| Date | November 2019 | Marks available | 2 | Reference code | 19N.2.HL.TZ0.3 |
| Level | Higher level | Paper | Paper 2 | Time zone | TZ0 / no time zone |
| Command term | Describe | Question number | 3 | Adapted from | N/A |
Question
Describe what is shown in a cladogram.
Outline how variation in organisms of the same species could lead to natural selection.
Markscheme
a. similarities/differences between organisms/species/clades ✔ mpa and mpd concern actual characteristics, not evolutionary relationships.
b. «probable» evolutionary relationships/closeness/common ancestry/phylogeny ✔ mpb concerns such relationships
c. divergence/splits/speciation/branches/nodes ✔ mpc concerns the structure branching of the cladogram
d. relative similarity/differences between base sequence/amino acid sequence ✔
a. survival of the better adapted/fittest ✔
b. more reproduction of better adapted/fittest/individuals with favorable variations ✔
c. genes for favorable variations/adaptations passed on to offspring ✔ Accept answers in the converse.
d. competition for resources/more offspring produced than the environment can support/a struggle for existence ✔ Accept answers in the converse.
Examiners report
Syllabus sections
- 18M.1.SL.TZ2.23: The figwort family is a large one consisting of many flowering plants that look similar. For...
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19M.1.SL.TZ1.23:
The DNA base sequences in a gene coding for a particular protein in four different species are shown. Locations where mutations have occurred resulting in changes to the base sequences are outlined in boxes.
[Source: © International Baccalaureate Organization 2019]
Which cladogram shows the most likely phylogenetic relationship between the four species, based on the data provided?
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22M.1.SL.TZ1.23:
Data regarding the presence (+) or absence (–) of five traits in several different species are shown in the table.
Which cladogram best represents the relationship between the five species?
- 22M.1.SL.TZ2.21: Which encircled area shows a clade?
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18M.1.SL.TZ1.23:
The cladogram was constructed using DNA base sequences from six species. Which node indicates the greatest difference in base sequences?
[Source: © International Baccalaureate Organization 2018]
- 18N.1.SL.TZ0.21: The cladogram shows the relationships of five species I to V. Which species is/are most...
- 21N.1.SL.TZ0.23: The cladogram shows one theory of how species of hominin evolved. What can be deduced...
- 18M.1.SL.TZ2.21: What reduces variation in a population? A. Meiosis B. Mutation C. Natural selection D....
- 17M.2.SL.TZ1.4a.i: State the organism most closely related to the lizards.
- 17N.1.SL.TZ0.23: The table shows the number of differences between humans and other selected organisms for the...
- 17M.1.SL.TZ2.27: The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive...
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17M.2.SL.TZ1.4a.ii:
Based on the taxa shown, deduce a difficulty in gathering data to study turtle ancestry.
- 21M.1.SL.TZ2.23: What information can be deduced from the sequence of nodes in a cladogram? A. The geological...
- 17M.1.SL.TZ1.21: Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is...
- 21M.2.SL.TZ1.5c: Cladistics and other evolutionary evidence suggest that mammals and birds have a more recent...
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16N.2.SL.TZ0.5b:
List two types of evidence used to determine which species belong in the same clade.
- 17M.2.HL.TZ1.1f.ii: Suggest a reason for the greater expression of the gene for the urea transporter after an...
- 17M.2.SL.TZ1.4b.i: Molecular evidence is often used to construct a cladogram. Describe one type of...
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19M.2.SL.TZ2.4d:
The cladogram includes four marsupial (non-placental mammal) families.
[Source: Koala image: Quartl, https://commons.wikimedia.org/wiki/Phascolarctos_cinereus#/media/
File:Friendly_Female_Koala.JPG; Wombat image: JJ Harrison, https://en.wikipedia.org/wiki/Wombat#/
media/File:Vombatus_ursinus_-Maria_Island_National_Park.jpg; Marsupial lion: Nobu Tamura,
https://en.wikipedia.org/wiki/Marsupial_lion#/media/File:Thylacoleo_BW.jpg;
Diprotodontoidea image: Anne Musser]Deduce the family that is most closely related to the Diprotodontoidea.
- 21M.2.SL.TZ1.5a.i: Based on their structure, the insect and bat wings are analogous. Outline what is meant by an...
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21M.2.SL.TZ1.5a.ii:
The bird and bat wings share homologous bone structures whereas the insect wing does not. Outline the conclusion that can be drawn about the evolution of these wings, based on homologous structures.
- 17M.2.SL.TZ1.1c: Estimate how much smaller drilled oysters raised in seawater at a high CO2 concentration were...
- 17M.3.HL.TZ1.9b: Explain what the branching off points represent in the cladogram of these fungi.
- 21M.1.SL.TZ2.21: Which evolutionary pathway is most likely to result in the evolution of analogous structures...
- 19M.2.SL.TZ2.4c: Outline the types of evidence that can be used to place a species in a particular clade.
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21M.2.SL.TZ1.5b:
Explain how cladistics can be used to investigate evolutionary relationships.
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21M.2.HL.TZ1.7c:
Outline the use of analogous and homologous traits in natural classification.
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19M.1.HL.TZ2.26:
The cladogram shows some major orders of placental mammals and is based on biochemical evidence.
[Source: © International Baccalaureate Organization 2019]
Which conclusion can be drawn from evidence in the cladogram?
A. Primates and Sirenia have not evolved from a common ancestor.
B. Primates and Cetacea do not form part of any clade.
C. Cetacea are less closely related to Sirenia than to Primates.
D. Xenarthra have not been changed by evolution for longer than other clades.
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20N.1.SL.TZ0.23:
The cladogram shows some of the groups in the three domains.
[Source: Adapted from Eric Gaba (Sting, fr:Sting), Cherkash, Public domain, via Wikimedia Commons.
https://commons.wikimedia.org/wiki/File:Phylogenetic_tree.svg.]What domains do X, Y and Z represent?
