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Fieldwork and sampling techniquesIB MYP Biology: Flashcards

What these 13 flashcards ask

  • Why do ecologists use sampling?
  • What is a quadrat?
  • How do you avoid bias when placing quadrats?
  • How do you calculate the mean number per quadrat?
  • What is the formula for a population estimate using quadrats?
  • What is percentage cover?
  • When is percentage cover used?
  • What is a transect?
  • When should you use a transect rather than random quadrats?
  • What is the Lincoln index?
  • Estimate the population if 50 are marked, the second sample is 40 and 10 are marked.
  • Give two assumptions of mark-release-recapture.
  • Give one way to reduce error when sampling.

Exam questions on Fieldwork and sampling techniques

  1. Students in Dubai are estimating the number of daisies on a rectangular school field that measures 40 m by 25 m. They used a 1 m² quadrat at five positions and counted 4, 7, 5, 6 and 3 daisies.
    Calculate the estimated number of daisies on the whole field.2 marks
  2. A researcher is estimating the number of ground beetles in an olive grove in Crete. In the first sample she caught 40 beetles, marked each with a tiny spot of non-toxic paint and released them. A week later she caught 36 beetles, and 9 of them carried a paint spot.
    Calculate the estimated number of ground beetles in the olive grove.2 marks
  3. Students studied a coastal sand dune in Portugal. They laid a 50 m tape from the shoreline inland and used a 1 m² grid quadrat every 10 m, estimating by eye the percentage of the ground covered by marram grass. The cover was 5% at 0 m, 15% at 10 m, 35% at 20 m, 60% at 30 m, 80% at 40 m and 90% at 50 m. They used one transect and the same student estimated every quadrat.
    Describe the trend in the cover of marram grass moving inland and give one reason why a transect was suitable for this study.3 marks
See the full worksheet

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).