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GCSE AQA Biology Flashcards > B14 Variation and Evolution > Flashcards

B14 Variation and Evolution Flashcards

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1
Q

What are inter-specific variation?

A

Variation between different species

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2
Q

What is intra-specfic variation?

A

Variation between organisms of the same species.

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3
Q

What is an example of inter-specific variations?

A

Humans and monkeys

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4
Q

What is an example of intraspecifc variations?

A

Skin colour

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5
Q

What factors can cause variations?

A
  • genetic factors only
  • enviromental factors only
  • genetic and enviromental factors both
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6
Q

Examples of genetics only variations?

A
  • Blood type
  • Skin colour
  • Hair colour
  • Attached earlobe
  • Ability to roll tounge
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7
Q

Examples of enviroment only variations?

A
  • Accent
  • Languages
  • Music
  • Scarring
  • Sports
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8
Q

Examples of genetic and enviromental variations?

A
  • weight
  • height
  • skin tan colour
  • intelligance
  • life expectancy
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9
Q

What is variation?

A

Variation is the differences between individuals of a population

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10
Q

What does a mutation do?

A

Causes change to the protien that is expressed

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11
Q

What is natural selection?

A

A process where organisms that are better adapted to an environment will survive and have more offspring. This means their genes are passed on to the future generations.

  • This process is fundamental to the process of evolution
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12
Q

What term did Charles Darwin give to explain natural selection and his theory of evolution?

A

Survival of the Fittest

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13
Q

What is selective breeding?

A

An artificial process in which humans breed plants and animals for particular genetic characteristics.

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14
Q

What are the steps for selective breeding?

A

1) Select parents with desired characteristics
2) Breed the parents (control pollination in plants)
3) Choose the best offsprings with desired characteristics to breed for the next generation
4) Repeat this process over many generations until all offsprings have desired characteristics

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15
Q

Give examples of selective breeding being used in animals?

A
  • Highland cows and Arberdeen Angus cows have been bred for their meat
  • Friesian cows have been bred to produce large volumes of milk
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16
Q

What are examples of desired characteristics in plants?

A
  • disease resistance in food crops
  • wheat plants that produce lots of grain
  • large or unusual flowers
17
Q

What are examples of desired characteristics in animals?

A
  • animals that produce lots of milk or meat
  • chickens that lay large eggs
  • domestic dogs that have a gentle nature
18
Q

How can we determine that two populations of a species has become to different species?

A

If the two species have become so different that they can’t interbreed to produce fertile offspring, then two new species has formed

19
Q

What are the risks of selective breeding?

A
  • Reduced genetic variation can lead to attack by specific insects or disease, which could be extremely destructive
  • Rare disease genes can be unknowingly selected as part of a positive trait, leading to problems with specific organisms, eg a high percentage of Dalmatian dogs are deaf
  • Can create physical problems in specific organisms, eg large dogs can have faulty hips due to not being formed correctly
20
Q

What is genetic engineering?

A

The modification of the genome of an organism by introducing a gene from another organism to result in a desired characteristcs

21
Q

What are the steps of genetic engineering?

A

1) Enzymes are used to isolate the required gene, this gene is inserted into a vector, which is usually a bacterial plasmid or a virus.

2) The vector inserts the gene into required cells.

3) The genes are transferred to animal, plant or microorganism cells, during early development. This allows them to develop with the desired characteristics.

22
Q

Give an example of genetic engineering.

A

Insulin producing bacteria
Golden rice
Disease resistant crops

23
Q

What is an advantage of golden rice?

A

Populations where vitamin A deficiency is common can grow it to prevent blindness.

24
Q

What are the ethical issues concerned with genetic modifaction/engineeing?

A
  • It may contain possible health risks, release of toxins or allergic reactions
  • Others think it’s ethically wrong to create new life forms or to move genes between organisms
25
Q

Give a future use of genetic engineering?

A

In the future researchers are hoping to use genetic engineering to be able to overcome some inherited disorders, such as cystic fibrosis and Huntington’s disease amongst others.

26
Q

What are the benefits of genetic engineering?

A
  • Genetic modification is a faster and more efficient way of getting the same results as selective breeding.
  • Improve crop yields or crop quality, which may help reduce hunger around the world.
  • Introduce herbicide resistance, which results in less herbicides being used
  • Insect and pest resistance can be developed and inserted into the plants. The plant produces toxins, which would discourage insects from eating the crop.
  • Sterile insects could be created such as a mosquito. They would breed, which would lead to infertile offspring. This may help with spread of diseases, such as malaria ans dengue fever
27
Q

What are the risks of genetic engineering?

A
  • Transfer of the selected gene into other species. What benefits one plant may harm another.
  • Some people believe it is not ethical to interfere with nature in this way.
  • GM crop seeds are often more expensive and so people in developing countries cannot afford them.
  • GM crops could be harmful, for example toxins from the crops have been detected in some people’s blood.
  • GM crops could cause allergic reactions in people.
  • Pollen produced by the plants could be toxic and harm insects that transfer it between plants.
28
Q

What is a clone?

A

An organism that is genetically identical to another organism.

29
Q

What are the different methods of cloning in plants?

A
  • Cuttings
  • Tissue Culture
30
Q

How are cuttings used to clone plants?

A

1) A branch from the parent plant is cut off, its lower leaves are removed, and the stem is planted in damp compost.

2) Plant hormones are often used to encourage new roots to develop. The cutting is usually covered in a clear plastic bag to keep it moist and warm. After a few weeks, new roots develop and a new plant grows.

31
Q

What is another name for cloning in tissue culture?

A

micropropagation

32
Q

How can we use tissue culture in the cloning of plants?

A

1) Explants are placed in Agar growth medium containing nutrients and auxins

2) Samples develop into tiny plantlets

3) Plantlets planted into compost

33
Q

Why is cloning by tissue culture more expensive than cuttings?

A

They are growm in virto (in glassware) using sterile agar jelly that contain plant hormones and nutrients

34
Q

What are the different methods of cloning in animals?

A
  • Embyro transplants
  • Adult cell cloning
35
Q

How can embryo transplants be used in animal cloning?

A

1) Sperm is taken from bull and artificially inseminated into cow

2) Zygotes develop into embryos in cow and then removed from the uterus

3) Embryos are split into several smaller cells before they become specialised, each of which can grow into a new calf

4) Identical embryos are transplanted into host mothers

36
Q

How can adult cell cloning be used in animal cloning?

A

1) The nucleus is removed from an unfertilised egg cell.

2) The nucleus from an adult body cell, such as a skin cell, is inserted into the egg cell.

3) An electric shock stimulates the egg cell to divide to form an embryo.

4) These embryo cells contain the same genetic information as the adult skin cell.

5) When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development.

GCSE AQA Biology Flashcards (18 decks)

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