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?

  A  

to ensure that genetic drift can occur if frequency is higher

  B  

to ensure that homozygous individuals are present in high frequency

  C  

to ensure that the effect of chance variations in gene frequencies are minimised

  D  

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

  A  

1, 2, and 3

  B  

only 1 and 2

  C  

only 2 and 3

  D  

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?

  A  

intraspecific and controlled only by genetic factors

  B  

interspecific and controlled only by environmental factors

  C  

intraspecific and controlled by both genetic and environmental factors

  D  

interspecific and polygenic

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Question 4

What is not associated with the use of artificial selection in farm animals?

  A  

health problems in more productive breeds

  B  

inbreeding

  C  

increased frequency of mutations

  D  

reduced gene pool

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Question 5

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

  A  

21.1%

  B  

22.7%

  C  

42.8%

  D  

45.3%

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Question 6

The two histograms represent the frequency distribution for the two different types of variation.

Which statement about characteristic Q is correct?

  A  

controlled by many genes and unaffected by the environment

  B  

controlled by one or two genes and unaffected by the environment

  C  

controlled by many genes and influenced by the environment


  D  

controlled by one or two genes and influenced by the environment


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Question 7

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?

  A  

continuous and intraspecific


  B  

continuous and interspecific


  C  

discontinuous and intraspecific

  D  

discontinuous and interspecific

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Question 8

What is the likely outcome when a mutation results in a trait that improves an organism's survival and reproduction?

  A  

the trait will disappear from the population

  B  

the frequency of the advantageous allele will increase

  C  

the population will become more susceptible to predators

  D  

the mutation will remain neutral with no effect on the population

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Question 9

What does stabilising selection typically do to a population's characteristics?

  A  

it favours phenotypic extremes

  B  

it increases genetic diversity

  C  

it leads to new species formation

  D  

it preserves the average traits

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Question 10

What are characteristics that are influenced by more than one gene are called?

  A  

mutations

  B  

polygenes

  C  

alleles

  D  

genotypes

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Question 11

Which type of selection favours individuals that vary in one direction from the mean of the characteristic?

  A  

directional selection

  B  

stabilising selection

  C  

disruptive selection

  D  

artificial selection

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Question 12

What type of selection could lead to antibiotic resistance in bacteria?

  A  

directional selection

  B  

stabilising selection

  C  

sexual selection

  D  

disruptive selection

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Question 13

What is an example of a characteristic that may be selected for by directional selection in a changing environment?

  A  

average height

  B  

intermediate skin pigmentation

  C  

symmetrical facial features

  D  

antibiotic resistance in bacteria

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Question 14

What change occurs in a population's normal distribution curve during directional selection?

  A  

it shifts in the direction of the advantageous trait

  B  

it becomes narrower with reduced variance

  C  

it remains the same, as only allele frequencies change

  D  

it splits into two distinct peaks indicating disruptive selection

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Question 15

What is/are the primary source(s) of genetic variation in sexually reproducing organisms?

  A  

mutation only

  B  

meiosis only

  C  

environmental factors only

  D  

mutation, meiosis, and random fertilisation

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Question 16

What type of selection favours phenotypes that vary in one direction from the mean of the population?

  A  

stabilising selection

  B  

directional selection

  C  

disruptive selection

  D  

artificial selection

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Question 17

What does disruptive selection typically result in?

  A  

elimination of extreme phenotypes

  B  

an increase in phenotypic variation within the population

  C  

no change in the phenotype frequencies

  D  

a consistent phenotype that does not change over time

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Question 18

What describes the situation when two distinct forms of a species survive and reproduce more successfully than intermediates?

  A  

sexual selection

  B  

directional selection

  C  

stabilising selection

  D  

disruptive selection

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Question 19

Which process results in allopatric speciation?

  A  

genetic mutations within a shared environment

  B  

phenotypic variations within a single population

  C  

direct competition within a population

  D  

geographic separation

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Question 20

Which process directly results in sympatric speciation?

  A  

reproductive separation within the same environment

  B  

individuals moving to a new geographic area

  C  

a decrease in gene flow between populations

  D  

a sudden change in climate affecting a whole population

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