Biology- Variation and selection

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  • Created by: Kitsune
  • Created on: 05-03-17 03:11
What is variation?
The difference between individuals of the same species
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What two types of variation are there?
Continuous and discontinuous
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Describe continuous variation
Characteristic has a range, quantitive, is affected by genes and environment
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Give examples of continuous variation
Height, body mass
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Describe discontinuous variation
You either have it or not, cannot be a measured, result of genes only
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Give examples of discontinuous variation
blood group, gender
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Give examples of both continuous and discontinuous variation.
Hair and eye color
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What 3 things can cause mutation?
Uneven distribution of chromosomes during division, damage to DNA, mistake in copying DNA
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What is gene mutation?
A change in the base sequence of DNA
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What are the symptoms of sickle cell anaemia?
Weakness, poor blood circulation, aching joints
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What gene is mutated in sickle cell anaemia?
Haemoglobin
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How is faulty hemoglobin made?
Faulty mRNA is made because the hemoglobin gene is mutated
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Mutation is the way in which new....
alleles are formed
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What are factors of mutation called?
mutagens
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What increases the rate of mutation?
Ionising radiation and some chemicals
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What is cancer?
Uncontrollable cell division
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What are the mutagens that cause cancer called?
Carcinogens
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What are adaptive features?
Inherited functional features of an organism that increase its fitness
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What is fitness?
Probability that an organism will survive and reproduce in its environment
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What is the result of more successful individuals breeding?
Their alleles will be passed in to successive generations
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What is evolution?
A change in adaptive features of a population over time as a result of natural selection
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What is selection pressure?
When food resources become available only to some so only those with adaptation features survive
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What is the process of adaptation?
Process, resulting from natural selection, by which populations become more suited to their environment over many years
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What is artificial selection?
Selecting those individuals that have the most useful characteristics and allowing only these individuals to breed
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What is another name for artificial selection?
Selective breeding
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Describe artificial insemination.
Desired males are stimulated to ejaculate. Their sperm is collect and frozen. It is taken to many farms to inseminate females
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Describe plant breeding.
Pollen is transferred form stamen of one flower to the stigma of another and after a plant with desirable characteristics is obtained it is multiplied by asexual reproduction.
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Who are the agents of selection in artificial selection? Natural selection?
Humans. Environment
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Is artificial selection after than natural?
Yes
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Artificial selection ........ to an organism in its natural environment
offers no advantage
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By what process are strains of antibiotic resistant bacteria formed?
Artificial selection
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Describe how a whole population of bacteria can become resistant
Mutation results in one resistant cell in the population. This cell survives and reproduces, giving rise to a resistant population.
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How can development of resistant bacteria be minimized?
By using antibiotics only when essential and ensuring complete treatment
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Other cards in this set

Card 2

Front

What two types of variation are there?

Back

Continuous and discontinuous

Card 3

Front

Describe continuous variation

Back

Preview of the front of card 3

Card 4

Front

Give examples of continuous variation

Back

Preview of the front of card 4

Card 5

Front

Describe discontinuous variation

Back

Preview of the front of card 5
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