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Edexcel IGCSE Biology 4.5 Abiotic & Biotic Factors

Practise using field evidence to explain how environmental conditions, competition, disease and grazing affect populations.

Syllabus
First assessment 2019
Course
Biology 4BI1

Exam points

  • identify or control abiotic variables when comparing organism distribution
  • interpret tables or graphs to link population change with grazing, competition or disease
  • calculate percentage population change and evaluate whether data support an ecological claim

4.5 Abiotic and biotic factors question 1

[Maximum number: 5]

A group of students investigate the biodiversity in two fields, A and B.
Field A is grazed by cattle and field B has no cattle.

The students investigate the plant species in each field.

They counted the number of each species in five 0.5 m×0.5 m0.5 \mathrm{~m} \times 0.5 \mathrm{~m} quadrats.
They repeated this for each field.
Table 1 shows their results.

Table 1

Table 1

The students conclude that grazing affects the species in field A .

Using information in Table 1 and your own knowledge, discuss the students' conclusion.

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