IBBiology: HLDPExam Questions10. Genetics & Evolution (HL Only)10.3 Gene Pools & Speciation

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First teaching 2014

Last exams 2024

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Gene Pools & Speciation (DP IB Biology: HL)

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10.3 Gene Pools & Speciation

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10.3 Gene Pools & Speciation

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11 mark

What is the definition of the term 'gene pool'? 

  • All of the genes that exist within a population

  • All of the genes and their different alleles that exist within a species

  • The different alleles that exist for one gene within a species

  • All of the genes and their different alleles that exist within a single population

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21 mark

An example of a trait that evolved by natural selection is body size in fish, which has declined with warming ocean temperatures. 

State the type of selection that this change represents. 

  • Allopatric

  • Directional

  • Disruptive

  • Stabilizing

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31 mark

Which of the following is a feature that is shared between gradualism and punctuated equilibrium? 

  • The presence of vestigial structures

  • The duration of the process

  • The occurrence of mass extinctions

  • The presence of evidence in the fossil record

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41 mark

The genus Allium has species that are used widely in agriculture. Many of these species have been bred to be polyploid. 

Which of the following is not a benefit that comes from breeding polyploid crop plants? 

  • Increases hybrid vigour

  • Reduces the risk of recessive mutations causing detrimental effects

  • When populations exist in the same area it can lead to allopatric speciation, which produces more varieties that can be sold

  • Permits novel phenotypes to be generated

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51 mark

Which of the following causes evolution?

  • Change in allele frequency over time

  • Change in the total number of alleles due to mutation

  • Change in geographic distribution

  • Change in population size

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11 mark

In humans, there are three alleles that determine blood groups, namely IO, IA and IB. The frequency of the IO allele in a particular population was found to be 0.72. There was an equal abundance of the remaining two alleles.

What would the frequency of the IB allele be in this population?

  • 0.44

  • 0.28

  • 0.14

  • 0.07

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21 mark

A game farm in South Africa has a population of about 5 000 large antelope called Kudu. Kudu bulls have large, spiralled horns which draw the attention of trophy hunters that frequently visit the game farm.

The antelope are all kept in a large, fenced-off area consisting of open grassland habitat.

Could this be considered an example of a stable gene pool?

  • No, since there will be a selective pressure to increase the allele frequency for antelope with large horns

  • No, since there will be a selective pressure for antelope with smaller horns

  • Yes, it is a large population of antelope with an equal chance to mate with each other

  • Yes, it is a large population located in a habitat that enables random matings between antelope of different phenotypes

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31 mark

Which of the following applies to the process of evolution by natural selection?

  1. Changes in the phenotype of organisms in a population
  2. Selection pressures favouring certain alleles within a population
  3. Individuals with a certain genetic makeup will not pass on their genes
  4. Changes in the allele frequencies within a population over time

  • II only

  • I, II and III

  • II and IV only

  • I, II, III and IV

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41 mark

What would be the most accurate description of the following graphs?q4_10-3_gene_pools_speciation_ib_biology_hl_mcq

 

I

II

III
A

Stabilising selection as giraffes with longer necks are selected for

Directional selection as larger and smaller turtles are selected for

Disruptive selection as cacti with a medium spine density are selected for
B

Directional selection as giraffes with longer necks are selected for

Disruptive selection as larger and smaller turtles are selected for

Stabilising selection as cacti with a medium spine density are selected for
C

Stabilising selection as giraffes with medium neck lengths are selected for

Disruptive selection as larger and smaller turtles are selected against

Directional selection as cacti with medium spine density are selected for
D

Directional selection as giraffes with medium neck lengths are selected for

Stabilising selection as larger and smaller turtles are selected against

Disruptive selection as cacti with medium spine density are selected for

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    51 mark

    What is the most important requirement for speciation to occur?

    • A geographical barrier is needed to separate different species from one another so that natural selection can occur

    • Mutations occurring within a population which brings about slight changes to the phenotype of individuals

    • Reproductive isolation must occur within a population which can be brought about by a range of different barriers

    • Organisms must be able to find a suitable mate within their habitat in order to pass on their genetic information

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    61 mark

    Which of the following would be the best description of the events depicted in the diagram?q6_10-3_gene_pools_speciation_ib_biology_hl_mcq

    • A geographical barrier separated two populations of the same species and over time they adapted to new conditions in their environment

    • A temporal barrier meant that the two populations were not able to reproduce during the same season anymore and formed new species

    • A geographical barrier separated two populations of different species and over time they adapted to seasonal differences in their habitat

    • A temporal barrier separated two populations which led to behavioural changes that resulted in speciation

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    71 mark

    A team of palaeontologists discovered the remains of an insect-like organism trapped in amber, which was found in rock layers believed to be about 180 million years old. As they dug deeper into the older layers of rock, they made several further discoveries. Their findings are shown in the diagram below.q7_10-3_gene_pools_speciation_ib_biology_hl_mcq

    What conclusion can be drawn from the information given?

    • The changes observed in these populations occurred gradually from 180 million years ago until 500 million years ago.

    • The original population changed dramatically over time which led to several different species forming

    • There were several large speciation events that occurred within a short period of time within these populations

    • Evolutionary change occurred gradually, with many small changes accumulating over a long period of time

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    81 mark

     Which of the following would not apply to the punctuated equilibrium theory of speciation?

    • A volcanic eruption on an island wipes out most individuals of a particular species of rodent

    • A change in vegetation favours field mice with a coat colour that is a deeper shade of brown

    • A bacterial colony in the human body is treated with antibiotics which kills off all susceptible individuals

    • A swarm of locusts arrive at a newly planted field containing a wheat variety that requires very robust mouth parts to bite through the leaves and stems

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    91 mark

    Why can polyploidy be considered an advantage to some plant species?

    • Meiosis can occur more rapidly, leading to an increase rate of gamete formation

    • It increases the diversity of alleles within a population and reduces the impact of recessive mutations

    • The polyploid plant can reproduce more successfully with diploid plants from the same species

    • It can lead to the occurrence of more purebred individuals within a plant population

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    101 mark

    Which of the following examples would be a useful application of comparing allele frequencies between populations?

    1. Estimating the number of individuals in a population that may be susceptible to certain diseases
    2. Studying the evolutionary history of populations within a specific species
    3. Investigating the effect of environmental factors on the phenotype within different populations

    • I only

    • III only

    • I and II only

    • I and III only

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    11 mark

    In a population of fruit flies, Drosophila melanogaster, there are several alleles that code for eye colour. 

    In one particular population there are four alleles, red, white, cherry and apricot. 

    The table below shows the allele frequencies of each of the alleles in this population. 

    Some of the data is missing. 

    Allele type Frequency
    red 0.44
    white 0.25
    cherry  
    apricot 0.18

    Which of the following statements is a correct conclusion that can be made from this data? 

    • The red eye colour allele is dominant to the rest of the eye colour alleles

    • The apricot eye colour allele is the least common allele in the population

    • Most of the fruit flies in this population show the red eye phenotype

    • The phenotype frequencies are totally unknown

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    21 mark

    Which of the following does not describe the process of natural selection? 

    • A species of antelope where the population has stronger muscles after the individuals with weak muscles are eaten by predators

    • When a bacteria is exposed to a new type of antibiotic the exposure causes the bacteria to become resistant

    • Sharks adapting to store more oxygen in their blood because the sharks with less oxygen were more likely to die

    • Dark peppered moths increasing in number during the industrial revolution in response to increased predation of the light colour moths

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    31 mark

    The three graphs below show how the allele frequencies of two alleles in three different populations changed over several generations. 10-3_q3h

    Which of the graphs show changes in allele frequency that suggest that evolution is taking place?

    • II. only

    • II. and III. only

    • III. only

    • I., II. and III. 

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    41 mark

    From the three examples listed below, which describe the occurrence of speciation?

    I. Two plant populations of the same species are pollinated by different species of insect that are active at different times of the day. There is no overlap between when the two insect species are active. Mutations occur within the two populations leading to them to become genetically distinct from each other. 

    II. A small number of lizards float on a wooden log and start a new population on another island. Mutations occur within the two populations leading to them to become genetically distinct from the original population.  

    III. A mutation occurs that causes a small population of a species of plant to become tetraploid instead of the usual diploid cells.

    • II. only

    • I. and II. only

    • I. and III. only

    • All of I., II. and III. 

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    51 mark

    Back in evolutionary history, the ancestors of giraffes used to have much shorter necks. At this time they possessed a nerve called the laryngeal nerve that travels from an area just below the brain into the brain. At this time the nerve looped under a blood vessel that was quite close to the brain and this allowed the nerve to be short and send impulses very quickly. 

    Over time as the giraffe evolved to develop a longer neck, the laryngeal nerve also grew longer. Although it still started just below the brain and sent impulses to the brain, the restriction of looping under the blood vessel near the heart prevented the nerve from avoiding growing with the neck of the giraffe. 

    The image below shows the structure of the laryngeal nerve in the giraffe.10-3_q5h

    Which of the statements below correctly describes the evolution of the giraffe laryngeal nerve?

    • The evolution of the laryngeal nerve provides evidence for the concept of punctuated equilibrium. 

    • The evolution of the laryngeal nerve is an example of stabilising selection.

    • The evolution of the laryngeal nerve provides evidence for the concept of gradualism. 

    • The evolution of the laryngeal nerve provides evidence against natural selection because natural selection would never allow for such a flawed, inefficient structure to develop.

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