IB Biology SL (Standard level)- 2024 – Practice Questions- All Topics
Topic 5.1 Evidence for evolution
Topic 5 Weightage : 7%
All Questions for Topic 5.1 – Evolution, Fossil Record, Selective Breeding, Comparative Anatomy, Speciation, Evolution Example, Other Evidence, Fossilisation, Geological Time Scale, Radioactive Dating
Question
Which is an example of speciation?
Selective breeding to produce new varieties of the wheat Triticum aestivum with higher crop yield
Evolution of different courtship behaviours in separate populations of the cricket Gryllus rubens
Natural selection leading to an increase in the frequency of darker individuals of Biston betularia
Selective feeding by koalas (Phascolarctos cinereus) on Eucalyptus species.
▶️Answer/Explanation
Ans: B
The evolution of different courtship behaviors in separate populations of the cricket Gryllus rubens is an example of speciation because it represents the development of reproductive isolation between the populations. Courtship behaviors are important in crickets for attracting mates and ensuring successful reproduction. In the case of Gryllus rubens, different populations of crickets have evolved distinct courtship behaviors, such as different songs or displays, that are specific to their particular population. Over time, these populations become genetically distinct from one another due to factors such as genetic drift and natural selection. As the populations become more genetically distinct, they may become reproductively isolated from one another, meaning that they are no longer able to interbreed and produce viable offspring. This reproductive isolation is a key component of speciation, as it represents the development of two distinct species from a single ancestral population. Therefore, the evolution of different courtship behaviors in separate populations of Gryllus rubens is an example of speciation because it represents the development of reproductive isolation between the populations, which is a key component of the speciation process.
Which of these structures is not homologous?
▶️Answer/Explanation
Markscheme
C
What is the biological definition of the term evolution?
A. The changes shown by fossils over millions of years
B. The transmission of favourable variations to offspring
C. The cumulative change in the heritable characteristics of a population
D. The promotion of variation in a species by sexual reproduction
▶️Answer/Explanation
Markscheme
C
The cumulative change in the heritable characteristics of a population is the biological definition of the term evolution because it refers to the changes in the genetic makeup of a population over time that can be passed down from one generation to the next. Evolution is a biological process that occurs through the mechanisms of natural selection, genetic drift, mutation, and gene flow. These mechanisms can lead to changes in the frequency of particular traits or alleles within a population over time, which can result in the development of new traits and the emergence of new species. The key aspect of evolution is that it occurs through changes in the genetic makeup of a population that are passed down from one generation to the next. This means that the changes must be heritable, meaning that they are encoded in the DNA of the organism and can be passed down to offspring. Therefore, the cumulative change in the heritable characteristics of a population is the biological definition of the term evolution because it refers to the changes in the genetic makeup of a population over time that can be passed down from one generation to the next through the mechanisms of natural selection, genetic drift, mutation, and gene flow.
Which example provides evidence of evolution?
A. White wings of a peppered moth turn black in industrial areas.
B. Antibiotic resistant bacteria replace non-resistant bacteria over time.
C. Some Galapagos finches’ beaks become smaller during dry years.
D. Polar bears are found in warmer latitudes following global warming
▶️Answer/Explanation
Markscheme
B
Antibiotic-resistant bacteria replacing non-resistant bacteria over time is an example of evolution because it demonstrates the process of natural selection, which is one of the mechanisms of evolution. In this case, the use of antibiotics creates a selective pressure that favors the survival and reproduction of bacteria that are resistant to the antibiotics. As a result, the frequency of antibiotic-resistant bacteria increases over time, while the frequency of non-resistant bacteria decreases. This change in the frequency of traits within a population is a key aspect of evolution, as it demonstrates the process of natural selection in action. The bacteria that are resistant to antibiotics have a higher fitness than the non-resistant bacteria, as they are able to survive and reproduce in the presence of antibiotics. Over time, this process can lead to the development of new species or strains of bacteria that are highly resistant to antibiotics, which can have significant implications for human health. Therefore, the example of antibiotic-resistant bacteria replacing non-resistant bacteria over time provides strong evidence of evolution through the process of natural selection.
What is evolution?
A A measure of the relative survival and reproductive success of an individual
B. A cumulative change in the genetically controlled characteristics of a population
C. A physical change during an organism’s life that is inherited by its offspring
D. A random change in the proportions of alleles from generation to generation
▶️Answer/Explanation
Markscheme
B
A cumulative change in the genetically controlled characteristics of a population is called evolution because it refers to the gradual changes in the genetic makeup of a population over time. These changes can result from a variety of factors, including genetic drift, natural selection, mutation, and gene flow. As a result of these factors, the frequency of particular traits or alleles within a population may increase or decrease over time, leading to changes in the overall genetic makeup of the population. These changes can accumulate over generations, resulting in the development of new traits and the emergence of new species. Therefore, evolution can be defined as the process of change in the genetic makeup of a population over time, which can lead to the development of new species and the diversity of life on Earth.
Question
A short sequence of amino acids (represented by letters) in cytochrome $c$ is shown for six vertebrates. Letters in bold indicate identical amino acids for all species.
Which statement refers to this section of cytochrome c?
A. The DNA base sequences for human and rhesus monkey are different.
B. The most DNA base changes are between humans and snapping turtles.
C. The largest number of amino acid differences is two.
D. The amino acid at position 32 is the most variable.
▶️Answer/Explanation
Ans:D