An ecosystem is a biological community of interacting organisms and their physical environment. In an ecosystem, climate and soil factors influence plant growth, which provides litter and supports animal life. Key interactions between climate, soil, vegetation, and animals are represented in a systems diagram. The document then describes several major world ecosystems like tropical rainforests, hot deserts, and grasslands, characterized by differing climates, temperatures, rainfall levels, and plant and animal life.

1. Ecosystems

3. What is an ecosystem? Task Write down what you think an ecosystem is Compare your definition with a partner Write the best definition you can

4. Systems diagram Climate Soil Animals Vegetation High rainfall means that the soil becomes leached – water drains through the soil washing out minerals Thick litter layer due to high number of plants High rainfall & high temperatures all year enc plant growth Task – complete the diagram by labelling the missing arrows

5. World ecosystems Tropical rainforest – hot all year, 27-30 ºC, wet all year 2000-3000mm Hot desert – very hot above 30ºC, low rainfall below 250mm Mediterranean woodland – hot summers, 25ºC, mild winters about 18ºC. dry in summer & wet in winter, 750mm rainfall Deciduous woodland - warm summers, 18ºC, mild winters about 5ºC. 1000mm rainfall per year Coniferous forest – warm summers 16-20ºC. Very cold winters below freezing. Rainfall in summer under 500mm over year. Savanna grassland – hot all year 25-35ºC. Season of drought. 500-1000mm rain per year.