DP Biology (last assessment 2024)

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Question 23M.2.HL.TZ2.a

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Date May 2023 Marks available [Maximum mark: 4] Reference code 23M.2.HL.TZ2.a
Level HL Paper 2 Time zone TZ2
Command term Explain Question number a Adapted from N/A
a.
[Maximum mark: 4]
23M.2.HL.TZ2.a

Explain how observation of the fossil record provides evidence for evolution.

[4]

Markscheme
  1. fossils show the types of organisms that lived in the past;
  2. fossils can provide direct (bones/teeth/shells/leaves) or indirect (footprints/tooth marks/burrows) evidence left in layers of rocks;
  3. fossils can be dated by radioisotope dating of the rocks that hold them / the study of the different strata/sediment layers can help determine the relative age of fossils;
  4. the sequence in which fossils appear matches the sequence in which species evolved;
  5. (sequences of) fossils show (progressive) change over time / fossils show the sequence in which characteristics appear;
  6. increase in complexity of structures over time/simplest organisms longest ago;
  7. example of fossil sequence / example of increase in complexity over time;
  8. dinosaurs/trilobites/other extinct group in the fossil record suggest that organisms change over time / fossils are evidence of species that no longer exist / transition species;
  9. evidence of similar features/structures / evolution of homologous structures link existing organisms with their likely ancestors / fossils can show common ancestry / evolution of homologous structures;

Mpf: e.g. only bacteria (and no other organisms) in the oldest rocks

Mpg: e.g. sequences showing stages in development of bird wings / whales evolving from land-dwelling mammals.

Examiners report

Many vague responses were provided on how observation of fossil records would provide evidence for evolution. In general, irrelevant answers were provided and very few candidates were aware that fossils would show the types of organisms that lived in the past, or that could provide evidence of species that no longer exist or transition species. Even less responses included the idea of the possibility of fossils being dated. Very few examples of fossil sequence or examples of increased complexity over time were included.

Syllabus sections