Syllabus Edition

First teaching 2023

First exams 2025

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Evolution & Speciation (HL IB Biology)

Exam Questions

1 hour29 questions
11 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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21 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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3
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1 mark

What is speciation?

  • The process of separating organisms into species groups.

  • The absence of gene flow between two populations.

  • The development of new species from existing species over time.

  • The exposure of two separate populations to different environmental conditions.

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4
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1 mark

Which of the following statements about selective breeding is correct?

  • Certain alleles are more likely to be passed on to offspring because they are advantageous and aid survival in an organism's environment

  • All of the offspring of the first generation are bred together to produce the second generation

  • Selective breeding is a recently developed technique

  • Crop varieties currently used by humans have been selectively bred from wild varieties

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11 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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21 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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31 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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41 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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51 mark

Why do species evolve over time?

  • To become better adapted to their environment.

  • Because of changes in the bodies of organisms.

  • Because of changes in the heritable characteristics of organisms.

  • Because certain characteristics are advantageous.

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61 mark

Which of the following must occur for speciation to take place?

  1. Two populations of a species must be separated by a mountain range or body of water.
  2. No gene exchange can take place between two populations of a species.
  3. Two populations must develop differences in their physical characteristics.
  • I and II only

  • II only

  • II and III only

  • I, II, and III

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71 mark

The image below shows a series of fossils.

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How does this set of fossils provide evidence for evolution?

  • They show the complete transition between fish and four-legged land animals.

  • They show that species change to become better adapted to their environment.

  • They strengthen the evidence for species change over time provided by the rest of the fossil record.

  • They show that limbs are always advantageous over fins.

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81 mark

The diagram below shows how selective breeding has developed several modern crop varieties from wild wheat.

The selective breeding of modern wheat from wild wheat would begin with the breeders selecting individuals with many, large seeds.

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What is the correct continuation of the process for the selective breeding of modern wheat from wild wheat?

 

Stage 1

Stage 2

Stage 3

A

Selected individuals are bred together

Offspring which produce many, large seeds are bred together

Stages 1-3 are repeated over many generations

B

Selected individuals are allowed to reproduce asexually

Offspring are allowed to mature

Stages 1-3 are repeated over many generations

C

The genes for these desirable characteristics are isolated

These desirable genes are inserted into wheat gametes

Fertilisation takes place and the plants are allowed to mature

D

Selected individuals are bred together

Offspring which produce many, large seeds are bred together

Stages 1-3 are repeated once more

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    91 mark

    Melanin is a dark pigment produced in the cells; higher melanin production results in an organism's darker colour.

    It has been noted that melanistic peppered moths have become more common than non-melanistic individuals in industrialised parts of the UK where air pollution has increased.

    Air pollution kills organisms, called lichens, that grow on the bark of trees. Areas with clean air have more lichen resulting in trees of a lighter colour compared to polluted areas where lichen are killed, causing tree trunks and branches to appear darker.

    Which of the following is not a reason for the evolution of melanism in peppered moths?

    • Predators such as birds act as a selection pressure, leading to differences in survival rates of moths with and without melanism.

    • Pollution from industry causes the death of lichens, leading to darkening of tree bark.

    • There is variation in the gene coding for melanin production in the moth population.

    • Some moths acquire darkened wings as a result of soot particles in the air, providing them with camouflage.

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    11 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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    2
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    1 mark

    The image shows the general skull structure of reptiles and mammals, as well as details of the structures inside their ears. The labels A-C indicates structures that evolutionary biologists think are equivalent to each other in both reptiles and mammals.LaGuZFue_h-1

    Which is the most likely explanation for the structures shown in the image?

    • Mammals and reptiles evolved by adaptive radiation

    • Mammals evolved from reptiles

    • Reptiles evolved from mammals

    • The jaws and ears of mammals and reptiles have evolved to be similar to each other

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    3
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    1 mark

    Several species of lava lizard of the genus Microlophus are found only in the islands of the Galapagos. A group of scientists recorded the mating displays of male lava lizards in different parts of the Galapagos, using the amplitude of a wave to represent the height and length of head bobbing behaviour. The map shows the mating displays of some male lava lizards currently living on different islands of the Galapagos.

    87283783-819e-4b6e-b44c-30a93828c162

    Which of the following statements about mating displays in Galapagos lava lizards are correct?

    I. Mating displays are the same between members of the same species of lava lizard

    II. Mating displays show continuous variation across the geographical range of the Galapagos lava lizards

    III. The mating displays suggest that lava lizards evolved by gradual divergence from a common ancestor

    IV. The mating displays recorded show all the stages of lava lizard divergence

    • I, II, and III only

    • I, II, III, and IV

    • II and III only

    • II, III, and IV only

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    4
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    1 mark

    The pelvic bones of whales are located in the equivalent position to the hip bones of land mammals, though they are not attached to the rest of the skeleton. These bones have long been thought of as vestigial structures leftover from the process of evolutionary change. Scientists researched the relationship between the size of whale pelvic bones and the size of whale testes. The graphs show some of the results of the study.

    gRYuFKnZ_h-5

    Which of the following statements relating to whale pelvic bones are correct?

    I. Whale pelvic bones are homologous to the pelvic bones of land mammals.

    II. There is no relationship between the body size of a whale, as represented by rib size, and the size of a whale's testes.

    III. The pelvic bones of whales are vestigial structures with no function.

    IV. The pelvic bones of whales are not vestigial but are involved in reproduction.

    • I and II only

    • I, II, and III only

    • I, II, and IV only

    • II and IV only

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