Edexcel IAL Biology 5.14 Core Practical 11 habitat ecology

Define the sampling area, select coordinates without bias, standardise observations and record enough locations, distances or environmental values for comparison.

Exam points

Select random sample sites with a grid, coordinates and random numbers.
Plan sampling that compares locations and measures distance or abiotic variables.
Use preliminary work to choose reliable identification and observation methods.

[Maximum number: 2]

The photograph shows part of a desert in Mexico.

Figure for Question 5.14—Core Practical 11 - habitat ecology study question 1 — Edexcel A-Level Biology A2

A scientist observed that one species of cactus, Neobuxbaumia tetetzo, was often found near a species of tree, Mimosa luisana.

The scientist decided to test the hypothesis that the cactus plants often grow close to mimosa trees.

One hundred locations were selected at random. A $10 \times 10 \mathrm{~m}$ quadrat was placed at each location.

The presence or absence of each species was recorded in each quadrat.

Abiotic variables in the soil cannot be controlled in this investigation. However, these variables can be measured to confirm that these plants are growing in similar conditions.

State two abiotic variables in the soil that could affect this investigation. First variable Second variable

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5.14—Core Practical 11 - habitat ecology study question 1