eZine · Nigerian exams
Factors affecting the distribution of organisms
JAMB Biology topic guide with 2 practice questions.
What to revise
- abiotic factors
- biotic factors
You should be able to
- relate the effects of temperature, rainfall, relative humidity, wind speed and direction, altitude, salinity, turbidity, pH and edaphic conditions on the distribution of organisms
- use appropriate equipment (Secchi disc, thermometer, rain gauge) to measure abiotic factors
- describe how the activities of plants and animals (particularly humans) affect the distribution of organisms
From JAMB's Biology syllabus official. Full syllabus →
eZine's published bank has 7 questions on this topic (counted 29 October 2026).
Practice questions
Question 1 · Factors affecting the distribution of organisms
Vegetation on the upper slopes of the Mambilla Plateau differs from that of the surrounding lowlands mainly because, with increasing altitude,
Show answer and explanation
Answer: B. temperature falls
Temperature drops by roughly 6 °C for every 1000 m rise, so montane vegetation develops. Rainfall on highlands is often higher, not absent; soil fertility does not increase with height; day length depends on latitude, not altitude.
eZine practice question (original, teacher-reviewed)
Question 2 · Factors affecting the distribution of organisms
Few species of plants grow in the brackish mangrove swamps of the Niger Delta compared with a nearby freshwater swamp. The best explanation is that
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Answer: D. high salinity causes water loss by osmosis in most plants
Salty water is hypertonic to most plant roots, which lose water; only specially adapted mangroves tolerate it. Light is not limiting or excessive there, the soil is waterlogged not dry, and decomposers are present.
eZine practice question (original, teacher-reviewed)
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