Climate and Natural Vegetation

Question 1

Why are deserts hot and dry?

Answer 1

1. Located on the Western side of continents means that they are exposed to cool ocean currents. The low temp means that less water evaporates out to sea, meaning less rain on the desert = dry.
2. Leeward side of mountain ranges - much water lost passing over them.
3. Lack of vegetation, no water storage or evapotranspiration.
4. Lack of cloud cover - no shelter from sun
5. Area of High pressure, meaning air is sinking, less clouds formed
6. Deserts located inland, meaning air travels over large distances, therefore cannot pick up much water
7. Deserts are generally located 30 degrees N or S of equator.

Question 2

Case study of a desert? adaptations

Answer 2

SONORAN DESERT:

Saguaro cactus -No leaves meaning no water loss from transpiration. ribbed stem expands to fill with water. Spines protect from predators.
Camels - long eyelashes protect from sand, longer hair on top of camel to shade from sun.
Desert mouse - large ears allow heat to disperse heat.
Many plants die back in the hot seasons, disperse seeds only in the wet seasons.

Question 3

Define “desert”

Answer 3

Area with less than 200mm of rainfall a year (eg antarctica!!;))

Question 4

How are some plants adapted to the rain forest?

Answer 4

1. Fan palm leaves are wide so they have more access to sunlight.
2. Shallow, wide roots so they can access nutrients in thin upper fertile layer of soil.
3. Woody lianas use other trees to climb up them to access sunlight.
4. Drip-tip leaves allow water to run off the plant without damaging it.

Question 5

What are the different layers of a rain forest?

Answer 5

The bottom layer is called the forest floor, after this comes the shrub layer. Then there is the under-story followed by the canopy. Finally, there is the emerging layers.

Question 6

What is the climate of a rain forest?

Answer 6

Very wet with over 2,000 mm of rainfall per year.
Very warm with an average daily temperature of 28°C. The temperature never drops below 20°C and rarely exceeds 35°C.
The atmosphere is hot and humid.
The climate is consistent all year round.
There are no seasons.

Question 7

Case study for rain forests.

Answer 7

Borneo- Forest cleared for Bakun HEP plant. The response to deforestation was 300,000 hectares of rain forest being declared safe. The government aims to restore 900,000 hectares each year.

Question 8

Climate of a desert

Answer 8

Summer day time temperatures can exceed 40°C. However, at night the temperature can drop below 0°C.
Very few seasons.

Question 9

Factors affecting climate

Answer 9

Distance from sea:
Coastal areas are cooler and wetter than inland areas
Clouds from when warm air from inland areas meets cool sea air
Centre of continents are subject to a wide range of temperatures. In the summer temperatures can be hot and dry as moisture from the sea evaporates before it reaches the centre of the land mass

Ocean currents:
Can increase or decrease temperatures

Direction of prevailing wind:
Winds that blow from the sea often bring rain to the coast and dry weather to inland areas

Shape of the land (relief):
Mountains receive more rainfall than low lying areas because as air is forced over the higher ground it cools, causing moist air to condense and fall out as rainfall
The higher the place above sea the colder it will be because as altitude increases, air becomes thinner and is less able to absorb and retain heat

Distance from the equator:
At the poles, energy from the sun reaches the Earth’s surface at lower angles and passes through a thicker layer of atmosphere than at the equator

Human influence:
As populations increased trees were cut down in large numbers
Tree take in Carbon Dioxide and release oxygen. A reduction in trees will therefore have an affect on the amount of CO2 in the atmosphere
Invention of the motor engine and the increased burning of fossil fuels have increased the amount of CO2 in the atmosphere