SECTION B: The Living World – Hot deserts
Content / Key words / skills / Case Studies & examples
Key Idea: Hot deserts ecosystems have a range of distinctive characteristics.
  1. Hot desert environment - characteristics
/ Physical characteristics, climate (hot, and very dry <250mm per year), poor soils, people. Around 30’ N and S of the equator.
Soils are sandy or stony with low nutrient levels as there are few plants.
  1. Climate
/ High pressure = air sinks = lack of rainfall as there is no rising air to make clouds = <250mm rain per year.
Low latitude so energy from sun is high intensity = very hot = over 40’C during day for months at a time in summer!
At nights deserts are very cold as no clouds to keep heat in!
  1. Plant and animal adaptations
/ Fennec fox (large ears, nocturnal, burrows), camel (stores fat in hump, can hold large amount of water etc) cactus (stores water in trunk, tap root reaches down to ground water), Californian poppy (seeds wait years for rain, grow quickly and make new seeds).
Key Idea: Development of hot desert environments creates opportunities and challenges
  1. Hot deserts- Opportunities
/ Mineral extraction (oil and gas eg.HassiMessaoud oil field in Algeria), energy (oil, gas and solar in Algeria),tourism (camel safaris, 4X4 safaris, stay with Bedouin tribes etc in Morocco), farming (growing fruit and salad items in the Nile Valley, Egypt). / Sahara desert: Algeria oil field, tourism in Morocco, farming in the Nile Valley, Egpt.
  1. Hot deserts - challenges
/ Extreme temperatures, inaccessibility (getting there and getting around – tarmac can melt on roads, sandstorms cover roads – no roads in many areas), water supply – either imported or pumped up from underground but it could runout! .
Key Idea: Areas on the fringe of hot deserts are at risk of desertification.
  1. Causes of desertification.
/ Climate change (global temperatures are going up and rainfall is less reliable.)
Population growth, removal of fuel wood (people cut down trees to burn (roots no longer hold soil = soil erosion and nutrient cycle reduced), overgrazing (cattle eat most of the grass (less roots holding onto the soil…) over-cultivation (too many crops can strip out the nutrients and the bare soil is blown away = soil erosion.),
  1. Strategies used to reduce the risk of desertification.
/ Water and soil management (use water very carefully. Make lines of stones on hills to stop water flowing down and removing soil as it goes (magic stones.)Tree planting (trees hold soil together leaves add nutrients to the soil). Use of appropriate technology (cheap and easy to mend eg. magic stones, water pumps etc). / Magic stones in Burkino Faso (lines of stones trap water and soil).
Great Green Wall in the Sahel (tree panting)