Hot Deserts: Location and Characteristics
Hot deserts are found between 15-30 degrees north and south of the equator. These regions are characterized by extreme temperatures and low rainfall, creating challenging conditions for life.
Climate and Physical Characteristics
The climate in hot deserts is marked by extreme temperature fluctuations. During the day, temperatures can soar to 45°C, while at night they can plummet to below 0°C. This dramatic variation is due to the lack of cloud cover, which allows heat to escape rapidly after sunset.
Highlight: Hot deserts receive less than 250mm of rainfall annually, contributing to their arid conditions.
The soil in hot deserts is typically infertile and dry. The scarcity of plants results in minimal leaf litter, which would otherwise enrich the soil. The low rainfall further contributes to the soil's aridity.
Plant and Animal Adaptations
Plants and animals in hot deserts have evolved remarkable adaptations to survive in these harsh environments.
Animal Adaptations
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Fennec Fox:
- Large ears help dissipate heat and detect prey beneath the sand.
- Hairy soles protect feet from hot sand.
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Camel:
- Hump stores fat for energy and water.
- Long eyelashes keep sand out of eyes.
- Wide feet prevent sinking into sand.
Example: The camel's adaptations, such as its hump for fat storage and wide feet, make it perfectly suited for desert life.
Plant Adaptations
Cacti exemplify plant adaptations in hot deserts:
- Thick, fleshy bodies (succulents) store water during dry periods.
- Thick, waxy skin reduces water loss through transpiration.
- Spines instead of leaves further minimize water loss.
Vocabulary: Transpiration is the process by which water moves through a plant and evaporates from leaves, stems, and flowers.
Desertification
Desertification is the process by which fertile land gradually turns into desert, often occurring on the borders of existing deserts.
Definition: Desertification is the degradation of land in arid, semi-arid, and dry sub-humid areas, resulting in the loss of biological productivity and complexity.
Causes and Consequences of Desertification
- Climate change: Leads to drier conditions and unreliable rainfall.
- Soil erosion: Destruction of vegetation exposes soil to wind and rain erosion.
- Overcultivation: Increased food demand exhausts soil nutrients.
- Overgrazing: Too many animals deplete limited vegetation.
- Fuelwood collection: Increased population leads to deforestation.
- Salinisation: Poor irrigation practices cause salt buildup in soil.
Highlight: Desertification can be mitigated through water and soil management techniques, including ponding banks, contour traps, and afforestation.
