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

Topic 4 - Natural Selection and Genetic Modification Flashcards

(78 cards)

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1
Q

What does natural selection mean?

A

Survival of the Fittest

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2
Q

Why do individuals in a population show genetic variation?

A

Because of differences in their alleles

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3
Q

How do new alleles arise?

A

Mutations

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4
Q

What are examples of selection pressures

A

Predation
Competition
Disease

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5
Q

What do selection pressures do?

A

Affect an organisms chance of surviving and reproducing

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6
Q

Why do selection pressures lea to survival of the fittest?

A

The organisms with the characteristics that make them better adapted will be more likely to survive and breed - passing on its gene

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7
Q

How many organisms mutate?

A

Every SINGLE organism

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8
Q

How does a bacterial population become resistant to a particular antibiotic?

A

Antibiotic administered, bacteria without resistance allele die faster, but the bacteria with the allele are more likely to survive and therefore reproduce passing on its resistant allele.
This continues increasing the abundance of the allele within the population

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9
Q

How does antibiotic resistance provide evidence for evolution?

A

It shows organisms slowly becoming better adapted to an environment

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10
Q

What is a fossil?

A

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

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11
Q

How do fossils provide evidence for evolution?

A

If chronologically ordered, gradual changes can be observed showing species change and develop over billions of years

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12
Q

What did Darwin notice?

A

There was variation in members of the same species

Organisms more suited to the environment were more likely to survive

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13
Q

What does evolution suggest?

A

We have all descended from a common ancestor

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14
Q

What are human beings and ancestors known as?

A

Hominids

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15
Q

When was Ardi around?

A

4.4 million years ago

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16
Q

Describe the features of Ardi?

A

Tree feet
Long arms but short legs
Small brain
Walked upright

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17
Q

When was lucy alive?

A

3.2 million years ago

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18
Q

Describe Lucy’s features?

A

Arched feed (less climbinb)
Arms and legs crossbreed of apes and humans
Small but larger brain than Ardi
Walked upright

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19
Q

How old were the fossils Leakey found?

A

1.6 million years old

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20
Q

What did Leakey find?

A

Homo erectus skeleton that had short arms and long legs

Brain size of ours

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21
Q

List the order of fossils? (Lucy, Ardi and Turkana Boy)

A

Ardi
Lucy
Tukana Boy

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22
Q

Outline the major changes observed between the fossils of Ardi and Lucy?

A

Lucy’s feet were more arched than Ardi’s
Lucy had n ape-like big toe unlike Ardi
Lucy had a larger brain than Ardi

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23
Q

Describe Wallace’s role in developing the theory of evolution by natural selection?

A

Wallace provided evidence for natural selection and worked with Darwin to develop the theory

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24
Q

How does the development of stone tools provide evidence for evolution?

A

As tools become more complex, our brains must of been getting larger

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25
How do we tell how old a tool is?
Complexity (simpler likely to be older) Stratigraphy (level of rock it was found, deeper more likely to be older) Carbon dating
26
Why can't wood tools be found?
Because they have rotted away
27
What is a species?
A group of organisms that will reproduce to produce a fertile offspring
28
What are the advantages of standing up for apes?
Back isnt exposed to sun as much, so less energy spent cooling
29
Suggest why tools are often found on their own?
The organism using it is likely to of rotted away
30
What is a pentadactyl limb?
A limb with five digits
31
How do pentadactyl limbs provide evidence for evolution?
Because many species have similar bone structures it could be suggested we all have evolved from a common ancestor
32
Why do pentadactyl limbs disprove we all had different ancestors?
Because it'd be highly unlikely that we would share a similar bone structure
33
State one method a scientist could use to find the age of a stone tool?
Stratigraphy | Carbon-14 dating
34
A scientist found a pointed stone tool among bones | What does the shape of the tool suggest about the fossils?
They belong to more recent species
35
How were organisms originally classified?
Based on observable characteristics
36
What are protists?
Eukaryotic single-celled organisms
37
What is the domain classification based off?
The genome of the species rather than their observable characteristics
38
What is selective breeding?
When humans artificially select organisms that are going to breed so that the genes for particular characteristics remain in the population
39
Give examples of selective breeding in action?
Animals with more meat or milk Crops with disease resistance Dogs with a gentle temperament Plants that produce bigger fruit
40
How do you do selective breeding?
Select the organisms with the characteristics and breed them Select the best of the offspring and then breed them together Continue this process and the trait will get stronger and stronger
41
What is the main disadvantage to selective breeding?
Reduces the gene pool
42
What is the problem with reducing the gene pool?
Leads to inbreeding
43
What does inbreeding lead to?
Health problems as theres more chance of harmful genetic defects (build up of recessive alleles) Lack of protection against disease as less chance of resistance alleles being present
44
Give three potential downsides selective breeding can cause?
Lack of protection against disease Health problems (build up of recessive alleles Ethical issues
45
What does tissue culture involve>
Growing cells on an artificial growth mediu
46
What are the advantages of growing whole plants using tissue culture?
Quick Requires little space All the time
47
What are all the cells produced via tissue culture?
Clones
48
Whats the advantage of tissues from tissue culture being clones?
Same beneficial features or If testing on, provides a control
49
How do you grow tissues?
Choose the plant you want to clone Remove several small pieces of tissue (best if fast-growing roots/shoots) Grow the tissue in growth medium in aseptic conditions When shoots and roots produced, can be moved to potting compost
50
What is the growth medium made of?
Nutrients and growth hormones
51
Why is tissue culture done in aseptic conditions?
To prevent the growth of microbes that could harm the plant
52
What is the advantage of testing on animal tissue?
Means you can use medicine on tissues in isolation (experiment without complications from other processes)
53
How do you undergo animal cell tissue culture?
Extract a sample of the tissue Separate the cells in the sample using enzymes Place it in a culture vessel and bath it in a growth medium allowing them to grow and multiply Leave to divide, split up and place in separate vessels to encourage further growth
54
How are the cells in animal tissue culture separated?
Using enzymes
55
Why are the cells in animal tissues placed in growth medium?
As medium contains nutrients it allows them to grow and multiply
56
Why are the cells in animal tissue culture placed into separate vessels?
To encourage further growth
57
What do restriction enzymes do?
Recognise specific sequences of DNA and cut it out, leaving sticky ends
58
What are sticky ends?
The ends of DNA that has been cut
59
What enzymes are used to join two pieces of DNA together?
Ligase
60
WHat is recombinant DNA?
Two DIFFERENT bits of DNA stuck together
61
What is a vector?
Something that's used to transfer DNA into a cell
62
What are plasmids?
Small, circular molecules of DNA that can be transferred between bacteria
63
How do viruses act as vectors?
They insert DNA into the organisms they infect
64
How do you undergo genetic engineering?
Cut the DNA you want to insert with a restriction enzyme and cut the vector DNA using the SAME restriction enzyme As both DNA's left with sticky ends, join together with ligase enzymes forming recombinant DNA The recombinant DNA n the vector is inserted into other cells causing these cells to have the gene you inserted to make the protein you want
65
What must you do when cutting the DNA of the cell and the vector?
Use the SAME restriction enzyme
66
How does the cut DNA and the vector DNA join together?
The ligase enzymes let them join at their sticky ends
67
How is genetic engineering useful?
Can modify crops to be resistant to herbicides | Can modify bacteria to produce useful proteins and substances for humans and animals
68
What are the problems with genetic engineering?
Hard to predict the effect of modifying genomes Crops may affect the health of animals up the food chain Resistant genes may make it out to other organisms (creating super weeds)
69
How do organisms evolve by the process of natural selection?`
Individuals have varying characteristics A change in the environment (lack of resoruce, increased competition or climate) The variations allow certain individuals better at coping allowing them to survive and breed passing on their variations so new offspring have same characteristics If environment stays changed, a new species will evolve with all the individuals having the better adaptation
70
Describe the rough steps of natural selection?
``` Genetic Variation Environment changes Survival of Fittest Inheritance Evolution... ```
71
Name the areas of modern biology that have been influenced by Darwin and Wallace's theory of evolution?
Classification Antibiotic resitance Conservation (genetic diversity)
72
Which fossil is older - 'Ardi' or 'Lucy'?
Ardi
73
What are hominids?
Human beings and our ancestors
74
How can selective breeding be used to improve yields in the meat industry?
Larger sized cattle can be bred over generations leading to larger yields
75
What is a gene pool?
The number of DIFFERENT alleles in a population
76
Why does selective breeding reduce gene pools?
As 'best animals' bred - all of the population will be closely related, reducing the variation of genes
77
What are restriction enzymes used for in genetic engineering?
Cutting the DNA and allowing it to be mixed with another to form recombinant DNA
78
What is a vector?
An organism that is used to transfer DNA into a cell

Biology GCSE (9 decks)

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