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Summary Wangyanfang 107551100614 Ecology,?the?study? of the ?relationship of plants and animals to their physical and biological environment. The physical environment includes light and heat or solar radiation, moisture, wind, oxygen, carbon dioxide, nutrients in soil, water, and atmosphere. The biological environment includes organisms of the same kind as well as other plants and animals The?thin?mantle?of?life that covers the earth is called the biosphere. Several approaches are used to classify its regions. A Biomes The?broad?units?of?vegetation are called plant formations by European ecologists and biomes by North American ecologists. B Ecosystems A?more?useful?way?of?looking at the terrestrial and aquatic landscapes is to view them as ecosystems, a word coined in 1935 by the British plant ecologist Sir Arthur George Tansley to stress the concept of each locale or habitat as an integrated whole. C Energy and Nutrients Ecosystems?function?with energy flowing in one direction from the sun, and through nutrients, which are continuously recycled. Light energy is used by plants, which, by the process of photosynthesis, convert it to chemical energy in the form of carbohydrates and other carbon compounds. Energy?flow?fuels?the biogeo chemical, or nutrient cycles. D Imbalances Within?an?ecosystem?nutrients are cycled internally. But there are leakages or outputs, and these must be balanced by inputs, or the ecosystem will fail to function. Pollution If?inputs?of?any?nutrient greatly exceed outputs, the nutrient cycle in the ecosystem becomes stressed or overloaded, resulting in on. III POPULATIONS AND COMMUNITIES The?functional?units?of an ecosystem are the populations of organisms through which energy and nutrients move. A population is a group of interbreeding organisms of the same kind living in the same place at the same time. Groups of populations within an ecosystem interact in various ways. These interdependent po