Observation

This was not a popular question among the candidates and the performance of those who answered it was poor. Quite a good proportion of the candidates who answered the question named the following hot deserts: Sahara Desert, Arabian Desert, Iranian Desert, Kalahari Desert, Atacama Desert, Thar Desert, Californian Desert, Mohave Desert and Mexican Desert.
Some characteristics of hot deserts that were outlined included:

• high temperature (between 300C to 770C);
• annual range of temperature of about 90C to 220C;
• cloudless skies;
• high terrestrial radiation at night;
• high solar isolation during the day;
• long duration of sunshine;
• high evaporation due to high temperatures;
• relative humidity is low (about 30%);
• annual rainfall is less than 250mm;
• rainfall could be sudden and violent;
• aridity and rainlessness is common;
• days are hot and nights are cold.

The ways in which plants adapt to climatic conditions of hot desert included:

• plants are xerophytic (drought resistant) in nature;
• some plants are salt resistant;
• long roots to tap water from the ground;
• thick succulent stems to conserve water;
• leaves are small, shiny and waxy;
• some leaves are leathery and hairy;
• some plants are deciduous;
• seeds can lay dormant for a very long time;
• trees have corky barks;
• some plants have thorns or spikes for leaves.