Variation and Selection
Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.
Preview questions (no answers)
- 1.
When measuring the heights of 100 students, the data typically forms a bell-shaped curve. What type of variation does this represent?
A.Discontinuous variation
B.Discrete variation
C.Continuous variation
D.Qualitative variation
- 2.
What is considered the ultimate source of all new genetic variation in a population?
A.Artificial selection
B.Mutation
C.Meiosis
D.Random fertilization
- 3.
Which human characteristic is an example of discontinuous variation?
A.Body mass
B.Foot length
C.ABO blood group
D.Intelligence
Download the worksheet for Variation and Selection - Variation to practice offline. It includes additional chapter-level practice questions.
Adaptive features
SubtopicAdaptive features under Variation and Selection for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
If a specific allele provides a selective advantage to an individual in a changing environment, what is the most likely long-term effect on the population's gene pool?
A.The allele frequency will decrease as it becomes overused.
B.The frequency of that allele will increase over many generations.
C.The allele will mutate into a new form to maintain genetic diversity.
D.The allele frequency will remain constant due to Mendelian inheritance.
- 2.
Hydrophytes, such as water lilies, often possess large air spaces within their stems and leaves. What is the primary function of these air spaces?
A.To store carbon dioxide for use during the night.
B.To increase the weight of the plant to keep it anchored to the bottom.
C.To provide structural support and prevent the plant from wilting.
D.To provide buoyancy and allow for the diffusion of gases to submerged parts.
- 3.
Xerophytes are plants adapted to survive in environments with limited water. Which structural adaptation is commonly found in xerophytes to reduce water loss?
A.Large, thin leaves to increase the rate of gas exchange.
B.A reduced number of stomata located on the upper epidermis.
C.Sunken stomata that trap a layer of moist air near the leaf surface.
D.A thin, permeable waxy cuticle to facilitate cooling through evaporation.
Download the worksheet for Variation and Selection - Adaptive features to practice offline. It includes additional chapter-level practice questions.
Selection (Natural and Artificial)
SubtopicSelection (Natural and Artificial) under Variation and Selection for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
Refer to the following flowchart showing the stages of natural selection. What is the most likely outcome at 'Result X'?
A.The population becomes extinct immediately.
B.The frequency of the advantageous allele increases in the population.
C.Variation in the population is completely eliminated.
D.The environment stops changing.
- 2.
A farmer chooses to breed only the tomato plants that produce the largest fruits. This process is known as:
A.Natural selection
B.Artificial selection
C.Genetic engineering
D.Environmental adaptation
- 3.
In the context of evolution, what is the primary role of 'selection pressure'?
A.To increase the rate of mutation in a population.
B.To force organisms to learn new behaviors during their lifetime.
C.To increase the likelihood that certain individuals will survive and reproduce over others.
D.To ensure that all individuals in a population remain genetically identical.
Download the worksheet for Variation and Selection - Selection (Natural and Artificial) to practice offline. It includes additional chapter-level practice questions.