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biology > natural selection and genetic modification > Flashcards

natural selection and genetic modification Flashcards

1
Q

what does natural selection mean

A

survival of the fittest

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2
Q

what is evolution

A

the slow and continuous change of organisms from one generation to the next

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3
Q

who came up with the theory on natural selection and evolution

A

Charles Darwin

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4
Q

what does bacteria provide

A

evidence for evolution

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5
Q

what happens to species which can’t compete

A

most likely to die out, go extinct

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6
Q

what is antibiotic resistance / how does it happen and get spread

A

when bacteria becomes resistant and less effected by a particular antibiotic, the allele is passed on to lots of the offspring - spread becomes natural.

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7
Q

how does antibiotic resistance show evidence of evolution

A

makes the bacteria better adapted to an environment in which antibiotics are present, more common over time

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8
Q

how do fossils provide evidence for evolution

A

By arranging fossils in chronological (date) order, gradual changes in organisms can be observed.

This provides evidence for evolution, because it shows how species have changed and developed over billions of years.

The lower the fossil in the ground, the older the fossil

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9
Q

what is a fossil

A

any trace of an animal or plant that lived a long time ago

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10
Q

who were the 2 people who came up with the theory of evolution by natural selection

A

Charles Darwin and Wallace

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11
Q

how did Darwin come up with the theory of evolution by natural selection

A

he travelled round on a trip studying plants and animals, he noticed variation in members of the same species and that those with characteristics most suited to the environment were more likely to survive, he also noticed it can be passed on.

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12
Q

how did Wallace contribute come up with the theory of evolution by natural selection

A

he provided lots of evidence to help support the theory of evolution, such as warning colours for animals have been inherited which can help them survive.

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13
Q

3 ideas about evolution which have been influenced by modern biology

A
  1. theory is still relevant today - helps to understand areas of biology
  2. all life changes happen through evolution, everything descends from an ancestor
  3. affects lots of areas of bio including
    - classification
    - antibiotic resistance
    - conservation
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14
Q

classification

A

if all living organisms have descended from a common ancestor, then we’re all related in some way.
We now classify organisms based on how closely related they are.

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15
Q

antibiotic resistance

A

we now understand the importance of finishing the course of drugs to prevent resistant bacteria spreading and we know we need to constantly develop, new antibiotics to fight newly evolved resistant bacteria.

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16
Q

conservation

A

we now understand the importance of genetic diversity and how it helps populations adapt to changing environments.
This has led to conservation projects to protect species.

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17
Q

how do fossils give us clues about what human ancestors

A

Human beings and their ancestors are known as hominids. Fossils of several different hominid species have been found. These fossils have characteristios that are between apes and humans by looking at hominid fossils you can see how humans have evolved over time.

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18
Q

facts about ‘Ardi’

A
  1. a fossil species called ‘Ardipithecus Ramidus’
  2. found 4.4 million years ago
  3. feet structures showed she climbed trees
  4. brain size is the same as a chimpanzee
  5. walked upright, didn’t use her hands to walk
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19
Q

facts about ‘Lucy’

A
  1. fossil species called ‘Australopithecus Afarensis’
  2. found 3.2 million years ago
  3. more human like than Ardi
  4. arched feet, walls more adapted
  5. walked upright, more efficient than Ardi.
  6. brain was slightly larger
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20
Q

leakey’s fossil hominids facts

A
  1. Leakey found ‘Turkana Boy’ a 1.6 million years ago (homo erectus)
  2. more like human than ‘Lucy’
  3. short arms and long legs more human than apes
  4. brain size is larger than Lucy’s (similar to humans)
  5. better adapted to walking upright
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21
Q

how can we show human evolution

A

on a timeline

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22
Q

how can stone tools provide evidence for human evolution

A

species evolved from evolution, you can tell they started using stone tools and these gradually become more complex, brains must be getting larger

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23
Q

what kind of stone tools did Homo Habilis use

A

simple stone tools by hitting pebbles together to make sharp flakes

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24
Q

what kind of stone tools did Homo Erectus use

A

sculpted rocks into shapes to produce more complex tools like simple hand axes

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25
Q

what kind of stone tools did Homo Neanderthalensis use

A

More complex tools

26
Q

what kind of stone tools did Homo Sapiens use

A

flint tools widely used, pointed tools

27
Q

what we stone tools used for

A

hunt, dig, chop, scrape meat, crack bones

28
Q

how can you work out how old a stone tool is

A
  1. structural features
  2. study of rock layers, stratigraphy
  3. carbon dating
29
Q

what is the pendaactyl limb and how does it provide evidence for evolution

A

a limb with 5 digits, similar bone structures usually a different function

the similarity in bone structure says the pednactyl limb has likely been evolved from a common ancestor, if the ancestors were different they would have different bone structures

30
Q

what is classification

A

organising living organisms into groups

31
Q

what are the 5 groups called

A
  1. animals
  2. plants
  3. fungi
  4. prokaryotes
  5. protists
32
Q

examples of animals

A

fish, mammals, reptiles

33
Q

examples of plants

A

grasses, trees

34
Q

examples of fungi

A

mushrooms, toadstools, yeast, mold

35
Q

examples of prokaryotes

A

single celled organisms without a nucleus

36
Q

examples of protists

A

eukaryotic single celled organisms, e.g. algae

37
Q

what are the kingdoms

A
  1. phylum
  2. class
  3. order
  4. family
  5. genus
  6. species
38
Q

how has classification systems changed over time

A

technology shows it’s out of date, biochemical processes and genetics understanding has increased, led to rethink of classification system

39
Q

what did woese suggest

A

should be divided into three large groups called domains

40
Q

archaea

A

Organisms in this domain look similar to bacteria but are actually quite different - as differences in their DNA and RNA sequences show.

They were first found in extreme places such as hot springs and salt lakes

41
Q

bacteria

A

This domain contains true bacteria like E. coli and Staphylococcus.

42
Q

eukarya

A

This domain includes a broad range of organisms including fungi, plants, animals and protists.

43
Q

what is selective breeding

A

when humans artificially select the plants or animals that are going to breed so that genes for particular characteristics remain in the population

44
Q

why are organisms selectively bred

A

to develop useful or attractive features

e.g. to produce more meat or milk or become disease resistant

45
Q

how to selective breed

A

1) From your existing stock select the ones which have the characteristios you’re after.

2) Breed them with each other.

3) Select the best of the offspring, and breed them together.

4) Continue this process over several generations, and the desirable trait gets stronger and stronger.
Eventually, all the offspring will have the characteristic.

46
Q

why is selective breeding important (2)

A

IMPORTANT IN AGRICULTURE
genetic variation means some cattle will have better characteristics for producing meat than others.

USED IN MEDICAL RESEARCH
studied differences in different types of behaviour and the way there brains work

47
Q

what are the 3 disadvantages of selective breeding

A
  1. reduces the gene pool, number of different alleles, same ‘beet animals’ are used, all closely related and known as inbreeding
  2. can cause health problems as well as more chance of inheriting harmful genetic defects during inbreeding when the gene pool is limited.
  3. serious problem if a new disease appears, with less variation, less chance of resistant alleles being present as well as if they’re all the same they can all be wiped out, causing problems to the population
48
Q

what is tissue culture

A

by taking little bits of tissues and growing them, scientists are able to reproduce tissue from a
single individual - so they don’t have to go through the lengthy process of selective breeding.

49
Q

how can plants be grown using tissue culture

A
  1. choose a plant based on its characteristics
  2. remove several pieces of tissue from the parent plant, you get the best results
  3. grow the tissue in a growth medium containing nutrients and growth hormones
  4. this is done under aseptic conditions to prevent growth of microbes which can harm the plants
  5. as the tissue produce shoots and roots they can be moved to plotting compost to carry on growing
50
Q

how can animal tissues be useful for medical research

A

often used in medical research as it means you can carry out experiments on tissue in isolation

  1. First, a sample of the tissue you want to study, e.g. tissue from the pancreas, is extracted from the animal.
  2. The cells in the sample are separated from each other using enzymes.
  3. Then they are placed in a culture vessel and bathed 0% in a growth medium containing all the nutrients that they need. This allows them to grow and multiply.
  4. After several rounds of cell division, the cells can be split up again and placed into separate vessels to encourage further growth.
  5. Once the tissue culture has been grown, it can be stored for future use.
51
Q

how does genetic engineering work

A
  1. the DNA you want to insert (e.g. the gene for human insulin) is cut out with a restriction enzyme. the vector DNA is then cut open using the same restriction enzyme
  2. the vector DNA and the DNA you inserting are left with sticky ends. they are mixed together with ligase enzymes
  3. the ligases join the pieces of DNA together to make recombinant DNA.
  4. the recombinant DNA is inserted into other cells
  5. these cells can now use the gene you inserted to make the protein you want
52
Q

restriction enzyme

A

recognise specific sequences of DNA and cut the DNA at these points - the pieces of DNA are left with sticky ends where they have been cut.

53
Q

ligase

A

enzymes are used to join two pieces of DNA together at their sticky ends.

54
Q

recombinant DNA

A

Two different bits of DNA stuck together

55
Q

why is genetic engineering useful in agriculture and medicine (2)

A
  1. can be genetically modified to resist herbicides
  2. engineer bacteria to produce human insulin
56
Q

genetic engineering concerns

A
  1. hard to predict effects of modifying someone’s genome - could have health problems down the line
  2. could modify and affect food chains or human health
  3. transplanted genes may get out into the environment and affect other plant types which would be a problem
57
Q

what can GMOs do

A

provide food for many people who might suffer from hunger

58
Q

why can crops be genetically modified

A

makes them resistant to insect pests, improve crop yields and reduce the need for chemical pesticides

59
Q

how do they develop and stop developing resistance

A

if they are consistently exposed, they can develop a resistance and no longer be killed by things, farmers avoid this by using other insecticides too

60
Q

how do GMOs increase food production

A

crops that are genetically engineered to be resistant to pests or to grow better in drought conditions can help to improve crop yields, increasing food production down the line

61
Q

why is GMOs increase food production a bad idea

A
  1. can’t afford to buy food, need to tackle poverty first
  2. countries may become dependent on companies who sell GM seeds
  3. poor soil is the reason why crops fail, GM crops won’t survive
62
Q

what other techniques can increase food production

A
  1. soils are poor, applying fertilisers is likely the best way to increase yields
  2. pests can be controlled without the use of GM crops or chemical pesticides, biological control
  3. biological control is less harmful to wildlife

biology (9 decks)

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