Biology for IGCSE & O level - Variation And Selection (Section 7)
1
What does the example of the cane toad in Australia illustrate?
Answer
(A)
Natural selection can occur over a relatively short time.
2
What does the phrase "survival of the fittest" most accurately mean in the context of natural selection?
Answer
(B)
Organisms best adapted to their environment are more likely to survive and reproduce.
3
Individuals of a species of flightless sand- burrowing beetle range in colour from pale brown to almost black. The beetles have the same colour as the sand in which they live. The reason for this is likely to be:
Answer
(A)
Beetles are well camouflaged so that predators cannot see them.
4
What is the primary source of genetic variation?
Answer
(B)
Sexual reproduction and mutation.
5
Which of the following is a characteristic of discontinuous variation?
Answer
(D)
It results in distinct, separate categories.
6
What term describes the ability of an organism to survive and reproduce in its environment?
Answer
(B)
Adaptation
7
Which of the following are examples of traits that are a product of artificial selection?
Answer
B
C
D
8
What is the primary cause of mutations?
Answer
(D)
All of the above
9
What is the role of overpopulation of offspring in the context of natural selection?
Answer
(C)
Increasing the competition for survival resources.
10
In the context of evolution, what does the term 'adaptation' describe?
Answer
(B)
A characteristic that enables an organism to survive and reproduce in its environment.
11
Which of the following does natural selection act upon?
Answer
(C)
Heritable variations in a population.
12
Which of the following is a characteristic of a species that have adapted to a changing environment?
Answer
A
C
13
What does the term 'variation' describe in the context of biology?
Answer
(B)
The differences between individuals of the same species.
14
Which of the following is NOT a key difference between artificial and natural selection?
Answer
(C)
Artificial selection is generally a slow process, taking many years.
15
How does sexual reproduction contribute to genetic variation?
Answer
(C)
It shuffles the alleles of genes during meiosis and creates new combinations of alleles in fertilization.
16
In the context of natural selection, adaptation is best described as:
Answer
(B)
A process where organisms become better suited to their environment.
17
Which of the following examples best describes a process of natural selection?
Answer
(B)
A bird species evolves a longer beak to reach nectar in a flower.
18
What is the most likely outcome of a mutation in a gene that codes for an enzyme?
Answer
(C)
The protein will no longer be able to catalyze its specific reaction or will be altered.
19
What is the main function of stomata in plants adapted to desert conditions?
Answer
(B)
To allow for gas exchange while minimizing water loss.
20
Which statement best explains how changes in a population over time are influenced by natural selection?
Answer
(B)
Individuals that are better suited to their environment are more likely to survive and reproduce, passing down their beneficial traits.
21
A scientist measures the length of seashells found on a rocky shore. They collect a large sample and create a histogram of the data. Which type of variation are they most likely investigating?
Answer
(C)
Continuous variation
22
Which of the following best describes the difference between continuous and discontinuous variation?
Answer
(C)
Continuous variation is determined by multiple genes and the environment, while discontinuous variation is determined by single genes.
23
What is the relationship between genes, traits, and the environment?
Answer
(C)
Traits are typically the result of a combination of genes and the environment.
24
Which of the following is an example of discontinuous variation in humans?
Answer
(A)
Blood group
25
What is a key difference between continuous and discontinuous variations?
Answer
(A)
Continuous variation is a range, and discontinuous is distinct
26
Which term best describes the differences observed between individuals within the same species?
Answer
(B)
Variation
27
In artificial selection, who is primarily responsible for driving the evolutionary changes?
Answer
(D)
The breeder
28
Which of the following is NOT a factor that can lead to genetic variation in a population?
Answer
(C)
Selective breeding
29
What is the role of overproduction of offspring in natural selection?
Answer
(B)
To ensure there are enough individuals to compete for resources.
30
What does the term 'fitness' refer to in the context of natural selection?
Answer
(C)
An organism's ability to reproduce and pass on its genes.
31
Which of the following best describes the relationship between 'variation', 'selection', and 'adaptation'?
Answer
(B)
Variation leads to selection, and selection leads to adaptation.
32
Which type of variation is most directly influenced by environmental factors?
Answer
(D)
Phenotypic variation
33
What is the significance of heritable traits in natural selection?
Answer
(C)
They are passed down to offspring, leading to evolution.
34
Which of the following is an example of artificial selection?
Answer
(B)
The increased size of domestic sheep due to selective breeding.
35
What is a key benefit of outbreeding?
Answer
(B)
Increased hybrid vigor.
36
The table shows the results of a survey of handspans. Which of the following is an example of continuous variation?
Answer
(A)
The handspan sizes
37
Which of the following processes are examples of artificial selection?
Answer
A
B
38
What is the definition of genetic variation?
Answer
(B)
The differences in the genes of individuals.
39
Which statement best describes the role of competition in natural selection?
Answer
(B)
Competition selects against less well-adapted traits.
40
Which of the following statements best describes how natural selection leads to evolution?
Answer
(B)
Individuals with advantageous traits survive and reproduce more successfully.
41
How does the process of natural selection lead to evolution?
Answer
(C)
It favors the inheritance of traits that enhance survival and reproduction, changing the population over time.
42
What is the main difference between artificial and natural selection?
Answer
(C)
Artificial selection is driven by human choice; natural selection is driven by environmental factors.
43
What is the key difference between natural selection and artificial selection?
Answer
(C)
Artificial selection is driven by human choices.
44
Which process introduces new genetic variation into a population?
Answer
(C)
Mutation
45
What is a potential negative consequence of inbreeding, often associated with artificial selection?
Answer
(C)
Expression of harmful recessive alleles.
46
What is the key benefit of outbreeding?
Answer
(C)
Increased hybrid vigor.
47
In a population, what is the source of variation that natural selection acts upon?
Answer
(B)
Random mutations and sexual reproduction
48
What is a 'gene mutation' and what can it result in?
Answer
(A)
A physical change of a gene that can change the structure of a protein.
49
What are the requirements for successful natural selection?
