B14.1 - 14.7 - Variation And Evolution✔️ Flashcards

1
Q

Define variation?

A

Is the difference in the characteristics of individuals in a population

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2
Q

Define natural selection?

A

Natural selection is a process where organisms that are better adapted to an environment will survive and reproduce

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3
Q

How do mutations impact organisms?

A

Mutations can take place when a cell divides and is a result of a change in the DNA code - some mutation are harmful and can result in the organisms death very rarely a mutation produces an adaption that makes the organism better suited to its enviorment

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4
Q

State the theory of evolution by natural selection ….?

A

All species of living things have evolved from simple life forms that first developed more than 3 billion years ago - evolution through natural selection produces changes in the inherited charcteristics of a population over time

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5
Q

Summarise evolution?

A

-individual organisms within a particular species may show a wide range of phenotype and genetic variation

-individuals with characteristics most suited to the enviorment are most likley to survive

-the alleles that have enabled these individuals to survive are then passed on to the next generation

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6
Q

How can a mutation lead to a change in species?

A

Rarely a mutation leads to a new phentotypes - If the new phenotype is suited to an enviormental change it can lead to a relatively rapid change in the species

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7
Q

4 Uses of selective breeding?

A

-disease resistance in food crops
-animials that produce more milk or meat
-domestic sogs and farm animials with a gentle nature
-large,unsual,bright,heavlt scented flowers

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8
Q

How does selective breeding work?

A

Farmers select animials from a mixed population that have useful or desirable characteristics they breed these animials together and select the offspring that best show these characteristics this continues over many generations

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9
Q

3 factors that may result in variation?

A
  • genes that they have inherited
  • conditions in which they have developed
  • combination of genes and the enviorment
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10
Q

What can cause a rapid change in species?

A

Very rarely mutations will lead to a new phenotype - if a new phenotype is suited to an enviormental change it can lead to a relativley rapid change in the species

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11
Q

How can new species be formed?

A

If two populations of one species become so different in phenotype (observable characteristics) that they can no longer intebreed to produce fertile offspring they have formed two new species

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12
Q

Define evolution?

A

Change in the inherited characteristics of a population over time through a process of natural selection which may result in the formation of a new species

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13
Q

Define selective breeding?

A

Process where humans artificially select the plants or animials to breed for desired genetic characeteristics eg crops that are disease resistant

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14
Q

What does selective breeding involve - explain the process?

A

Involves choosing parents with the deired characteristics from a mixed population - they are bred together - offspring that best show the desired characteristics are bred together this repeats over many generations - until all offspring show the desired characetristics

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15
Q

Explain in 4 steps the process of selective breeding?

A

1)from existing stock, select the ones which best display desired characetristics

2)breed them together

3)select the best of the offspring and breed them together

4)continue process over many generations - until the desired trait gets stronger

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16
Q

Give 4 desireable characteristics which can be obtained through selective breeding?

A
  • disease resistance crops
  • animials which produce more meat or milk
  • domestic dogs with gentle nature
  • large or unusual flowers
17
Q

What is an issue with selective breeding?

A

Can lead to “inbreeding” where some breeds are particularly prone to disease or inherited defects - this is a result of a limited gene pool

18
Q

Why can the arise of a new disease be dangerous to a poputaion produced through selective breeding?

A

Lack of gene pool and decreased variation will mean if one of them are killed by a new disease most of them are going to be killed aswell

19
Q

Define genetic engineering?

A

A process which involves modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic

20
Q

Describe the process of genetic engineering?

A

1) useful gene is isolated from another organism’s genome using enzymes and is inserted into a vector

2) vector is usually a virus or a piece of circular DNA found in bacterial

3) vector is used to insert the gene to the target organisms cells - so they develop with desired characteristics

21
Q

2 examples where genetic engineering has been used?

A
  • plant crops engineered to be resistant to disease or produce bigger better fruits
  • bacterial cells engineered to produce substances like human insulin
22
Q

Issues with GM (genetically modified) crops?

A
  • will affect the number of wild flowers which will reduce population of insects
  • may be issues on human health through eating them
  • transplanted genes may get into natural enviorment - herbecide resistance genes could be picked up by weeds creating ‘superweeds’
23
Q

How can GM crops be used to help poorer people?

A

GM crops could be engineered to contain the nutrients missing for example golden rice is a GM crop that can help reduce blindness by providing needed vitamins

24
Q

What is tissue culture?

A

Mordern way of cloning plants - by using small groups of cells from part of a plant to grow identical new plants - important for preserving rare plant species

25
Q

What is cuttings technique used for?

A

Older and simpler method of producing many identical new plants from a parent - used by gardeners

26
Q

What is embryo transplant?

A

Process of splitting apart cells from a devloping animial embryo before they become specialised , then transplanting the identical embryos into host mothers

27
Q

Explain process of making cow clones through embryo transplants?

A
  • sperm cells taken from best male cow and the eggs are taken from best female cow
  • sperm is used to artificially fertelise an egg cell and the embryo that develops is then split many times to form clones

-cloned embryos can be implanted into lots of other female cows where they grow into baby calves

  • hundreds of ideal offspring can be produced every year
28
Q

Explain the process of adult cell cloning?

A

nucleus is removed from an unfertilised egg cell - nucleus from an adult body cell, such as skin cell is inserted into egg cell - an electric shock stimulates egg cell to divide to form an embryo - these embryo cells contain same genetic information as the adult skin cell - when embryo has developed into ball of cells it is inserted into womb of adult female to continue development

29
Q

What are some issues with cloning?

A
  • reduced gene pool, increases chance of a population all getting wiped out from a disease
  • cloned animials might not be as healthy as normal ones
  • could lead to human cloning in the future