ABSTRACT
This chapter deals with the distribution and patterns of life on Earth and of the underlying processes that result in these patterns. Light, temperature, moisture availability, geological factors, humans and biotic factors result in differences across the biosphere. The chapter outlines ecosystem processes including dynamic inputs of energy, cycles of nutrients and changes through time (e.g. succession, disturbance, island biogeography). Across the biosphere there are major geographical patterns with key zones known as biomes. An outline of the characteristic features of these biomes is provided. The cold biomes of the tundra and taiga have low productivity and vegetation is slow growing, restricted by short growing seasons. Irregular fire is a feature of the taiga, which can stimulate productivity. The temperate biomes of the deciduous forest, evergreen forest, Mediterranean chaparral and temperate grasslands are dominated by seasonality, with the latter two showing more adaptations to fire. The main biomes in the tropics are the highly productive and diverse tropical forests, the lower productivity savanna and the low productivity hot deserts. Savanna species often show adaptation to the regular occurrence of fire. The chapter outlines how humans have had major impacts on the biosphere through deforestation, agriculture, exploitation of species, pollution, introductions of invasive species and through creating new environments.
