2.5 - Climate and Natural Vegetation Flashcards
Climate
Average weather conditions over a long period of time in a specific region
Location of hot deserts
- 15° - 30° north and south of the equator (tropical and sub-tropical)
- North Africa - Sahara, Southern Africa - Kalahari and Namib, Australia. Middle East
Annual percipitation in hot deserts
below 250 mm
Temperature range in hot deserts
- Daytime temperatures can reach 50°C but average around 25°C
- Night-time temperatures below 0°C
- Diurnal range is large up to 45°C
- Annual range is around 15°C
Seasons in hot deserts
Summer and winter
Humidity in hot deserts
Low often between 10-30%
What factors influence the climate of hot deserts?
- High pressure all year which means the air is descending and warming so precipitation does not occur because the air is not rising
- Prevailing winds are often from over land masses which means they contain little moisture
- Some deserts are in a rain shadow so there is little rainfall
- Cold ocean currents on the west side of continents may reduce summer temperatures due to the cooling effect of the ocean
Rain shadow
The prevailing wind travels across the mountains and sinks on the leewards (wind sheltered) side. This means there is no rising air and so no rainfall.
Explain the Hadley Cell
- Air rises at the equator and when it reaches the upper atmosphere it moves north and south
- The air cools and starts to sink
- This creates a zone of high pressure at about 30 degrees north and south of the equator
- Due to the sinking air, warm air cannot rise, condense and form clouds. This results in high aridity
Adaptations and their explanations of camels
- long eye lashes, hairy ears and closing nostrils help to keep out sand
- thick eyebrows which stand out and shade eyes from the sun
- wide feet so they don’t sink in the sand
- they can go without water for over a week because they can drink gallons in one go
- they can go months without food - they store fat in their humps
- body temperature can change to avoid losing water through sweating
- they are well camouflaged
- thick fur helps to keep them warm at night
Adaptations and their explanations of cacti
- thick, waxy skin to reduce loss of water and to reflect heat
- large, fleshy stems to store water
- thorns and thin, spiky or glossy leaves to reduce water loss due to their small surface area
- spikes protect cacti from animals wishing to use stored water
- deep roots to tap groundwater
- long shallow roots which spread over a wide area
- plants lie dormant for years until rain falls
Food web
System of interconnected food chains
Food chain
shows the different species of an organism in an ecosystem, and what eats what
Consumer
an animal that eats a plant or another animal
Producer
An organism that makes food. This is usually a green plant, because plants can make their own food by photosynthesis
Describe the soil profile of a hot desert
- Desert soils are thin, sandy, rocky and generally grey in colour
- Desert soils are very dry
* When it does rain they soak up the water very quickly - The surface of the soil may appear crusty. This is due to the lack of rainfall.
- As it is so hot water is drawn up to the surface of the soil by evaporation
- As the water evaporates, salts are left behind on the surface of the soil.
- There is a surface layer of sand or pebbles, with low hummus levels in it.
- This is followed by a dry brown-reddish layer, as you get deeper this contains fragments of rock.
- Then there is solid rock.
How are plants and soil interdependent in a desert climate?
- Plants rely upon soils for their nutrients
* the soils rely upon plants to provide extra nutrients through dead vegetation and fixing chemicals from the air into the soil - Plants help soils retain more water, by providing shade from the searing desert sunlight
- Plants tie the soil together, preventing soil erosion and excessive leaching of nutrients in wetter periods
- Oases exist in low points in the desert
* where water can be found closer to the surface and some agriculture is possible
What is a tropical rainforests and its characteristics (4)?
The Tropical Rainforest is a forest occurring in tropical areas of heavy rainfall.
Characteristics
* abundant with many species of wildlife and vegetation
* cover less than two percent of the Earth’s surface
* home to some 50 to 70 percent of all life forms on our planet
* are the most productive and most complex ecosystems on Earth.
Location of tropical rainforests
Tropical rainforests are located between 10°N and 10°S of the Equator
* largest rainforests are in the Amazon in Brazil (South America), Demographic Republic of Congo (Africa) and Indonesia (South East Asia) and are also found in Hawaii and the islands of the Pacific & Caribbean
Annual percipitation in tropical rainforests
over 2000 mm
Temperature range in tropical rainforests
- low range of mean monthly temperatures - 26-28°C
- Constant high temperatures
- Diurnal range is about 7 degrees celcius
Seasons in tropical rainforests
No seasons - hot and wet all year round
Humidity in tropical rainforests
High - usually over 75-80%
Explain trade winds
Winds blow into the equatorial region from high pressure areas to the north and south.
The winds from the north blow from the north-east and the winds from the south blow from the south-east
Explain convectional rainfall
When the land warms up, it heats the air above it. This causes the air to expand and rise. As the air rises it cools and condenses. If this process continues then rain will fall.
Adaptations of Lianas
These are woody vines that have roots in the ground but climb up the trees
* This is to reach the sunlight. Their leaves and flowers grow in the canopy.
Adaptations of Tree Trunks
Trunks are tall and thin
* This allows trees to reach the sunlight. The bark on these trees is smooth to allow water to flow down to the roots easily.
Adaptations of Buttress Roots
Large roots have ridges
* This creates a large surface area that help to support large trees.
Adaptations of Drip Tips
Plants have leaves with pointy tips.
* This allows water to run off the leaves quickly without damaging or breaking them.
Adaptations of Epiphytes
These are plants which live on the branches of trees high up in the canopy
* They get sunlight from the canopy while they get their nutrients from the air and water, not from the soil.
Adaptations of Sloth
The sloth uses camouflage and moves very slowly
* This makes it difficult for predators to spot.
Adaptations of Spider Monkey
The spider monkey has long, strong limbs and a prehensile tail
* This to help it to climb through the rainforest trees. To find food and escape predators
Adaptations of Flying Frogs
The flying frog has fully webbed hands and feet, and a flap of loose skin that stretches between its limbs
* This allows it to glide from plant to plant to find food and evade predators on the ground below.
Adaptations of Toucan
The toucan has a long, large bill
* This allows it to reach and cut fruit from branches that are too weak to support its weight.
Adaptations of Jaguar
They are excellent swimmers, camouflage fur and large claws
* This helps them to be an effective hunter, and climb tress to catch prey.
