetics and inheritance
  • conflicting religious beliefs (challenge in correction stories from bible)
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10
Q

what two scientists helped with developing the theory of evolution

A

Charles Darwin and Alfred Wallace

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11
Q

antibiotic resistance

A

happens when germs like bacteria and fungi develop the ability to defeat the drugs designed to kill them

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12
Q

what causes antibiotic resistance

A

when you take antibiotics the least resistant bacteria is killed however some bacteria (the more resistant) survives and start to spread making more bacteria resistant

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13
Q

how did the rats become resistant to warfarin

A
  • due to genetic variation caused by mutations, there were some rats in the population that survived the poison - the majority of the rats would’ve died
  • these resistant individuals were able to survive
  • they then bred with other survivors and had offspring with similar features
  • this process occurred over many generations until the only individuals and the population were the warfarin resistant individuals
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14
Q

why did the warfarin not cause the rats to become resistant

A
  • because the warfarin provided the environment for natural selection to occur within
  • only the rats with beneficial random mutations are able to survive when they eat the poison
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15
Q

pentadactyl limb

A

vertebrates have limbs with 5 fingers

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16
Q

pentadactyl limb theory

A

the limb similarity suggest evolution from a common ancestor

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17
Q

classification system

A

dividing organisms into groups based on what they look like

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18
Q

name the kingdoms of classification

A

animals, plants, fungi, protists, prokaryotes

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19
Q

what happens in selective breeding

A
  • you select individuals with desirable characteristics
  • these individuals are bred together
  • they produce offspring with the desirable characteristic
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20
Q

genetic engineering

A

when you change the DNA of an organism (its genome) by inserting genes from another; this creates genetically modified organisms (GMOs)

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21
Q

process of genetic modification in bacteria

A
  • cut out desirable gene using restriction endonuclease enzyme
  • cut out a bit of the plasmid with the same restriction endonuclease enzyme
  • this cutting leave strands of DNA with jaggered ends called sticky ends
  • the desirable gene is joined in with the plasmid using an enzyme called ligase; this is recombined DNA
  • the plasmid is returned to the bacterial cell
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22
Q

stem cells

A

special cells produced by bone marrow

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23
Q

tissue culture

A

is a technique in which tissues of plants or animals are cultured and grown in a laboratory

24
Q

why must everything be sterilised during tissue culture

A

to prevent the growth of microorganisms (e.g. bacteria)

25
Q

what does it mean if something is sterilized

A

to make something completely clean and free from bacteria

26
Q

callus

A

a clump of undifferentiated plant cells

27
Q

name things that plants and animals are often selectively bred for:

A
  • disease resistance (how are they cope with diseases)
  • yield (how much useful product they make)
  • coping with certain environmental conditions
  • fast growth
  • flavour
28
Q

cell culture

A

a collection of techniques and resources in which cells that were part of an organism are growth in an artificial controlled environment

29
Q

ways that cell culturing be useful:

A
  • has many uses in medicine - culturing a thin layer of cells on a solid medium makes it easier to study house sales communicate with each other
  • needed to study viruses
  • cultures of cancer cells have been developed to study how cancer develops and spreads
  • investigate how infected cells respond to new medicines without risking harm to animals or humans
30
Q

why are organisms selectively bred or genetically engineered

A
  • grow faster
  • cope with environmental conditions
  • increase yields
  • make new products
31
Q

biological vector

A

a DNA molecule that is used to carry a particular DNA segment to another cell

32
Q

pesticide

A

a substance used for destroying insects or other organisms harmful to plants or animals

33
Q

insecticide

A

a type of pesticide used to kill insects

34
Q

fungicide

A

a type of pesticide that kills or prevents the growth of fungi and their spores

35
Q

fertilizer

A

natural or artificial substance containing the chemical elements that improve growth and productiveness of plants

36
Q

weed

A

a plane that’s considered undesirable in a particular situation

37
Q

biological control

A

the use by humans beneficial insects, such as predators and parasitoids or pathogens such as fungi and viruses to control unwanted insects, weeds or diseases

38
Q

artificial fertiliser

A

man-made fertiliser

39
Q

herbicide

A

a substance that is toxic to plants, used to destroy unwanted weeds

40
Q

organic farming

A

no use of artificial fertilisers, no pesticide and no medicine (all natural)

41
Q

advantages of using genetic modification

A
  • simpler to grow
  • use fewer chemicals
42
Q

disadvantages of using genetic modification

A
  • harm to human or animal health
  • cross-contamination
43
Q

advantages of selective breeding

A
  • expand inherited potential
  • particular characteristic to help increase crop yield
44
Q

disadvantages of selective breeding

A
  • lack of genetic diversity in alleles a crop - future crop scientists have less alleles to develop varieties in the future
45
Q

process of genetic engineering

A
  • cut out a desirable gene with a desirable characteristic from one organism
  • transfer the gene to a different organism
  • the other organism now has the desirable characteristic
  • this produces a genetically modified organism (GMO)
46
Q

genetic engineering

A

modifying an organisms genome

47
Q

negatives of selective breeding

A
  • genes exist in different forms called alleles which cause variation in different characteristics so only certain alleles are selected others become rare or disappear so alleles that might be useful in the future are no longer available
  • When farming with a huge numbers of the same breed they are very similar so for changing conditions if it affects one organism all the others are affected
  • animal welfare - e.g. Some selectively bread chickens produce so much breast meat they can hardly stand up
48
Q

Genetic engineering issues

A
  • if GM cross reproduce with wild plant varieties and pass on their resistant genes, these genes may have unknown consequences in wild plants
  • People think that eating GM organisms may be bad for health
49
Q

How to genetically engineer bacteria

A
  • scientist use restriction enzymes to cut useful gene of an organism DNA
  • This cutting these strands of DNA with jagged end with ‘sticky ends’ (unpaired bases at each end)
  • The new section of DNA is inserted into the plasmid
  • if the two sticky ends match, they can be joined together using an enzyme called ligase
50
Q

advantages of making insulin using genetically modified bacteria rather than extracting it from animals

A
  • Cheaper
  • suitable for vegans or people who do not eat pork or beef for religious reasons
51
Q

what is BT toxin?

A

Natural insecticide protein

52
Q

Explain why using an insect resistance variety of genetically modified plants might be better for the environment than spraying non genetically modified plants with insecticide

A

Because it only affects insects that bite into the plant tissues so insect predators such as ladybird and spiders aren’t harmed
—> less animals are killed innocently

53
Q

how does adding fertiliser affect the yield of crop plants?

A
  • Help increase the gross and yield of crop plants because it contains mineral irons that plants absorb from the soil to make healthy new cells
54
Q

explain the theory of evolution by natural selection

A
  • there is variation within the species due to genetic mutations which make some organisms have certain characteristics that make them more likely to survive than others
  • therefore there is a struggle for existence so adapted organisms survive and unadapted organisms die (‘survival of the fittest’)
  • this leads to the offspring inheriting the characteristics needed to survive
  • this is repeated over generations
55
Q

why is having feathers that are less brightly coloured increase the survival rate of birds

A

would be less noticeable as they are camouflaged and therefore are less likely to be eaten by predators

56
Q

why is more important for the survival of the species that survival rate is higher in female birds than male birds

A

females can reproduce however males can reproduce with multiple female birds

Biology GCSE (8 decks)

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