Desert Ecosystems

Question 1

What is a desert?

Answer 1

Arid areas where annual precipitation is less than 250mm (some have higher levels of rainfall but are defined by high evapotranspiration).

Question 2

What different types of deserts exist and why?

Answer 2

Hot deserts (high temperatures, low precipitation, found between 20-33° N and S), Cold deserts (hot summers, cold winters), Polar deserts (low temperatures, ice-covered), Coastal deserts (along western continental edges).

Question 3

What are xerophytes?

Answer 3

Plants adapted to dry habitats, preventing water loss (e.g. cacti, agave).

Question 4

What are ephemerals?

Answer 4

Plants that lie dormant and flower only after high rainfall.

Question 5

What is biodiversity?

Answer 5

The variety of living species on Earth, including plants, animals, bacteria, and fungi.

Question 6

Why is biodiversity low in hot deserts?

Answer 6

Extreme climate conditions limit the number of species that can survive.

Question 7

What is weathering?

Answer 7

The breakdown of rock in-situ by mechanical, biological, or chemical processes.

Question 8

What is erosion?

Answer 8

The breakdown of sediment by the movement of wind, water, ice, or rivers.

Question 9

What is deposition?

Answer 9

The release and buildup of sediment over time due to a reduction in energy.

Question 10

What is transportation in deserts?

Answer 10

The movement of sediment from one location to another.

Question 11

What is deflation?

Answer 11

The wind removes fine particles of sediment, which can be blown for thousands of miles.

Question 12

What is abrasion?

Answer 12

Sand carried by the wind wears away at rock surfaces (also known as sandblasting).

Question 13

What is attrition?

Answer 13

Particles blown by the wind collide and break apart into smaller pieces.

Question 14

What is creep in desert transportation?

Answer 14

Larger sand grains slide and roll along the surface.

Question 15

What is saltation?

Answer 15

Small sand grains skip and bounce along the surface.

Question 16

What is suspension?

Answer 16

Fine dust particles are carried by the wind within the air.

Question 17

What is mechanical weathering?

Answer 17

The physical breakdown of rocks into smaller fragments without a chemical change.

Question 18

What is biological weathering?

Answer 18

Roots from plants grow into rocks, breaking them apart.

Question 19

What is chemical weathering?

Answer 19

Moisture causes chemical reactions that break down rock.

Question 20

What is a pediment?

Answer 20

A gently sloping rock surface at the base of mountains formed by erosion and weathering from water.

Question 21

Is a pediment formed by water or wind?

Answer 21

Water.

Question 22

Is a pediment made of hard or soft rock?

Answer 22

Hard.

Question 23

What is a butte?

Answer 23

An isolated, steep-sided hill with a small, flat top formed by erosion.

Question 24

Is a butte formed by water or wind?

Answer 24

Both.

Question 25

Is a butte made of hard or soft rock?

Answer 25

Hard.

Question 26

What is a mesa?

Answer 26

A large, flat-topped hill or mountain formed by erosion of surrounding softer rock.

Question 27

Is a mesa formed by water or wind?

Answer 27

Both.

Question 28

Is a mesa made of hard or soft rock?

Answer 28

Hard.

Question 29

What is a wadi?

Answer 29

A dry riverbed or valley that fills with water only after heavy rainfall.

Question 30

Is a wadi formed by water or wind?

Answer 30

Water.

Question 31

Is a wadi made of hard or soft rock?

Answer 31

Soft.

Question 32

What is a plateau?

Answer 32

A flat, elevated landform that rises sharply above the surrounding area, formed by erosion or volcanic activity.

Question 33

Is a plateau formed by water or wind?

Answer 33

Both.

Question 34

Is a plateau made of hard or soft rock?

Answer 34

Hard.

Question 35

What is an alluvial fan?

Answer 35

A fan-shaped deposit of sediment where a fast-flowing stream spreads out and slows down.

Question 36

Is an alluvial fan formed by water or wind?

Answer 36

Water.

Question 37

Is an alluvial fan made of hard or soft rock?

Answer 37

Soft.

Question 38

What is a playa (salt pan)?

Answer 38

A dry, flat area in a desert basin that temporarily holds water after rain and leaves behind salt deposits.

Question 39

Is a playa formed by water or wind?

Answer 39

Water.

Question 40

Is a playa made of hard or soft rock?

Answer 40

Soft.

Question 41

What is an oasis?

Answer 41

A fertile area in a desert sustained by a natural water source like underground springs.

Question 42

Is an oasis formed by water or wind?

Answer 42

Water.

Question 43

Is an oasis made of hard or soft rock?

Answer 43

Soft.

Question 44

What is a barchan dune?

Answer 44

An isolated, crescent-shaped dune that forms perpendicular to the prevailing wind.

Question 45

Is a barchan dune formed by water or wind?

Answer 45

Wind.

Question 46

Is a barchan dune made of hard or soft rock?

Answer 46

Soft.

Question 47

What is desertification?

Answer 47

The process of land degradation where fertile land becomes arid and loses productivity.

Question 48

What causes desertification?

Answer 48

Factors such as unsustainable water use, overpopulation, tourism, poverty, climate change, overgrazing, and deforestation.

Question 49

How does unsustainable water management contribute to desertification?

Answer 49

Overuse of water for irrigation and urban development depletes soil moisture, leading to land degradation.

Question 50

At what scale does unsustainable water management affect desertification?

Answer 50

Local, regional, national.

Question 51

How does overpopulation contribute to desertification?

Answer 51

High demand for land and water leads to over-cultivation and deforestation, depleting soil fertility.

Question 52

At what scale does overpopulation affect desertification?

Answer 52

Regional, national, international.

Question 53

How does tourism and urbanization contribute to desertification?

Answer 53

Expanding cities and tourism facilities degrade land by redirecting natural resources.

Question 54

At what scale does tourism and urbanization affect desertification?

Answer 54

Local, regional, national.

Question 55

How does poverty and famine contribute to desertification?

Answer 55

Desperate communities overuse land for survival, worsening land degradation.

Question 56

At what scale does poverty and famine affect desertification?

Answer 56

Regional, national.

Question 57

How does climate change contribute to desertification?

Answer 57

Rising temperatures and shifting rainfall patterns reduce vegetation cover, exposing soil to erosion.

Question 58

At what scale does climate change affect desertification?

Answer 58

International.

Question 59

How does overgrazing contribute to desertification?

Answer 59

Excessive livestock grazing reduces vegetation cover, making soil vulnerable to erosion.

Question 60

At what scale does overgrazing affect desertification?

Answer 60

Local, regional.

Question 61

How does deforestation contribute to desertification?

Answer 61

The removal of trees disrupts ecosystems, reducing the land’s ability to retain moisture.

Question 62

At what scale does deforestation affect desertification?

Answer 62

Regional, national, international.

Question 63

How are deserts formed by air currents?

Answer 63

Hot air rising from the equator loses moisture as rain, then descends as dry air, creating desert conditions.