Question 1
Selection pressure can affect homozygous individuals. The effect can be investigated using a model gene pool.
Why is a large gene pool necessary?
to ensure that genetic drift can occur if frequency is higher
to ensure that homozygous individuals are present in high frequency
to ensure that the effect of chance variations in gene frequencies are minimised
to ensure that Hardy–Weinberg equilibrium is achieved
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Question 2
A number of events occur for a new species to emerge in a population.
Which statement(s) correspond(s) to events that are involved in the formation of a new species?
1 - gene mutation
2 - selection pressure
3 - a change in the environment
1, 2, and 3
only 1 and 2
only 2 and 3
only 1
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Question 3
The adult wandering albatross, Diomedea exulans, has wingspans that range from 2.5 m to 3.5 m.
What describes the variation in wingspan of the wandering albatross?
intraspecific and controlled only by genetic factors
interspecific and controlled only by environmental factors
intraspecific and controlled by both genetic and environmental factors
interspecific and polygenic
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Question 4
The ability to roll one’s tongue is under the control of a single gene. The gene has two alleles R and r.
People who can roll their tongues can have the genotypes RR or Rr. People who cannot roll their tongues have the genotype rr.
A survey by a student showed that 12% of the population in a single school cannot roll their tongues.
The student then used the Hardy-Weinberg principle to calculate the number of heterozygous individuals in the school.
What is the percentage of heterozygous individuals at the student’s school?
Use the equations: p + q = 1 and p2 +2pq + q2 = 1
21.1%
22.7%
42.8%
45.3%
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Question 5
The two histograms represent the frequency distribution for the two different types of variation.
Which statement about characteristic Q is correct?
controlled by many genes and unaffected by the environment
controlled by one or two genes and unaffected by the environment
controlled by many genes and influenced by the environment
controlled by one or two genes and influenced by the environment
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Question 6
There are four different human blood groups: A, B, AB, and O.
This is because there are three different alleles coding for different proteins in red blood cells.
What describes this form of variation?
continuous and intraspecific
continuous and interspecific
discontinuous and intraspecific
discontinuous and interspecific
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Question 7
Which process directly results in sympatric speciation?
reproductive separation within the same environment
individuals moving to a new geographic area
a decrease in gene flow between populations
a sudden change in climate affecting a whole population
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Question 8
Which process results in allopatric speciation?
genetic mutations within a shared environment
phenotypic variations within a single population
direct competition within a population
geographic separation
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Question 9
What describes the situation when two distinct forms of a species survive and reproduce more successfully than intermediates?
sexual selection
directional selection
stabilising selection
disruptive selection
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Question 10
What does disruptive selection typically result in?
elimination of extreme phenotypes
an increase in phenotypic variation within the population
no change in the phenotype frequencies
a consistent phenotype that does not change over time
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Question 11
What type of selection favours phenotypes that vary in one direction from the mean of the population?
stabilising selection
directional selection
disruptive selection
artificial selection
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Question 12
What is/are the primary source(s) of genetic variation in sexually reproducing organisms?
mutation only
meiosis only
environmental factors only
mutation, meiosis, and random fertilisation
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