VI. Ecosystems •Ecosystem – a group of plants and animals that depend on each other and their environment for survival. • They can be very large or extremely small • can change over time due to physical processes or human activities. • for example, lack of rainfall in a temperate forest or the building of a city. A. Types of Ecosystems Tropical or Subtropical Forest •Steady hot temperatures and moist air • vast, thick areas of trees • rainfall is common Temperate Forest •Moist temperate climates support thick forests of deciduous trees. • Deciduous Trees – trees that lose their leaves in the fall. • Some temperate forests include a mix of deciduous and evergreen trees. Subarctic Forest •Coniferous Trees – trees that produce cones to carry seeds. • These trees contain needles • needles protect trees from the cold dry winters of subarctic climates. Tropical or Subtropical Grassland or Savanna •Savanna – is a park-like landscape of grasslands with scattered trees that can survive dry spells. • Savannas are found in tropical areas that have dry seasons. Temperate Grassland and Brush •Vast grasslands cover most of the region • contains more rainfall than desert ecosystems. • However, not enough rain to support forests. Mediterranean Brush •Shrubs and other low plants in Mediterranean climates hold in water. • This is to help plants survive hot, dry summers. Desert and Desert Brush •Dry semiarid areas and deserts with some rain. • support animals and low-lying desert plants. • plants need little water and can live in extreme temperatures. • driest of desert areas have little or no plant life. Mountain Grassland and Brush •Vegetation depends on elevation. • temperatures drop as altitude increases. • the higher the elevation, the fewer plant and animals there are. Tundra •The tundra is an area of cold climate and lowlying plants. • grasses grow and low shrubs bloom during brief, cool summers. • animals survive in cold temperatures with little food. Ice Cap •Thick ice caps form around the poles • year round climate of extremely cold temperatures. • no plant life exists on this ice. Global Warming?