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Biology > B4 Natural Selection and Genetic Modification > Flashcards

B4 Natural Selection and Genetic Modification Flashcards

1
Q

Define

evolution.

A

the gradual change in the characteristics of a species over time

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2
Q

What is a

cladogram?

A

a tree diagram showing the evolutionary relationships and common ancestors

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3
Q

What are

nodes?

(on cladograms)

A

branching points which indicate a speciation event when a common ancestor splits into two or more species

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4
Q

When was ‘Lucy’ alive?

A

3.2 million years ago

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5
Q

When was ‘Ardi’ alive?

A

4.4 million years ago

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6
Q

What is the genus and species of

‘Lucy’?

A

Australopithecus afarensis

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7
Q

What is the genus and species of

‘Ardi’?

A

Ardipithecus ramidus

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8
Q

What can fossil skulls tell us about a species?

A
  • diet
  • age
  • brainsize
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9
Q

What are the six categories of fossil types?

A
  • trace
  • mould and cast
  • replacement
  • petrified or permineralized
  • amber
  • original material
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10
Q

What is a

trace fossil?

and what are some examples?

A

any indirect evidence left by an organism

some examples are footprints, burrow and fossilized feces

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11
Q

What are

mould and cast fossils?

A

a mould is an impression of an organism
a cast is a mould filled with sediment

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12
Q

What are

replacement fossils?

A

fossils where the original material of an organism is replaced with mineral crystals that can leave detailed replicas of hard or soft parts

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13
Q

What are

petrified or permineralized fossils?

A

empty pore spaces that are filled in by minerals

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14
Q

What are

amber fossils?

A

Preserved tree sap that traps an entire organism. The sap hardens into amber and preserves the trapped organism.

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15
Q

What are

original material fossils?

A

original organisms that have been preserved by mummification or freezing

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16
Q

What are some of the problems that exist with using fossils solely as evidence for human evolution?

A
  • fossils are very rare
  • skeletons are often incomplete
  • the specimen might be an anomolous case
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17
Q

What are the 4 stages of classic fossilisation of a dinosaur?

A
  1. Dinosaur dies
  2. All soft tissues decay
  3. Earth is layered on top
  4. The bones become mineralised
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18
Q

Define

genetic variation.

A

Individuals in a population vary in their characteristics as a result of differences in their genes.

19
Q

Explain

Darwin’s theory of evolution.

A
  1. GENETIC VARIATION
    Individuals in a population vary in their characteristics as a result of differences in their genes.
  2. COMPETITION
    Individuals compete for resources. Some variations are better adapted to getting recources than others.
  3. NATURAL SELECTION
    Individuals with better-adapted variations are more likely to survive and reproduce.
  4. INHERITANCE
    The next generation will contain more individuals with the ‘better adapted variations’.
  5. EVOLUTION
    If the environment changes, natural selection will favour different variations. Over many generations, most of the individuals in the population will have the different ‘better adapted variations’. This may result in a new species.
20
Q

What are the 5 kingdoms in the

5 kingdom classification?

A
  • plants
  • animals
  • fungi
  • protists
  • monerans
21
Q

Why has genetic analysis shown that some relationships in the 5 kingdom system were incorrectly identified?

A

Because the characteristics were similar due to adaptation to the same environment rather than inheritance.

22
Q

Why is

genetic evidence better than evidence from observable characteristics for classification?

A

DNA isn’t changed by the environment.

23
Q

What are the three domains of the three domain system?

A
  • bacteria
  • archaea
  • eukaryota
24
Q

What is the kingdom in the bacteria domain?

A

enbacteria

25
Q

What is the kingdom in the archaea domain?

A

archaebacteria

26
Q

What are the kingdoms in the eukaryota domain?

A
  • protista
  • fungi
  • plants
  • animals
27
Q

Define

selective breeding.

A

A technique where humans control which organisms breed together to enhance their natural characteristics for human use.

28
Q

Define

genetic engineering.

A

A process which involves changing the DNA of one organism by inserting genes from another organism. This creates genetically modified organisms and is another way to introduce desirable characteristics to organisms.

29
Q

Define

aseptic technique.

A

the process of keeping things sterile

30
Q

What is

tissue culture?

A

The growing of cells or tissues in a liquid containing nutrients or on a solid medium (such as nutrient agar). The genetically identical cells form a clump called a callus. These cells may be treated to differentiate.

31
Q

Define

callus.

A

a clump of undifferentiated cells

32
Q

Define

differentiate.

A

become specialised

33
Q

Describe the stages of

micropropagation.

A
  1. A piece of plant is placed in bleach solution to sterilise it.
  2. A small piece of plant is cut off and placed on sterile nutrient medium to grow.
  3. The piece of plant is treated with hormones so that it grows roots and shoots.
  4. When the plants are large enough, they are planted into soil or compost.
34
Q

What are the positives of

micropropagation?

A
  • a large number of plants can be grown in a short period of time
  • healthy plants can be grown from diseased plants
  • plants without seeds can be multiplied
  • it is useful where sexual reproduction is not possible
35
Q

What are the negatives of

micropropagation?

A

there is no variation - a disease could wipe out the entire batch

36
Q

Why are bacteria very useful for genetic engineering?

A
  • they have plasmids
  • they reproduce asexually
37
Q

Define

vector.

A

A vehicle for carrying foreign DNA into a cell. It is used to transfer donor genes into recipient cells.

38
Q

What is the most commonly used vector in genetic engineering?

A

a plasmid

and additional genes are added to it

39
Q

What is

recombinant DNA?

A

a plasmid which has had genes from another organism inserted into it

40
Q

What are the different steps of

humans insulin production?

A
  1. There is a human pancreas cell containing DNA and a bacterium containing bacterial DNA and plasmid DNA.
  2. The human insulin producing gene is cut out of the human pancreas cell using restriction enzymes to create sticky ends.
  3. The plasmid DNA is cut out by the same technique to create complementary sticky ends.
  4. The two types of DNAs are combined to form recombinant DNA. Ligase enzyme is used to seal the ends.
  5. This recombinant DNA is introduced into a bacterial cell.
  6. These bacterial cells are put into a fermentation tank so that they can multiply rapidly.
  7. These recombinant bacteria produce human insulin.
  8. The insulin is extracted and purified.
41
Q

What are the benefits of

genetic engineering in crops?

A
  • the nutritional value of foods could be improved
  • crops can be produced that lack known allergens
  • crops can grow in arid conditions for better yield
  • genetically modified crops can produce herbicides to kill pests
  • food supply/agriculture can be improved in poor countries
  • genetically modified crops may have longer shelf lives
  • gowing insect resistant genetically modified crops reduces the amount of chemical used on crops to kill insects
  • growing herbicide resistant genetically modified crops makes it easier to kill weed but not crops
  • there is no evidence of harm to health from genetically modified crops so far
  • genes and proteins are broken down in the digestive system regardless of whether the food is genetically modified or not
  • less spraying is needed for genetically modified crops than for non-genetically modified varieties
  • economic costs and carbon footprint can be reduced because there is less need for land clearing and pesticide usage
42
Q

What are the risks of

genetic engineering in crops?

A
  • new traits could cause adverse health reactions
  • removals of traits coud have unkown effects
  • crops may limit biodiversity of local environment
  • cross pollination could lead to ‘super weeds’
  • foods with genetically modified components may not be labeled
  • different governments may have conflicting regulatory standards concerning safe usage
  • growing herbicide resistant genetically modified crops means that farmers can only use the herbicide that the crop is resistant to
  • if the insect resistance gene was transferred to weed plants, insects would be killed eating wild plants as well as crops
  • insects could evolve to stop being affected by a particular herbicide
  • genetically modified seed is usually more expensive than non-genetically modified seed
  • new genetically modified seed must be bought each year
43
Q

What is

Bt Maize?

A

A genetically modified Maize crop that has a bacterial gene known as Bt (derived from the soild bacterium Bacillus thuringiensis) inserted into its genome. This gene produces a protein that is toxic to insect pests.

44
Q

Define

yield.

A

the amount of food we get from a crop

Biology (4 decks)

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