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Biology > Topic 4 - Natural Selection and GM > Flashcards

Topic 4 - Natural Selection and GM Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

theory of evolution

A
  • all species of living things today descended from the first simple life forms
  • new species arose from existing ones whilst others became extinct
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2
Q

what is evolution?

A

the slow and continuous change of organisms’ inherited characteristics from one generation to next

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3
Q

natural selection ( part 1 )

A
  • individuals in same species population show genetic variation
  • due to random mutation in DNA producing different alleles
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4
Q

natural selection ( part 2 )

A
  • selection pressures ( such as predation , disease ) affects an organism’s chance of surviving
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5
Q

natural selection ( part 3 )

A
  • those better adapted to the s.p have a better chance of survival and more likely to reproduce
  • alleles responsible for useful characteristic more likely to be passed down to next gen
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6
Q

natural selection ( part 4 )

A
  • less well adapted individuals less able to compete and therefore less likely to reproduce and survive
  • over time, they will decrease in number and eventually become extinct
  • beneficial characteristics become more common in the population over time
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7
Q

what is a fossil?

A

a trace of an animal or plant that lived millions of years ago and found in rocks

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8
Q

how can fossils be dated?

A
  • statigraphy : oldest fossils found in lower rock layers
  • radiometric dating
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9
Q

how do fossils prove evolution?

A
  • by arranging fossils in chronological order
  • gradual changes can be observed, showing development
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10
Q

who were the two scientists that were involved in theory of evolution?

A
  • charles darwin
  • alfred russel wallace
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11
Q

who did humans evolve from?

A

humans and chimpanzees evolved from a common ancestor - a species of ape

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12
Q

Ardi

A
  • fossil from 4.4 mill years ago
  • opposable big toe to grasp branches - suggests she climbed trees
  • long arms and short legs
  • brain size same as chimp
  • structure of legs suggests she walked upright
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13
Q

Lucy

A
  • fossil from 3.2 mill years ago
  • arched feet more adapted to walking, no opposable big toe
  • size of arms and legs in between chimp and human
  • brain were slightly larger than Ardi
  • structure of Lucy’s leg bone suggest she walked upright more efficiently
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14
Q

Leakey’s fossil : Turkana Boy

A
  • fossil from 1.6 mill years ago
  • short arms and long legs are much more like a human
  • brain size similar to human
  • structure of legs suggests he was even better adapted to walking upright
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15
Q

how do these fossils prove evolution

A
  • the more recent fossils are more similar to humans
  • longer legs, shorter arms
  • larger brain size
  • better adapted to walking
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16
Q

how are stone tools evidence for human evolution

A
  • the more recent tools are more complex
  • shows the human brain was getting larger, showing evolution
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17
Q

how does pentadactyl limb prove evolution?

A

they are limbs with five digits
you see it in all organisms with 4 limbs
- in diff groups of animals, they have similiar bone structure but diff function
- similar bone structure provides evidence of common ancestor

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18
Q

what are the five kingdoms

A
  • animals
  • plants
  • fungi
  • protists
  • prokaryotes
19
Q

classification method divisions
( Kids Prefer Cake Over Free Green Salads )

A
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
20
Q

how has our understanding of biochemical processes and genetics increased?

A
  • scientists able to determine sequence of DNA bases in diff organisms’ genes
  • compare them. more similar : closely related
21
Q

how did genetic analysis led to the suggestion of 3 domain classification

A
  • using RNA sequencing
  • Woese found out that some members of prokaryote kingdom weren’t as closely related as thought
  • archaea domain are quite different to bacteria domain as their DNA & RNA sequencing shows
22
Q

what is selective breeding?

A

it is when humans artificially select the plants and animals to breed so the genes for particular characteristics remain in population

23
Q

difference between selective breeding and natural selection

A
  • selection pressure causes better adapted species to reproduce in natural selection
  • humans choose which animals to reproduce in selective breeding
24
Q

how does selective breeding work?

A
  • from existing stock, humans select which have desired characteristics
  • breed them with each other
  • select best of offspring and breed them together, continue process over next several generations
25
Q

uses of selective breeding

A
  • improve crop yields
  • more meat from cows and pigs
  • more milk from cows
26
Q

problem with selective breeding

A

reduces the gene pool

27
Q

why is reducing gene pool harmful?

A
  • more chance of inheriting harmful genetic defects
  • if a new disease appears, there is not much variation so it if it kills one, others are likely to succumb
28
Q

what is tissue culture

A

when cells are grown in an artificial growth medium

29
Q

plant tissue culture use

A
  • grow plants from the cells of a single individual
  • plants produced are clones and are genetically identicaql
30
Q

process of plant tissue culture ( p1)

A
  • choose the plant to clone, with beneficial characteristics
  • remove small pieces of tissue from plant stems, called explants
    -placed in artificial growth medium ( agar jelly ) that contains growth medium and nutrients to help tissue grow into plants
31
Q

process of plant tissue culture ( p2 )

A
  • done under aseptic conditions to prevent growth of microbes that could harm plants
  • when the plants have grown roots they are moved to glasshouse and placed in pot containing compost
  • light intensity, temp controlled
32
Q

advantages of plant tissue culture

A
  • plants can be grown quickly
  • all year round
  • in very little space
  • all plants will have desired characteristic
33
Q

what is genetic engineering?

A
  • a gene is transferred from one organism’s genome to another organism’s genome
  • in order to introduce desirable trait
34
Q

uses of genetic engineering

A
  • improve size and quality of fruit
  • cows produce useful human proteins in milk
  • bacteria producing human insulin
35
Q

process of genetic engineering (p1)

A
  • plasmid vector physically removed from bacterium
  • restriction enzyme used to cut open plasmid DNA to produce uneven sticky ends
  • same restriction enzyme used to cut out desired gene
  • vector DNA and gene with complimentary sticky ends
36
Q

process of genetic engineering (p2)

A
  • dna ligase enzyme joins complimentary sticky ends together
  • makes recombinant dna
  • recombinant dna is inserted into bacteria which is now a gmo
  • can divide millions of times and all produce protein we want
37
Q

benefits of genetic engineering

A
  • has a more immediate effect than selective breeding
  • as DNA carries a universal code, genes can be transferred from ANY species
38
Q

concerns about genetic engineering

A
  • hard to predict what effect changing the genome will have on organism
  • transplanted genes may get out into environment
  • herbicide resistant gene can be picked up by weeds - superweed
39
Q

benefits of GM crops

A
  • increase the amount of food a crop provides : its yield
  • Gm crops can be engineered to contain additional nutrients
40
Q

concerns about gm crops

A
  • concerns about long term effects of gm crops on human health
  • countries may be too dependent on gm seeds
41
Q

benefits of bt crops

A
  • improves crop yields as insects are killed off
  • reduces need for chemical pesticides
42
Q

risks of bt crops

A
  • insects constantly exposed to toxin so could develop resistance
43
Q

other methods of increasing food production

A
  • fertilisers
  • biological control
44
Q
A

Biology (9 decks)

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