Hot Deserts Flashcards
What is the annual rainfall amount in hot deserts?
Less than 250 mm per year.
How often might it rain in hot deserts?
Once every few years.
What are the temperature extremes in hot deserts?
Can reach 45 °C in the day, drop below 0 °C at night.
What limits the soil’s fertility in hot deserts?
A lack of leaf fall.
What happens to the soil due to little rainfall?
The soil dries out often.
What is the texture of soil in hot deserts?
Often shallow with a gravelly texture.
What type of plants grow in hot deserts?
Sparse plants like thornbushes and cacti.
What is a characteristic of plants in hot deserts?
Plants have short life cycles, growing quickly after rain.
What adaptations do animals in hot deserts have?
Animals are adapted to the harsh environment.
What is a common characteristic of mammals in hot deserts?
Tend to be small and nocturnal.
What do most birds do during harsh conditions in hot deserts?
Leave the desert.
Which bird can live in hot deserts year-round?
Roadrunners.
Where do many people living in deserts grow crops?
Near natural water sources, usually in the desert fringes.
What is a common lifestyle of indigenous people in deserts?
Nomadic, traveling to find food and water for livestock.
What components are included in the biotic aspect of hot deserts?
Plants, animals, and people.
What are the abiotic components of hot deserts?
Climate, water, and soils.
How do plants and animals interact in hot deserts?
Plants provide nutrients and water to animals; animals spread seeds.
What effect does the hot and dry climate have on desert soils?
Soils are salty and low in nutrients due to high evaporation rates.
What limits food availability in hot deserts?
Sparse vegetation.
What can happen if cattle overgraze in hot deserts?
Soil erosion can occur.
What is a consequence of soil erosion in deserts?
Wind can blow fine sand particles into the atmosphere, forming dust clouds.
What effect do dust clouds have on rainfall in deserts?
They reduce rainfall, making deserts even drier.
What can happen to water supplies in hot deserts without rainfall?
Water supplies can dry up, affecting people, plants, and livestock.
What adaptations do desert plants have to cope with hot, dry conditions?
Desert plants have adaptations such as:
* Extremely long roots to reach deep water supplies
* Wide roots near the surface to absorb water when it rains
* Succulent stems for water storage
* Thick waxy skin to reduce transpiration
* Small leaves or spines to lower surface area and reduce transpiration.
What is an example of a plant with extremely long roots?
Mesquite roots can grow 50 m long.
What is the purpose of small leaves or spines on desert plants?
To lower their surface area and reduce transpiration.
Which plant only germinates after it rains?
Brittlebush.
What adaptations do desert animals have to cope with high temperatures?
Desert animals have adaptations such as:
* Being nocturnal to avoid heat
* Long limbs or ears for heat dissipation
* Living in underground burrows
* Storing fat that can be converted into water
* Obtaining water from food.
How do kangaroo rats minimize water loss?
Kangaroo rats do not sweat and have very concentrated urine.
What adaptations do camels have to cope with sand in the desert?
Camels have:
* Triple eyelids
* Long eyelashes
* Ability to close nostrils
* Large, flat feet.
What is the level of biodiversity in hot deserts?
Hot deserts have relatively low biodiversity.
Where is biodiversity highest in desert areas?
Around ephemeral ponds and rivers or along the desert margins.
What human activities threaten biodiversity in deserts?
Human activities that threaten biodiversity include:
* Increasing desertification
* Over-using or contaminating water supplies
* Development dividing habitats.
What impact does global warming have on desert species?
Global warming makes deserts hotter and drier, forcing some species to move to cooler areas.
What are biodiversity hotspots?
Biodiversity hotspots are places with a high proportion of endemic species that are threatened with extinction.
True or False: Desert bighorn sheep are threatened by habitat division due to roads.
True.
Fill in the blank: Many desert animals live in _______ to avoid extreme temperatures.
underground burrows.
What is desertification?
The degradation of land, making it drier and less productive.
What fraction of the world’s land is at risk of desertification?
A third of the world’s land.
What happens to soil when vegetation dies or is removed?
Exposed soil is easily removed by wind or water, leading to loss of nutrients.
Name one consequence of desertification.
The ground becomes sandy, dusty, stony, or bare rock.
What is one main cause of desertification related to climate change?
Reduced rainfall in already dry areas.
How does increased temperature contribute to desertification?
Higher temperatures cause more water to evaporate from the land.
What human activity involves the removal of trees for fuel?
Removal of fuel wood.
What is overgrazing?
Too many cattle or sheep eat plants faster than they can re-grow.
What is over-cultivation?
Planting crops in the same area continually, depleting soil nutrients.
How does population growth contribute to desertification?
More people increase pressure on land, leading to deforestation, overgrazing, and over-cultivation.
What is one strategy for reducing the risk of desertification?
Water management.
Name a crop that requires little water.
Millet, sorghum, or olives.
What is the benefit of using drip irrigation?
It prevents soil erosion by adding water gradually.
How can trees help combat desertification?
They act as windbreaks and stabilize sand.
What is soil management?
Leaving areas of land to rest and rotating crops to recover nutrients.
What is appropriate technology in the context of desertification?
Using cheap, sustainable materials for maintenance by local people.
What is one example of appropriate technology?
Sand fences or terraces.
True or False: Solar cookers help reduce the rate of deforestation.
True.
Fill in the blank: Desertification is caused by __________ and physical factors.
human
