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Transcript
Yr 7 ecosystems Revision sheet An ecosystem is a community of plants and animals that interact with the living (biotic) and non-living (abiotic) environment An example of an animal interacting with its environment is a wolf Food webs are diagrams that show how energy is moved around an ecosystem. The arrow goes in the direction of the energy flow. In this diagram a fox eats a bird for energy. Therefore the arrow in the diagram points from the bird to the fox (Bird Fox). Interactions with biotic factors •Eating a rabbit •Being eaten by a bear •Mating with another wolf Interactions with abiotic factors •Sleeping in a cave •Drinking water from a river •Struck by lightning A sand dune by the sea is an ecosystem. It provides a place for plants and animals to live. The shape of it protects places from strong winds, waves and flooding. They are formed when an object like a piece of drift wood or even a dead marine animal or bird is left on the beach. The object will trap sand as it is blown across the beach. Marram grass can grow in salty area so may grow on the pile of sand that we call a dune. Its roots will hold the sand together (we say they stabilise it) Over time organic matter (dead grass/poo/dead animals will mix with the sand, rot and create soil. The soil allows other plants and trees to grow and more animals will be able to live there Rainforest ecosystems There are more interactions going on in a rainforest ecosystem than any other ecosystem on Earth. In fact, an ecosystem this large is called a Biome. The weather in a rainforest is a result of the very hot weather around the equator and also due to the huge amount of transpiration that happens. Transpiration is the process of water in the trees being released into the air in the hot sunny weather. This warm wet ai rises rapidly into the sky throughout the day. It cools, condenses and clouds form. Then the rain follows! We call this convectional rainfall. If we remove the trees there will be less transpiration and therefore less rain. We won’t be able to call it a rainforest anymore. Relief RainfallRelief rainfall is where rain is caused by the height of the land. Adaptations in a rainforest Big Buttress roots grow outwards to capture nutrients that are released as dead matter on the forest floor rots away. There’s no point in sending roots down deep into the earth; the nutrients have been washed away-a process we call leaching. Deforestation-this means destroying a forest by removing the trees. Think how many species in a rainforest have an interaction with a tree. Trees are homes, hiding places, food, hunting grounds, ladders and shelter for the animals in a rainforest. Can anything survive if the trees are removed? Big Buttress roots grow outwards Before and after deforestation to capture nutrients that are released as dead matter on the forest floor rots away. There’s no point in sending roots down deep into the earth; the nutrients have been washed away-a process we call leaching. Top of a mountain= high relief Bottom of a valley= low relief Warm wet air is blown towards hills and mountains. The air is forced upwards (it can’t go through the hill!). As the warm wet air rises it cools. It is now cool wet air. The water in the air cools, condenses and clouds form. The clouds get heavy and it rain/snows. This is called precipitation. The air carries on and is now cool and drier. A rainshadow effect happens to places on the leeward side of the mountains. The air isn’t wet enough to bring them rain so their climate is much drier. Note-if you moved to Manchester you would notice that they have wetter weather than us. They live on the wetter windward side; we live on the drier leeward side of the Pennine Hills. You need to know at least three reasons why rainforests are being cut down. Can you unscramble them? 1. FRIAMGN 2. GOLGING 3. RIFE DOWO Before and after deforestation Raising awareness through campaigning Raising awareness through campaigning Relief rainfall Helping to regenerate (re-grow) an ecosystem. Rainforests are difficult. There are things that can be done but it’s difficult and the people there are hard to persuade because they are poor and want to use the forest to get richer. Sand dunes in rich countries can be regenerated by using old xmas trees to slow wind energy and build up deposits of sand. We can replant indigenous species (ones that belong there) which can be difficult or we can plant species that we know will grow well but don’t naturally belong there. Is this OK? Can you think of any problems with introducing a new species into a place? Try googling ‘history of grey squirrels in the UK’ or ‘Rabbits in Australia’ for an example