Sustaining Ecosystems Flashcards
Polar Ecosystems (cold + dry)
Found around N + S poles
Climate - temps usually less than 10°C, winters usually less than -40°C and can reach -90°C; rain + snowfall is low (max 500mm per year); clearly defined seasons - cold summers + even colder winters
Fauna - relatively few: e.g. Polar bears, penguins, seals, whales + walruses
Flora - few plants but some lichens and mosses on rocks with some grasses + flowers on the (warmer) coast; slow-growing plants that are short
Hot Deserts (low rainfall)
Found between 15° and 35° N + S of equator
Less than 250mm per year of rainfall (v.low)
Extreme temps - hot in day to cold at night (e.g. 45°C to 0°)
Flora - Little plant growth due to lack of rainfall - plants are usually cacti or thornbushes
Plant roots are often long to reach deep water OR wide near surface to catch more water
Temperate Grasslands
Found at mid-latitudes
Climate - hot summers and cold winters (between 40°C and -40°C), 250-500mm precipitation each year (mostly in late spring - early summer)
Flora - grasses and small plants, very few trees, wide roots to absorb more water
Fauna - home to fewer animal species but mammals include bison + wild horses and rodents such as mole rats
Savannah Grasslands
Found between the tropics
Climate - quite low rainfall (800-900mm per year) + distinct wet and dry seasons, temps highest before wet season (around 35°C) and lowest after it (around 15°C)
Flora - grass, scrub and small plants + scattered trees, many plants have long roots to reach deep water or small, waxy leaves to reduce water loss
Fauna - many insects (grasshoppers, beetles etc.) and larger animals (lions, elephants, giraffes etc.)
Coral Reefs
Found mostly between 30° N + S of equator, a few miles off the coast
Climate - most common in warm areas with high sunglight, grow best in shallow, clear, salty water
Flora - few plants as it is underwater but tiny algae live inside coral + they rely on each other for nutrients
Fauna - 25% of all marine species live in coral reefs, many fish have flat bodies to swim through and hide in small gaps
Temperate Forests (mild, wet climate)
Found in mid-latitudes between tropics and polar regions
Climate - 4 distinct seasons with warm summers + cool winters, high rainfall (up to 1500mm per year)
Deciduous Forest flora - broad-leaved trees, shrubs + undergrowth, forest-floor plants
Coniferous Forest flora - evergreen trees, understory of grasses
Fauna (both) - mammals (e.g. foxes), birds, insects + ponds are homes for insects to breed which are food for fish
Tropical Rainforests (hot, wet climate)
Found around the equator
Climate - no seasons with same climate all year, hot temp (usually between 20°C and 28°C), high rainfall (around 2000mm per year) and it rains daily, usually in afternoon
Flora - evergreen trees, dense vegetation, rainforest has 4 distinct layers
Fauna - e.g. gorillas, jaguars, anacondas, tree frogs + sloths, many animals are camouflaged to hide from predators and many are nocturnal to save energy by moving when it is cooler
Water Cycle in Tropical Rainforests
- water evaporates from bodies of water + land
- water vapour is moved by winds
- water vapour condenses to form clouds then falls as rain
- water flows from one place to another (through surface run-off, soaking into ground + flowing through channels + soil) and is stored (as groundwater, in small channels or in ponds / lakes) on land
- water eventually ends up back in river / sea so cycle starts again
Nutrient Cycle in Tropical Rainforests
- dead leaves fall from evergreen trees all year round
- warm, moist climate means fungi + bacteria decompose dead matter quickly, releasing nutrients into the soil
- rainwater soaks into soil, dissolving nutrients
- nutrient-rich water is rapidly taken up by plants
Climate in Tropical Rainforests
It is always hot + evaporation rates are high as the sun is usually overhead
Lots of water vapour due to high evaporation rates so high rainfall
Dense vegetation so water is intercepted and stored by plants
Soil in Tropical Rainforests
Generally nutrient poor
Hot, wet climate results in rapid chemical weathering
Nutrients are leached down through soil making it nutrient poor
Interdependance of Tropical Rainforests
Warm, wet climate makes plants grow quickly, dense leaf cover protects forest floor, roots hold soil together
Lack of wind means that plants have to rely on bees / butterflies etc for pollination (example of symbiotic relationships which are very common in rainforests)
Many plants grow on others (epiphytes) - higher one recieves light, lower one recieves water + nutrients so they depend on each other
Deforestation reduces amound of CO2 being absorbed, adding to greenhouse effect, and changing the climate
Goods of Tropical Rainforests
Many products are sourced from rainforests (e.g. rubber, chocolate, coffee + medicines)
Hardwoods - widely used for furniture + building - logging of hardwoods can improve the country’s economy hugely
They provide opportunities for farming + mining - this creates jobs + income in many forest areas
Services of Tropical Rainforests
Home to highest diversity of plant + animal species on the planet
Rainforst plants absorb 0.7bn tonnes of CO2 yearly, reducing climate change
Risk of local flooding is reduced as water is intercepted and slowed down by dense vegetation
They help regulate global water cycle by storing water then releasing it into atmosphere slowly
Human Activity - logging
Heavy rain washes away soil if there are no roots holding soil together
Water cycle interrupted - increased risk of wildfires
Logging requires building of new roads - opens up rainforest to further development
