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Biology > B14-Variation and evolution > Flashcards

B14-Variation and evolution Flashcards

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1
Q

What is Variation ?

A

All the differences in the characteristics of individuals in a population .

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2
Q

Waht is the first cause of variation ?

A

-The alleles (characteristics) that individuals have inherited - geentic causes .
Example of genetic causes is eye and hair colour .

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3
Q

What is the second cause of variation ?

A

Environment , eg-language .

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4
Q

What is the third cause of Varition ?

A

-A combination of genes and the environment .
Example - height , some alelels which make you grow taller , BUT ALSO CAN BE AFFECTED by diet , calcium for bones to fully devlop .

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5
Q

In any population of a species there is a amssive amount of egentic variation .

A

.

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6
Q

What causes genetic variation

A

Mutations

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7
Q

What are mutations

A

Random changes to DNA .

-Take place all the time and mosr have no effect at all on the phenotype .

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8
Q

What can some mutations do ?

A

-Some mutations may influence the phenotypes - alelles for tallness MAY lead to tallness if diet is suitable .

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9
Q

What is another thing mutations can do ?

A

-A small number of mutation can actually determine the phenotype - eye colour .

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10
Q

What is another thing mutations can do (black moths and white moths )

A

-Very rarely , a mutation can lead to a new phenotype .

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11
Q

-What can a new phenotype be beneficial for , what can it lead to ?

A

-A new phenotype can be beneficial if environment changes leading to rapid change in a species .

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12
Q

What is natural selection ?

A

-Organisms that can gain an advantage and therefore are more liekly to survive and breed .

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13
Q

What is the first stage of the survival of the fittest process ?

A

-Individual organsisms within a particular species may show a wide range of phenotype and genetic variation .

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14
Q

What is the second stage of the survival of the fittest process ?

A

-Individuals with characteristics msot suited to the environment are most likely to survive and breed sucessfully .

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15
Q

What is the third stage of the survial of the fittest process ?

A

-The alelles (variants) that have enabled these individuals to survive are then passed onto the next generation .

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16
Q

What happpens when two populations of one species become too different in phenotypes ?

A
  • They can no longer interbreed to produce fertile offspring .
  • these two populaitons have now become two separate species .
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17
Q

Humans realised wolves were useful how ?

A
  • Wolves can protect you by alerting you

- Wolves can keep you warm and company .

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18
Q

Why have domestic dogs been selectievly bred ?

A

-They have been selectively bred to have a gentle nature .

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19
Q

Why have food crop have been selectively bred ?

A

-They have been selectiely bred to be resistant to disease .

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20
Q

Why have animals been selectively bred ?

A

-They have been selectively bred to produce more meat or milk .

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21
Q

Why have certain plants been selectively bred ?

A

-They have been slectively bred to produce large or unusal flowers .

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22
Q

What is the first stage of selective breeding ?

A
  1. Selec two individuals (male and femlae if animlas) from a mixed population who have best of that characteristcis .
    - Breed parents together .
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23
Q

What is the second stage of selective breeding ?

A

-Reproduction produces variaition in offspring so some offspring will have the desired chat=racteristic but others won’t .

24
Q

What is the third stage of selective breeding ?

A
  • Select offspring with the ‘best’ characteristic and breed together .
  • Continue doing this over many generations until all offspring have that characterstic .
25
Q

What is the risk of selective breeding .

A

-If we breed otgetehr closely related animals and plants , we can get inbreeding .
-Inbreeding can cuase some breeds to be prone to disease or inherited diseases .
(dogs epilepsy )

26
Q

What are clones ?

A

-Clones are genetically identical organisms through asexual reproduction .

27
Q

Advantage of cloning plants

A

-As the clone is genetically identical to the original plant , we know exactly what the clones characteristics will be (colour of the flowers ).

28
Q

What will the offspring be like if we use seeds ?

A

-As seeds re produced by sexual reporudction , all the offspring would be different .

29
Q

What is a simple wy to clone a plant

A

-to take cuttings - gardeners have used this method for a long time .

30
Q

How do you take cuttings ?

A
  • A small piece of the plant is removed and the end is dipped in rooting powder .
31
Q

How do you take cuttings (2) ?

A
  • Rooting powder contains plant hormones and htis encourgaes plants to develop roots .
  • By taking cuttings , we produce a genetically identitcal clone as a starter plant .
32
Q

Disadvantage of taking cuttings ?

A

-Good for small amount of clones but cannot bedone for large amount ?

33
Q

What do we do to clone large amounts of plants ?

A

-Tissue Culture

34
Q

What is the first stage of tissue culture ?

A

-We take a palnt that we want to clone and we divide the plant into hundreds of tiny pieces .

35
Q

What is the second stage of tissue culture ?

A
  • Each of these pieces ocntains a small number of cells .

- These small groups of cells are then incubated with plant hormones .

36
Q

What do plant hormones do ?

A

Plant hormones stimulate plant to grow and develop into fully-gorwn clones .

37
Q

Why do conditons for tissue culture must be sterile ?

A

-As we don’t want to intorudce any microrganisms liek bacteria and fungi .

38
Q

What is one reason why tissue culture is useful in commercial plant nuseries ?

A

-It allows growers to produce genetically identical plants , quickly and cheaply and as all the plnts are clones , gardeners can be certain what characteristics they want .

39
Q

What is another reason why tissue culture is useful in commercial plant nurseries ?

A

It is also useful to preserve rare species .

40
Q

What are the two ways to clone animals

A
  • Embryo Transplants

- Animal Cell Cloning

41
Q

What is the first stage of embryo transplants ?

A

-Giver fertility hormones to the female .
extract sperm and an egg cell from the naimals with the
characteristics we want .

42
Q

What is the second stage of embryo transplants ?

A

Fertilisation produces a fertilised egg .

43
Q

What is the third stage of embryo transplants ?

A

Allow the fertilised egg to develop into an early stage embryo .
-It is very important that the cells in thembryo must not have started to specialise .

44
Q

What is the fourth stage of embryo transplants?

A

We now use a glass rod to split the embryo into two .

45
Q

What is the fifth stage of embryo transplants

A

Finally we transplant the two mebryos into hsos t mothers womb .
-The embryos will then grow and develop . When these aniamals are born , you get two identical offsprings (clones)

46
Q

What is the benefit of adult cell cloning rather than embryo transplants ?

A

When cloning from an adult , we know the characteristics the clone we wil have unlike embryo transplants .

47
Q

What is the first stage of Adult Cell Cloning

A

.Start by removing a cell from the animal we want to clone .

48
Q

What is the second stage of Adult Cell Cloning

A

We then remove the nucleus from this cell .

-This nucleues cotains the genetic information from the animal that we are cloning .

49
Q

What is the third stage of Adult Cell Cloning

A

Take an unfertilised egg cell from the same species.

50
Q

What is the foruth stage of Adult Cell Cloning

A

Then remove the nuecleus from the unefertilised egg and throw it away so it has no egentic material at all .

51
Q

What is the fifth stage of Adult Cell Cloning

A

Insert the nucleus from the original audlt body cell into the epty egg cell .
-Now the egg cell only containts genetic information from the animal we are cloning .

52
Q

What is the sixth stage of Adult Cell Cloning

A

Then give the egg cell an electric shock ,causing the egg cell to divide and form an embryo .

53
Q

What is the seventh stage of Adult Cell Cloning

A

These embryo cells conntan the same genetic information as the adult skin cell we started with .

54
Q

What is the eight stage of Adult Cell Cloning

A

When the embryo has developed into a ball of cells , it is then inserted into the wom of an adult female ,t o continue is development .
Host mother then gives brith to clone .

55
Q

Why does the clone look nothing like the mother in Adult Cell Cloning ?

A

As the clone contains none of her genetic material .

Biology (25 decks)

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