What is the definition of the term 'gene pool'?
All of the genes that exist within a population
All of the genes and their different alleles that exist within a species
The different alleles that exist for one gene within a species
All of the genes and their different alleles that exist within a single population
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An example of a trait that evolved by natural selection is body size in fish, which has declined with warming ocean temperatures.
State the type of selection that this change represents.
Allopatric
Directional
Disruptive
Stabilizing
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1 markWhich process does not generate heritable variation in a population?
Mutation
Mitosis
Metaphase I of meiosis
Fertilisation
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1 markWhich of the following statements correctly explains the process of natural selection?
I. Some species produce small numbers of young and provide higher levels of parental care
II. Advantageous alleles increase an individual's chance of surviving and reproducing
III. Individuals that change to suit their environment pass their alleles on to offspring
IV. Advantageous alleles increase in frequency in the population
I and II only
I, II, III, and IV
II, III, and IV only
II and IV only
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A game farm in South Africa has a population of about 5 000 large antelope called Kudu. Kudu bulls have large, spiralled horns which draw the attention of trophy hunters that frequently visit the game farm.
The antelope are all kept in a large, fenced-off area consisting of open grassland habitat.
Could this be considered an example of a stable gene pool?
No, since there will be a selective pressure to increase the allele frequency for antelope with large horns
No, since there will be a selective pressure for antelope with smaller horns
Yes, it is a large population of antelope with an equal chance to mate with each other
Yes, it is a large population located in a habitat that enables random matings between antelope of different phenotypes
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Which of the following applies to the process of evolution by natural selection?
I. Changes in the phenotype of organisms in a population
II. Selection pressures favouring certain alleles within a population
III. Individuals with a certain genetic makeup will not pass on their genes
IV. Changes in the allele frequencies within a population over time
II only
I, II and III
II and IV only
I, II, III and IV
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What would be the most accurate description of the following graphs?
| I | II | III |
A | Stabilising selection as giraffes with longer necks are selected for | Directional selection as larger and smaller turtles are selected for | Disruptive selection as cacti with a medium spine density are selected for |
B | Directional selection as giraffes with longer necks are selected for | Disruptive selection as larger and smaller turtles are selected for | Stabilising selection as cacti with a medium spine density are selected for |
C | Stabilising selection as giraffes with medium neck lengths are selected for | Disruptive selection as larger and smaller turtles are selected against | Directional selection as cacti with medium spine density are selected for |
D | Directional selection as giraffes with medium neck lengths are selected for | Stabilising selection as larger and smaller turtles are selected against | Disruptive selection as cacti with medium spine density are selected for |
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Which of the following examples would be a useful application of comparing allele frequencies between populations?
I. Estimating the number of individuals in a population that may be susceptible to certain diseases
II. Studying the evolutionary history of populations within a specific species
III. Investigating the effect of environmental factors on the phenotype within different populations
I only
III only
I and II only
I and III only
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Which of the following processes generate genetic variation?
I. Random assortment
II. Mitosis
III. DNA replication
IV. Random fertilisation
I and III only
I and IV only
I, III, and IV only
I, II, III, and IV
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Which of the following must occur for natural selection to take place?
Sexual reproduction.
Genetic variation.
The presence of predators.
Advantageous characteristics.
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Research was carried out on beak size in the island-living finch species Geospiza fortis. G. fortis feeds on seeds, which are plentiful, small, and soft in the years when the weather is normal, but which become larger and tougher in drought years. Some of the research results are shown in the graph below.
Which of the following statements explains the results in the graph?
Finches adapt to drought years by developing larger beaks, passing on the characteristic to their offspring, and leading to an increase in average beak size.
Average finch beak size increases during years of drought and decreases during wet years.
Average beak size increased from 9.5 mm in 1976 to 9.9 mm in 1977, before slowly decreasing to 9.7 mm by 1979.
Finches with larger beaks have an advantage when competing for food in drought years, and are therefore more likely to survive and pass on their alleles, leading to an increase in average beak size.
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In a population of fruit flies, Drosophila melanogaster, there are several alleles that code for eye colour.
In one particular population there are four alleles, red, white, cherry and apricot.
The table below shows the allele frequencies of each of the alleles in this population.
Some of the data is missing.
Allele type | Frequency |
red | 0.44 |
white | 0.25 |
cherry |
|
apricot | 0.18 |
Which of the following statements is a correct conclusion that can be made from this data?
The red eye colour allele is dominant to the rest of the eye colour alleles
The apricot eye colour allele is the least common allele in the population
Most of the fruit flies in this population show the red eye phenotype
The phenotype frequencies are totally unknown
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Which of the following does not describe the process of natural selection?
A species of antelope where the population has stronger muscles after the individuals with weak muscles are eaten by predators
When a bacteria is exposed to a new type of antibiotic the exposure causes the bacteria to become resistant
Sharks adapting to store more oxygen in their blood because the sharks with less oxygen were more likely to die
Dark peppered moths increasing in number during the industrial revolution in response to increased predation of the light colour moths
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The three graphs below show how the allele frequencies of two alleles in three different populations changed over several generations.
Which of the graphs show changes in allele frequency that suggest that evolution is taking place?
II. only
II. and III. only
III. only
I., II. and III.
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1 markIn adult humans, the ability to digest the lactose sugar in milk depends on the presence of an allele known as -13910*T. Individuals with this allele continue to produce the enzyme lactase into adulthood; this is known as lactase persistence. Individuals without this allele are not able to produce lactase after infancy and cannot digest lactose as adults. The table below shows the frequency of the -13910*T allele in European Neolithic hunter-gatherers who lived around 5 000 years ago and in modern Europeans.
| European Neolithic hunter-gatherers | Modern Europeans |
Frequency of -13910*T allele | 0.03 (+/- 0.11) | 0.74 (+/- 0.06) |
Which of the following can be concluded from the table?
There is no significant difference in the frequency of the -13910*T allele between Neolithic hunter-gatherers and modern day humans in Europe
Lactase persistence gave a survival advantage to humans at some stage between Neolithic and modern-day times
Lactase persistence gave a survival advantage to European Neolithic hunter-gatherers
Adult European Neolithic hunter-gatherers did not consume milk
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