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GCSE AQA Biology > B14 - Variation > Flashcards

B14 - Variation Flashcards

1
Q

variation

A

differences in the characteristics of individuals in a population

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2
Q

variation due to

A

inherited
-environment
-or both

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3
Q

Natural selection

A

organisms are in competition with members of the same species
-ones that are at an advantage survive and breed

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4
Q

Variation within a species

A

genes are inherited

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5
Q

new variants

A

result of mutation
-Change in dna code

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6
Q

mutations when gametes are formed

A

affect phenotype
-new variants into genes

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7
Q

mutations rarely

A

produce an adaptation for the organism

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8
Q

theory of evolution by natural selection

A

all species have evolved from simple life forms
-produces a change in inherited characteristics
better adapted species

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9
Q

process of natural selection + evolution

A
  • genetic variation within species
  • better adapted individuals survive + breed
    -alleles that are well adapted are passed on
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10
Q

when do two population split and become their own species

A

when they can no longer interbreed to produce fertile offspring

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11
Q

rapid change in species due to

A

a new phenotype which is better suited to the environment

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12
Q

selective breeding

A

speeds up natural selection by selecting animals or plants for breeding that have a required characteristic

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13
Q

Farmers eg of selective breeding

A

-select ones with desirable characteristics
-forms a breeding stock

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14
Q

Desirabl characteristics eg

A

-disease resistant crops
-animals that produce more meat/milk
-gentle nature dogs
-heavily scented flower

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15
Q

con of selective breeding

A

strange combination of genes that wouldn’t have occured naturally
- reduced variation
-inbreeding

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16
Q

pro of selective breeding

A

useful organisms have been produced

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17
Q

inbreeding causes

A

pront to disease + inherited defects
-lack of variation

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18
Q

lack of variation means

A

-reduces number of alleles
-if conditions are unstable and changes
-won’t be able to cope with change
-death of species

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19
Q

geentic engineering

A

involves modifying genetic material of an organism

20
Q

process of genetic engineering

A

enzymes isolate + cut out required gene
-inserted into vector using more enzymes
-genes are transferred at an early stage
-organism grows to develop this characteristic

21
Q

vector used genetic engineering

A

usually bacterial plasmid / virus

22
Q

plants genetic engineering

A

desired genes inserted into meristemc ells
-used to produce identical clones

23
Q

GM bacteria/fungi

A

-cultred on a large scale
-make lots of protein (insulin)
-but there is a limit to hm protein is made

24
Q

GM crops

A

-increases yield + size + nutrition
-resistant to disease/ insect
- resistant to herbicide

25
Q

GM crops - resistant to insects

A

-make their own pesticide

26
Q

GM crops - resistant to herbicide

A
  • farmers can kill weed w/o damaging crops
27
Q

clone

A

individual produced asexually and genetically identical to parent

28
Q

tissue culture = cloning

A

-expensive
-allows many clones to be made from a small piece of tissue

29
Q

process of tissues culture

A

-mixture of hormones to group cells that are needed
-produces a callus
-using hormones/right conditions = stimulates growth of cells to be a new plant

30
Q

callus

A

big mass of identical plant cells

31
Q

Tissue culture pros

A

-high quality w desired qualities
-used commercially in plant nurseries
-preserves rare plant species

32
Q

taking cutting

A

-older + simpler
-produces identicalt o parent plant
-used by gardeners

33
Q

Cloning cattle embryos process

A

-fertility hormones to top quality cow to produce may eggs
-fertilise egg w sperm
-embryonic cells are split and transplanted into surrogate
-produces identical twins

34
Q

Cloning cattle embryos process - fertilisation

A

-inside a cow and embryos are washed out of uterus
-or eggs are collected and fertilised in a lab

35
Q

pros of Cloning cattle embryos process

A

-produces more calves
-produces GM embryos = useful
-carried to places in need (dry areas)

36
Q

cons of Cloning cattle embryos process

A

-expensive
-highly skilled work

37
Q

can mamals reproduce asexually

A

never

38
Q

adult cell cloning

A

-new whole animal is produced from the cell of another adult animal

39
Q

adult cell cloning proces

A
  • nucleus is removed from unfertilised egg
  • nucleus is removed from an adult body cell
  • nucleus is inserted into egg cell
    -electric shock = stimulates division to from embryonic cells
    -embryo is inserted into surrogate
40
Q

pros of adult cell cloning

A

-produce useful proteins in milk
-produces medically useful animals
-prevents extinction and brings back species
-clones pet = dna lives on but ethical concerns

41
Q

risks of adult cell cloning

A

-cloning human babies = ethical concerns
-reduces variation

42
Q

benefits of genetic tech

A
  • curing inherited disorders by replacing faulty genes
    -produce proteins for humans from GM organisms (insulin)
  • GM mice to mimic human disease = cure
43
Q

Pros of genetic tech in agriculture

A

-improved growth rates of plants
-increase food value + yield
-drought resistant
- herbicide resistant + makes own pesticides

44
Q

Concerns of genetic tech agriculture

A

-GM food can affect human diet
- GM organisms on nature
- fears human engineering (designer babies)

45
Q

Concerns of genetic tech agriculture - GM organisms on nature

A
  • they are infertile = farmers repurchase seeds
    -if infertile genes spread damage ecosystems

GCSE AQA Biology (45 decks)

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