AQA Geography: Living World

Ecosystems - answer-An ecosystem is a unit of all living, and non-living parts in an area. These parts are classed as producers, consumers, or decomposers. A Producer - answer-An organism that uses sunlight energy to produce food. A Consumer - answer-An organism that gets its energy from eating other organisms; eating producers or other consumers. A Decomposer - answer-An organism that gets its energy by breaking down dead material like dead producers or consumers e.g bacteria or fungi. The Nutrient Cycle - answer-When dead material is decomposed, nutrients are released into the soil, which are then taken up from the soil by plants, that can be eaten by consumers, creating a nutrient cycle. Food Chains - answer-A food chain shows what eats what in an ecosystem and how energy is passed through an ecosystem. Food Webs - answer-A food web shows lots of different food-chains and how they overlap each other. Where are Tropical Rainforests found? - answer-They are found around the equator. Where are Temperate Deciduous Forests found? - answer-They are found between 40 and 60 north and south of the equator where there's four distinct seasons. Where are Hot Deserts found? - answer-They are found 15 and 30 north and south of the equatior where there's less rainfall. World Ecosystems - answer-Different parts of the world have different ecosystems because they have different climates. Tropical Rainforests - answer-Found in areas like Central America, the Amazon, and Central Africa. They have a Hot, Wet climate with no definite seasons. Soil and Vegetation structure of Tropical Rainforests - answer-The soil isn't very fertile as heavy rain washes nutrients away. There are nutrients at the surface due to decayed leaf fall but this layer is very thin because decay is fast in warm, moist conditions. Three layers and a shrub layer going up by 10m each layer. The Shrub layer is nearest to the ground (10m) and gets very little light. Then there is the Undercanopy layer (20m). Then the Canopy layer which is a continuous layer of trees around 30m high. Then finally the Emergent layer which has the highest trees (40m) that poke out of the canopy layer and only have branches at their crown where the most light reaches them. Plant Adaptations in Tropical Rainforests - answer-Plants have adapted to the heavy rainfall by having thick, waxy leaves that have pointed tips (called drip-tips) that channel the water to a point so it runs off. This way the weight of the water doesn't damage the plant. Tall trees have big roots called buttress roots to support the weight of their trunks in the very shallow soil, and stops ephiphytes from bringing them down. Ephiphytes grow on trees and they don't need roots in the soil as they share the nutrients with the host Fan palms have large fan-shaped leaves that are good for catching sunlight and water. These are found in the canopy. Hot Deserts - answer-Found in areas like North Africa, the Middle East, and large parts of Australia where there's very little rainfall and when it does rain, it varies a lot, as it may only rain once every two or three years. Temperatures are extreme, ranging from very hot in the day (e.g 45C) to very cold at night (e.g 5C). Soil and Vegetation Structure in Hot Deserts - answer-The soil is usually shallow with a coarse, gravelly texture. There's hardly any leaf fall so the soil isn't very fertile. Plant growth is very sparse due to very little rainfall, and the plants that do grow include cacti and thornbushes. Plant Adaptations in Hot Deserts - answer-Plant roots are either extremely long to reach very deep water supplies, or shallow and spread out widely to catch as much water as possible from rainfall.