Variation,Natural Selection and Selective Breeding Flashcards Preview

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Flashcards in Variation,Natural Selection and Selective Breeding Deck (14)
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1
Q

What is variation ?

A

It is the differences between individuals

2
Q

What are the two main types of variation ?

A
  • Continuous - e.g. Height, where there is a smooth range of measurements
  • Discontinuous - e.g. Blood group, where there are distinct categories with no values in between
3
Q

Why are there differences between individuals ?

A
  • differences in genes they inherit

* and the conditions in which they develop ( environmental causes )

4
Q

What happens when a mutation occurs in a body cell ?

A

It will affect only those cells produced by mitosis from the affected cell. This type of mutation is not inherited. Mutations in body cells can give rise to cancer of the cells that are affected.

5
Q

What happens when a mutation occurs during meiosis in a gamete ?

A

It will affect all the cells in the individual which develops from the gamete. This means that the mutation is inherited.

6
Q

What was Darwin’s theory based on ?

A
  • all living things show variation

* all living things tend to over reproduce

7
Q

What was Darwin’s theory ?

A
  • there will be a struggle for existence because organisms over reproduce, resources will be limited
  • Some will be better adapted to their environment than others because they vary
  • those who are best adapted to survive reproduce in great numbers, the less well adapted do not reproduce as much
8
Q

What is the anagram to help remember natural selection ?

A

M - MUTATION in individual
V - result in natural VARIATION
A - individual has an ADVANTAGE over others, extinction of species unable to compete
R - surviving individuals REPRODUCE
P - advantage alleles for mutation are PASSED on
S - repeated over SEVERAL generations

9
Q

What are Antibiotics?

A

There are chemicals that kill bacteria and do not harm animal cells

10
Q

How do you antibiotics not harm animal cells while killing bacteria ?

A

They target cell structures such as cell walls, which animal cells do not have

11
Q

How have antibiotics stoped working overtime ?

A
  • originally, none of the bacteria was resistant to the antibiotic
  • doctors began to use the Antibiotic, which kills the bacteria
  • A chance mutation gave some bacteria resistance to the antibiotic
  • these bacteria are better adapted to an environment in which the antibiotic was used
  • they survive in greater numbers to reproduce and pass on the resistance allele
  • this was repeated with each generation of bacteria
  • The proportion of bacteria with resistant allele increased until most had the allele
12
Q

What does selective breeding mean ?

A

A means of producing animals and plants with desirable characteristics by choosing individuals to breed from and by repeating the process for many generations

13
Q

How is selective breeding performed ?

A
  • selecting the desired organisms from the population and breeding them together
  • look at the offspring for those with the best combination of desired features
  • use only these individuals for breeding the next generation
  • repeat the selection generation after generation
14
Q

Techniques for selective breeding

A
  • traditional selective breeding
  • artificial insemination
  • embryo transplantation
  • cloning
  • genetic engineering