1. UNIT 5 Ecosystems Natural Science 2. Secondary Education RIVERS

2. UNIT 5 Natural Science 2. Secondary Education Rivers Rivers are ecosystems that are defined by the movement of water. There are two different river zones: The upstream portion of the river, where there is a turbulent flow of water. Animals with more hydrodynamic shapes, which are therefore better able to swim, inhabit this area. The midstream and downstream area of the river, where animals are adapted to this zone’s characteristic warmer and slower moving water. Otters are very hydrodynamic, an adaptation to fast river currents. Perches are adapted to the slow moving water of the midstream and downstream zones.

3. Biodiversity in rivers Otter Kingfisher Dragonfly Water snake Diving beetle Trout White-throated dipper Freshwater mussel Common frog Iberian newt Caddisfly Crayfish UNIT 5 Natural Science 2. Secondary Education Rivers

4. Rivers are very important because: They are rich in biodiversity. They are a source of energy (as they can be used to produce hydroelectrical power). They deposit sediment and nutrients that help maintain coastal ecosystems. Why rivers are important Land located downstream of rivers is very fertile because of the sediments deposited by these bodies of water. UNIT 5 Natural Science 2. Secondary Education Rivers