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Biology for IGCSE & O level - Variation And Selection (Section 2)

1
Which of the following is a key factor contributing to the struggle for survival?
Answer
(A)
Limited resources
2
What is an adaptive feature?
Answer
(C)
A feature that helps an organism survive and reproduce.
3
Which of the following statements is correct regarding inheritance in natural selection?
Answer
(D)
Only traits that are determined by genes are inherited.
4
What factor contributes most to the struggle for survival?
Answer
(B)
Overproduction of offspring.
5
What is the main difference between genetic and phenotypic variation?
Answer
(B)
Genetic variation refers to the differences in genes, while phenotypic variation refers to the physical or observable traits.
6
Which term is best defined by the statement: 'A change in the DNA base sequence of a gene'?
Answer
(B)
A change in the DNA base sequence of a gene
7
What is the main difference between inbreeding and outbreeding?
Answer
(A)
Inbreeding involves breeding closely related individuals.
8
Which of the following are necessary for evolution by natural selection to occur?
Answer
A
B
D
9
Which type of variation would describe the height of plants which grows in the same environment?
Answer
(D)
Phenotypic variation.
10
How does the environment influence the process of natural selection?
Answer
(A)
It selects which variations are advantageous.
11
Which of the following is an example of an adaptive feature found in desert plants?
Answer
(C)
Sunken stomata
12
Which of these scenarios would demonstrate discontinuous variation?
Answer
(B)
The colors of sweet pea flowers.
13
What will happen if a mutation occurs in a sex cell?
Answer
(B)
It will affect the next generation.
14
How does the environment influence phenotype?
Answer
(C)
It influences the expression of genes.
15
What is the key difference between natural selection and selective breeding?
Answer
(B)
Natural selection is driven by environmental factors; selective breeding is driven by human choice.
16
What is a potential consequence of excessive inbreeding?
Answer
(C)
Reduced vigor in offspring
17
What are the main requirements for evolution to occur through natural selection?
Answer
(B)
Inheritance, variation, and competition are needed.
18
How do the differing seed types (light vs. heavy) in the weeds contribute to their survival in a human-dominated environment?
Answer
(A)
Lighter seeds are more likely to land on concrete; heavier seeds are more likely to fall close to the parent plant.
19
What process is responsible for the development of antibiotic resistance?
Answer
(B)
Natural selection
20
In the context of weed seed dispersal, what environmental factor favors heavy seeds?
Answer
(C)
Limited open soil areas
21
What is the primary source of genetic variation in a population?
Answer
(B)
Mutation
22
What is the meaning of the term hybrid vigour?
Answer
(B)
Increase the fitness of the offspring.
23
What is a potential drawback of inbreeding?
Answer
(C)
Increased susceptibility to diseases.
24
What is a key characteristic of discontinuous variation?
Answer
(C)
It has distinct categories or groups.
25
How does antibiotic resistance in bacteria arise?
Answer
(D)
All of the above.
26
What is a gene?
Answer
(C)
A segment of DNA that codes for a trait.
27
What do scientists use to show the range of a continuous variation?
Answer
(C)
A histogram
28
What is the primary driving force behind natural selection?
Answer
(B)
Environmental factors.
29
Which of the following is an example of continuous variation?
Answer
(C)
The height of human beings
30
What type of selection would be used to describe the breeding of the Merino sheep?
Answer
(B)
Artificial selection
31
Which of the following is an example of an adaptive feature for a cactus plant in a desert environment?
Answer
(D)
Spines
32
Which of the following are examples of a desirable feature that farmers use to increase productivity with selective breeding?
Answer
A
B
C
D
33
What are the two main methods of carrying out selective breeding?
Answer
A
B
34
What are the two main types of variation that occur within a species?
Answer
(C)
Continuous and discontinuous
35
What happens during the process of natural selection?
Answer
A
B
C
36
What does overproduction of offspring lead to?
Answer
(C)
Competition for resources
37
What are the two main types of variation within a species?
Answer
(B)
Continuous and discontinuous variation
38
What is the term used to describe the increased health and vigor of offspring resulting from the outbreeding process?
Answer
(B)
Hybrid vigor
39
Which of the following is an example of discontinuous variation?
Answer
(C)
Human blood groups
40
Why is it necessary for drug companies to find and develop new types of antibiotics?
Answer
(D)
Many bacteria are resistant to some antibiotics.
41
Which of the following is a characteristic of discontinuous variation?
Answer
(A)
Individuals fall into distinct categories.
42
Which is an example of a discontinuous variation?
Answer
(C)
Human Blood Group
43
What is the primary role of mutations in the context of evolution?
Answer
(B)
To create new alleles, which can lead to genetic variation.
44
Which of the following is a key feature that farmers improve by breeders in cereal crops?
Answer
(B)
Higher yield.
45
Which of the following best describes the process of natural selection?
Answer
(B)
Organisms with advantageous traits are more likely to survive and reproduce.
46
What is the main difference between artificial and natural selection?
Answer
(B)
Artificial selection is driven by human actions, natural selection is driven by the environment.
47
Which of the following is a key characteristic of a population undergoing natural selection?
Answer
(C)
There is variation among individuals in the population.
48
What is the most accurate description of a 'gene'?
Answer
(B)
A segment of DNA that codes for a trait
49
Which of the following is a key aspect of the process of natural selection?
Answer
(B)
Environmental factors influence which traits are advantageous.
50
What causes new alleles in a gene pool?
Answer
(B)
Mutations