What is meant by the term transect?
Reveal answer
A line across a habitat along which samples are taken.
Key words: transect
5(a) THE ORGANISM IN THE ENVIRONMENT · RECALL
5.4B Distribution and biodiversity using quadrats
15 recall questions · Biology only (B): not in Science (Double Award). Answer from memory, reveal the answer, then rate yourself. Ratings stay on this device.
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What is meant by the term systematic sampling?
Reveal answer
Taking samples at regular intervals.
Key words: systematic sampling
What is meant by the term correlation?
Reveal answer
A relationship in which two variables change together.
Key words: correlation
Random sampling versus transects: for Best for, give the random quadrats and the belt transect.
Reveal answer
Random quadrats: Estimating population size or comparing two areas. Belt transect: Showing change in distribution along a gradient.
Key words: Best for
Random sampling versus transects: for Quadrat placement, give the random quadrats and the belt transect.
Reveal answer
Random quadrats: Random coordinates. Belt transect: Regular intervals along a tape.
Key words: Quadrat placement
Random sampling versus transects: for Abiotic data, give the random quadrats and the belt transect.
Reveal answer
Random quadrats: Optional. Belt transect: Measured at every quadrat.
Key words: Abiotic data
Random sampling versus transects: for Main risk, give the random quadrats and the belt transect.
Reveal answer
Random quadrats: Missing patterns across a gradient. Belt transect: Bias if the transect line is chosen subjectively.
Key words: Main risk
Random sampling versus transects: for Output, give the random quadrats and the belt transect.
Reveal answer
Random quadrats: Mean per quadrat and population estimate. Belt transect: Zones of species linked to changing conditions.
Key words: Output
True or false, and why? “If a plant is more common where light is brighter, light causes the change.”
Reveal answer
False. This is a correlation. Other factors may vary along the transect, so causation needs further testing.
True or false, and why? “One transect describes the whole habitat.”
Reveal answer
False. Repeat transects are needed to show that the pattern is consistent.
True or false, and why? “Percentage cover always adds up to 100%.”
Reveal answer
False. Plants overlap in layers and bare ground exists, so totals may be above or below 100%.
What is a quadrat?
Reveal answer
A square frame of known area used to sample plants or slow-moving animals.
Key words: square frame
How do you use a transect to study the distribution of a plant?
Reveal answer
Lay a tape across the habitat → place quadrats at regular intervals → record the plant and measure an abiotic factor at each.
Key words: regular intervals
Why are quadrats placed at random when estimating a population?
Reveal answer
To avoid bias, so the sample is representative.
Key words: bias
How can percentage cover be estimated with a gridded quadrat?
Reveal answer
Count the squares more than half filled by the plant → divide by the total squares × 100.
Key words: squares