Biology for IGCSE & O level - Variation And Selection (Section 3)
1
How does the environment affect the survival of organisms?
Answer(B)
By selecting individuals with beneficial traits.
2
Which statement best describes a gene mutation?
Answer(A)
A change in a gene or chromosome.
3
Which of the following describes the correct sequence of events in natural selection?
Answer(C)
Variation - inheritance - competition - adaptation
4
In selective breeding, which of the following is the key factor for farmers to get desirable features?
5
What is the main difference between continuous and discontinuous variation?
Answer(B)
Continuous variation is due to genes and environmental factors; discontinuous variation is due to genes only.
6
In what way does a mutation in the DNA sequence affect the protein structure?
Answer(C)
It may change the amino acid sequence, leading to a different 3D shape.
7
Which of the following best describes the difference between continuous and discontinuous variation?
Answer(C)
Continuous variation shows a complete range of phenotypes, while discontinuous variation falls into a few distinct categories.
8
What does the term 'species' refer to in biology?
Answer(B)
A group of organisms capable of interbreeding and producing fertile offspring.
9
What is the role of sexual reproduction in increasing variation within a species?
Answer(B)
It creates new combinations of alleles.
10
What type of data is best visualized with a histogram?
11
In the context of the tomcod fish and PCB resistance, which process allowed the fish to adapt to the presence of PCBs?
12
What is the effect of a gene mutation?
Answer(B)
Changes the DNA sequence.
13
What is a key driving force behind natural selection?
14
What is the most likely result of overpopulation in a species?
Answer(D)
Increased competition for resources.
15
Why is the branchless stem on the Rat's Tail plant considered an adaptation?
Answer(C)
It facilitates pollination by birds.
16
What is the link between genetic variation and natural selection?
Answer(B)
Natural selection acts on existing genetic variation.
17
What is the result of natural selection?
Answer(B)
Changes in the allele frequencies over time.
18
In the context of the tomcod fish and PCB resistance, what is the role of random mutation?
Answer(B)
It provides the raw material for natural selection.
19
What will happen if a mutation occurs in a body cell?
20
Which of the following is most likely the cause of white mice appearing in a population of wild mice that typically have brown fur?
21
How does competition affect the process of natural selection?
Answer(D)
It selects for traits that enhance survival.
22
Which term is used to describe the enhanced vigor and health of offspring resulting from the outbreeding of unrelated individuals?
23
What type of variation is represented by blood groups in humans?
24
Which of the following best explains why the heavy seeds of the weed are more likely to be planted close to the parent?
Answer(C)
They tend to fall straight down to the ground.
25
What is the role of competition in natural selection?
Answer(D)
To select for the traits that improve survival and reproduction.
26
In the context of natural selection, what is meant by the term 'adaptation'?
Answer(C)
A feature that improves survival and reproduction.
27
What is a potential negative consequence of inbreeding in selective breeding?
Answer(B)
A reduction in genetic variation.
28
Which of the following is an example of a phenotype?
29
Which of the following is NOT an example of an adaptive feature?
Answer(C)
The ability of a human to digest lactose.
30
Which of the following is required for the survival of a species?
31
Which of the following statements best describes the process of outbreeding?
Answer(B)
Breeding unrelated individuals to combine good characteristics.
32
What does the term 'allele' refer to?
Answer(B)
An alternative form of a gene.
33
What term describes the differences between individuals within a species?
34
Which of the following is a direct result of natural selection?
Answer(C)
Adaptation of a population to its environment.
35
What does natural selection lead to?
Answer(C)
Changes in the characteristics of a population over time.
36
What does the term 'outbreeding' refer to in the context of selective breeding?
Answer(C)
Breeding unrelated individuals to combine desirable traits.
37
Answer(B)
Randomly or due to mutagenic factors.
38
How does mutation contribute to natural selection?
Answer(B)
By providing new variations in a population.
39
What will be the most immediate consequence if a population faces a shortage of resources?
40
What is the main process in natural selection leading to evolution?
Answer(B)
Differential survival and reproduction.
41
What is the fundamental role of mutations in the evolutionary process?
Answer(B)
To create new genetic variation.
42
What is meant by the term 'phenotype'?
Answer(B)
The observable characteristics of an organism.
43
What is the role of the environment in natural selection?
Answer(B)
To select for advantageous traits.
44
Which of the following is a key example of the role of the environment in natural selection?
Answer(A)
The development of antibiotic-resistant bacteria.
45
Which of the following are examples of continuous variation?
46
What is the key difference between continuous and discontinuous variation?
Answer(C)
Continuous variation shows a complete range of phenotypes, discontinuous variation falls into distinct categories.
47
What is the effect of natural selection?
Answer(A)
Organisms will evolve, the ones with the most advantageous features surviving.
48
What is a key difference between continuous and discontinuous variation?
Answer(C)
Continuous variation shows a range of values, discontinuous variation has distinct categories.
49
Which of the following is an example of discontinuous variation?
50
How does the structure of the Rat's Tail plant contribute to pollination by birds?
Answer(C)
The plant has a branchless stem that acts like a perch.
