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Biology > Unit 4 - Natural Selection And Genetic Modification > Flashcards

Unit 4 - Natural Selection And Genetic Modification Flashcards

1
Q

What is evolution

A

To gradual change in characteristics of a species over time

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2
Q

Why do you fossils is not show smooth changes over time

A

Because not all have been discovered

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3
Q

What is the name of the most complete set of fossils

A

Ardi

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4
Q

What species is Ardi from

A

Ardipithecus ramidus

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5
Q

Give three characteristics of Ardi

A

About 1.2 m tall, very long arms, may have been able to walk right

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6
Q

What species is Lucy

A

Australopithecus afarensis

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7
Q

What is the species name for modern humans

A

Homo sapiens

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8
Q

What species did Homo sapiens evolve from

A

Homo neanderthalensis

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9
Q

How can scientists work out the ages of stone tools

A

Using the different layers of rock. The stone tool is about the same age as the layer of rock

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10
Q

What could the oldest stone tools be used for

A

Skinning an animal or cutting up meat

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11
Q

Which two scientists came up with the idea of evolution

A

Charles Darwin and Alfred Russell Wallace

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12
Q

What does genetic variation mean

A

When the characteristics of individuals vary

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13
Q

What is environmental change

A

When conditions in an area change. For example, the lack of resaws such as food

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14
Q

What is natural selection

A

Sometimes the variations of some individuals make them better at coping with changes and are more likely to survive

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15
Q

How does evolution happen

A

If the environmental conditions remain changed, natural selection occurs over and over again, and a new species evolve with all the individuals having the better adapted variations

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16
Q

Given examples of how a species could have evolved

A

The environment could be getting cold so for some animals who may have been hairier would have survived against the cold. These animals would have bred and overtime the animals became hairier and hairier forming a new species

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17
Q

What was warfarin used for

A

Poison rats

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18
Q

How did the rats become resistant to warfarin

A

Due to genetic variation they had always been rats that were resistant. As the poison killed the non-resistant, the only ones left to breed were resistant

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19
Q

Give two examples where species had become resistant to poisons

A

Rats to warfarin and bacteria to antibiotics

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20
Q

How can stopping an antibiotic early develop a species resistant to the antibiotic

A

Some bacteria would be more resistant to the antibiotic. When the antibiotic course is started, the less resistant bacteria are killed. If the course is finished early, the more resistant bacteria would still be alive and would also breed. This creates a new population of bacteria that are resistant to the antibiotic

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21
Q

Why did scientists used to think that the Earth species could not evolve

A

They thought that God had created all of species and their characteristics could not change

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22
Q

How did Darwin begin to think about evolution

A

He noticed differences between mockingbirds on different islands and wondered whether a species could change form if it moved into a different area

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23
Q

What explanation did Darwin have for evolution

A

Organisms normally produce more of offspring than what could survive. Only the individuals best suited to the surroundings would survive and reproduce to pass on their characteristics

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24
Q

What organisms had Wallace studied

A

The tiger beatles, he noticed that in Indonesia they were different colours depending on where they live to camouflage them. Natural selection allowed him to explain it

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25
Q

What is a pentadactyl limb

A

A limb with five fingers

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26
Q

What does the pentadactyl limb suggest

A

There was evolution from a common ancestor and not that all bones were designed for specific purposes independently of one another

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27
Q

What is classification

A

Dividing organisms into groups based on what they look like

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28
Q

What the 5 kingdoms

A

Animals, plants, fungi, protists and prokaryotes

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29
Q

What does the last group contain of classification

A

One type of organism

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30
Q

How did Lennaeus give each organism binomial name

A

Using the two last groups, genus and species

31
Q

Why might there be problems using characteristics for classification

A

Some organisms have evolved similar characteristics but are not closely related

32
Q

How did modern scientist alter the classification system

A

They made it so that the smaller groups contained organisms that have evolved from recent common ancestors

33
Q

What is Archaea?

A

A group found in the prokaryote kingdom where the organisms are single celled that have no nuclei

34
Q

What is the three domain system of classification

A

This was created by call roads and all organisms should be divided into archaea bacteria, eukarya.

35
Q

How can you tell how closely related organisms are

A

The more DNA two organisms have in common, the more recently they evolved from a common ancestor so the more closely related they are

36
Q

What is natural selection

A

When by chance, some individuals inherit characteristics that allows them to survive better than others in a certain area

37
Q

What is artificial selection

A

When humans choose organisms because they have useful characteristics, such as sheep with thick wool

38
Q

What is selective breeding

A

When people bred organisms that have useful characteristics to humans. This results in offsprings that inherit the characteristics so by repeating this process, you would eventually get organisms with the most useful characteristics

39
Q

What is selective breeding used today for

A

To produce new breeds of animals and new varieties of plants species

40
Q

Give two examples of how people have used selective breeding

A

When farmers selectively bred wild wheat plants. When people selectively bred hairier sheep

41
Q

Give five reasons why plants and animals are often selectively bred

A

Disease resistance, yield (quantity), coping with certain environmental conditions, fast growth, flavour

42
Q

What is genetic engineering

A

Changing the DNA of an organism, it’s genome, often by inserting genes from another which creates genetically modified organisms

43
Q

Give a positive and negative of genetic engineering compared to selective breeding

A

Positive: much faster
Negative: much more expensive

44
Q

Give an example of a GMO and why it is useful to humans

A

Golden rice which has two jeans inserted into it Gino, one from a daffodil and one from a bacteria. It makes the rice produce beta-carotene in its grains. This makes vitamin A to stop the cause of blindness

45
Q

Why are GMO is used today

A

Resistant to disease causing organisms
In goats and sheep, to produce proteins in their milk that can treat human diseases
GM pigs with human like organs to use in organ transplants
Salmon that grow much faster

46
Q

What is tissue culture

A

The growing of cells all tissues in a liquid containing nutrients or on a solid medium

47
Q

What is a callus

A

A clump of undifferentiated cells

48
Q

What is tissue culture used for

A

To produce new plants of very rare species which are at risk of extinction
To produce new individuals of plant species that may be difficult to grow from seed
To produce clones of GM plants

49
Q

Why are some undifferentiated cells in a callus treated

A

To make them differentiate, to become specialised

50
Q

Give the steps of tissue culture

A

A piece of plant in placed in bleach solution to sterilise it
Only a few cells are cut off and placed on sterile nutrient medium to grow into a callus
The callus is treated with hormones so that the plantlets develop with shoots and roots
The plantlets are separated and grown on nutrient medium in sterile conditions
When the plants are large enough they are planted into soil or compost

51
Q

Why is tissue culture used in medicine

A

Cutting a thin-layer of cells makes it easier to study how the cells communicate with each other
To study for viruses which cannot replicate outside of cells
To study how cancer spreads
How infected cells respond to new medicines without receiving harm to animals or humans

52
Q

What are alleles

A

The different forms of genes

53
Q

What happens to alleles during selective breeding

A

Certain alleles are selected however others become rare or disappear. This means that alleles that might be useful in the future are no longer available

54
Q

Give some negatives of selective breeding

A

If a change in a condition occurs, all organisms are affected. For example a new disease
Animal welfare. For example some selectively bred chickens produce so much breast meat they can hardly stand up

55
Q

Why have GM crops been produced

A

To be resistant to some insects so less insecticide is needed
To be resistant to certain herbicides so it kills weeds but not the crop

56
Q

What might happen if GM plants reproduce with wild plant varieties

A

The genes may have unknown consequences in wild plants

57
Q

State a benefit of golden rice

A

It produces vitamin a which helps with the cause of blindness

58
Q

Why might GM bacteria be produced

A

To produce useful substances such as insulin

59
Q

Give a positive and negative about insulin produced by GM bacteria

A

It is cheaper and suitable for vegans or religious people

It is slightly different to insulin from mammals so not all diabetics can use it

60
Q

State the process of genetic engineering of bacteria

A

Restriction enzymes makes staggered cuts in DNA molecules, containing the gene, producing sections with a few unpaired bases at each end called sticky ends
Restriction enzymes also cut plasmids in the same way so they also have sticky ends
The sections of DNA or mixed with the cut plasmids. The complimentary bases on the sticky ends are paired up and an enzyme called ligase is you used to join the ends together
The plasmids are inserted back into bacteria which of then grown in huge tanks

61
Q

What are plasmids

A

Small circles of DNA found in a bacterium

62
Q

What is recombinant DNA

A

When DNA is combined in a new way

63
Q

What is a vector

A

A DNA molecule used to carry new DNA into another cell

64
Q

What is the yield

A

The amount of the crop we can use

65
Q

What is Bt toxin

A

A natural insecticide protein

66
Q

Give an advantage of GM Bt toxin

A

It only affects insects that chew on the plant tissues so insect predators are not harmed for example ladybirds

67
Q

Why might other pests not be affected by Bt toxin

A

Aphids suck sap from the plant but do not chew the plant tissue

68
Q

Why is having different varieties of Bt toxin bacteria a positive

A

When the pests develop resistance to the toxin the GM crop plants can be developed in the new varieties

69
Q

What is biological control

A

Using organisms to control pests

70
Q

Give an example of biological control

A

Using Weaver and nests as they remove some insect pests

71
Q

What are fertilisers

A

Chemical compounds use to increase food production

72
Q

How can pollution be caused by fertilisers

A

If not all of the fertiliser is absorbed by a crop some make it into a nearby stream, lake or river

73
Q

What impact can water pollution have on other organisms

A

It can lead to the death of organisms in the water and also cause health problems for humans and animals if they drink the water

Biology (9 decks)

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