HASS PART 2 DESERTS AND food security

Describe the spatial distribution of hot deserts

- Located around 30°-60° latitude

- Located on almost all continents

- largest desert is the Sahara in north africa, spreading across algeria, chad, egypt, libya, mali, mauritania and parts of morocco and tunisia.

- Other deserts, such as the Gobi desert in Asia, aren't as hot as the Sahara because they are further from the equator. Deserts usually sit above or below tropical rainforests in terms of where the equator is.

Describe the rain shadow effect

1. warm, moist air is forced to rise over high areas such as a mountain

2. the air cools and condenses, forming clouds

3. rain falls

4. air descends, warms up and becomes drier over the leeward

describe the climate of a desert

- low and unreliable precipitation - averages below 250mm/yr

- when it does rain it is often a torrential downpour, which can produce rapid runoff and erosion

- extreme temperatures with large temperature changes - the annual temperature change is 20°-30°. The daily average can be over 50°.

describe soil of desert

- shallow soil, dry and too many rocks for many plant species to grow

- salty surface is caused by groundwater moving upwards by capillary action and then evaporating leaving soil crystals at the surface

- grey or red in colour as no water leaches down through the soil

describe the vegetation of a desert

-since there is little sunlight, nutrients and water, it is hard for many plant species to grow. as a result, many plants are xerophytic and sparse (scattered around, with a low-density coverage on the ground)

- low biodiversity

describe a drought evader (desert plant adaptation)

a plant that used strategies to avoid drought stress by minimising water loss

examples are lavender, russian sage, catmint and stonecrop

describe a resistor (desert plant adaptaiton)

have thick glossy leaves to reflect the heat, some can turn their leaves away from the sun e.g. desert oak and casuarinas.

some plants have a thick bark which acts as an insulator

some have shallow roots which spread over the surface to collect water or deep roots to access underground water far down

describe water conservers

plants that carefully manage and use their water to ensure it lasts for long periods of time. plant such as cacti and succculents have waxy layers which ensures moisture does not evaporate away.

halophytes describe them desert adaptation i am so tired omg

these plants are able to use the salt water instead of having to find freshwater to survive.

what biomes are used for croplands

temperate grasslands and forests

what biomes are used for pastures idk man

savvannahs, grasslands, temperate grasslands

typically staple foods are:

cheap and readily available, easily grown and accessed locally, either root vegetables or grains and can be stored easily and eaten throughout the year

describe traditional agricultiure

shifting cultivation, nomadic herding, 75% of cultivated land, found in developing countries, produced in small amounts, usually a variety of crops, low technology, more manual labor, fertilisers are natural manus, very small patches/areas of land, generally low-yeildng

describe commerical agriculture

produces commerical grain, 25% of cultivated land, found in developed countries eg australia, large amounts of food are produced, specialised productions eg just wheat or corn, high technology, uses agriccultral chemicals, low human labor, uses manufactured fertilisers, very large aras of fasmring land, yeilds high amounts for big profits