The Living World Flashcards
What are some characteristics of hot deserts?
Very dry - below 250mm of rainfall each year
Avg daily temperatures can rise above 40C and as low as -2C at night
Minimal plant growth due to lack of rainfall
Infertile soil
How are cacti adapted to live in the desert?
Spines not leaves - minimise surface area and reduce moisture loss through transpiration
Widespread root systems - collect water from large areas
Large stem/trunk to store large amounts of water
How are kangaroo rats adapted to live in the desert?
Live in burrows during day - avoid extreme heat
Short front legs to scoop seeds
Large back legs to jump
Large ears to hear predators
Cheek pouches to store seeds
What are the threats to biodiversity in hot deserts?
Climate change - more frequent droughts and changing rainfall patterns threaten balance
Wildfires - shrubs and trees lost
Overgrazing - over cultivation leads to soil erosion
CASE STUDY (THAR DESERT) - What are the opportunities for development in the Thar desert?
Mineral extraction - limestone for cement, marble for construction, and feldspar for ceramics are all extracted from the ground
Energy - Wind and solar energy harvested in the desert due to prolonged hours of sunlight
Farming - Many subsistent farm - Gandhi canal resulted in the irrigation of 3500km2 of land for production of wheat, cotton and maize
Tourism - Desert safaris and camel rides popular - creates jobs
CASE STUDY (THAR DESERT) - What are the challenges for development in the Thar desert?
Water supply - High evaporation rates and between 120-240mm of rain per year causes low water supplies, and climate change could lead to lower rivers and more water scarcity
Inaccessibility - limited road networks, melting tarmac and sandy roads
Extreme temps - Up to more than 50C making it difficult to work and leading to high levels of evaporation
What are the causes for desertification?
Climate change - hotter and drier conditions lead to land becoming desert
Deforestation - roots cannot hold soil causing soil erosion
Overgrazing - soil becomes bare and cracked from grazing animals
Population - as it grows, demand increases causing more intensive farming and soil erosion as a result
How can we reduce the risk of desertification?
Water management - zai pits or plants that use less water help manage water levels
Tree planting - roots hold soil together to reduce erosion, provide shade to reduce rates of evaporation
Soil management - allowing land to rest after grazing allows nutrients to recover so land can be used again, crop rotation keeps nutrients in supply
Appropriate technology - cheap, sustainable and available materials locals can use such as stone lines to reduce flow of water and protect soil from erosion.
What is an ecosystem?
A natural ecosystem that includes all the biotic parts such as plants, animals and the abiotic parts such as air, sunlight and water sharing an environment
What is a biome?
A biome is a very large ecological area eg a rainforest
What affects distribution of biomes?
Altitude, climate, soil type
(higher altitudes are colder so less plants grow and less animals thrive)
What are the characteristics of a tropical rainforest?
23.5° north/south of equator
Hot and wet all year
High biodiversity
Poor soil fertility
What are the characteristics of grasslands/savannahs?
Between 5 and 15° north/south of equator
low rainfall
Hot with a wet and dry season
Mainly grass, scrub and specially adapted plants eg acacia
What are the characteristics of a Desert?
15-30° north/south of equator
Located in belt of high pressure and low rainfall
Less than 250mm of rain a year
High daytime temp (eg 45°C) and low night time (eg 0°C)
(CASE STUDY) What are the impacts of deforestation in Malaysia?
Trees (global) can no longer take in carbon dioxide, and is also released when trees are burned for fuel
Loss of biodiversity (global)- species can become endangered or extinct due to habitat destruction (34.9% reduction in species richness in oil palm compared to rainforest)
Decline of indigenous tribes (local) tribes are stripped of land and are more exposed to illness
Soil erosion - without tree roots, soil becomes loose and vulnerable, prone to soil erosion, and nutrients are washed away by the rain
What are the positives/negatives of deforestation for Malaysia’s economy?
In 2020, palm oil accounted for 38% of the value of Malaysia’s agricultural output. Palm oil industries employ 441,000 people.
Illegal logging creates around $10-15 billion annually in criminal proceeds
How can we reduce deforestation?
-Selective logging and replanting
-Conservation and education
-Ecotourism
-International agreements
-Debt reduction
What are some examples of biotic factors?
-Decomposers
-Insects
-Plants
-Animals
What are some examples of abiotic factors?
-Sun
-Rain
-Wind
-Soil
What is a biome?
A large scale ecosystem, with similar climate and landscapes
What are the characteristics of tropical rainforests?
-Close to equator
-High temp
-High rainfall
-Low air pressure
covers 6% of world’s population but has over half of worlds known species
-23.5° north/south of equator
-Infertile soil
What are characteristics of deserts?
-Found 15 to 30 degrees North and South of the equator
(Close to tropics of Capricorn and Cancer)
-High air pressure
-High daytime temp (eg 45°C) and low night time (eg 0°C)
-Less than 250mm of rainfall annually
What are characteristics of a tropical grassland?
-Dry and wet seasons caused by movement of Hadley cells
-Dry season is very hot - fires
-Wet season is very wet - floods
-Large herds of animals
What are characteristics of temperate grasslands?
-Moderate rainfall, mild conditions
-Away from coast
-Hot summers
-Cold winters
