环境科学交叉关系学科56章重点句词汇.doc

第五章 环境和生物间的相互作用 Interactions: Environments and Organisms The science of ecology is the study of the ways organisms interact with each other, and with their nonliving surroundings. Ecology deals with the ways in which or ganisms are adapted to their surroundings,how they make use of these surroundings, and how an area is altered by the presence and activities of organisms. All organisms are dependent on other organisms in some way. Everything that affects an organism during its lifetime is collectively known as its environment. Abiotic factors can be organized into several broad categories: energy, nonliving matter, and processes that involve the interactions of nonliving matter and energy. All organisms require a source of energy to maintain themselves. The ultimate source of energy for almost all organisms is the sun. All forms of life require atoms of elements such as carbon, nitrogen, and phosphorus, and molecules such as water to construct and maintain themselves. Organisms constantly obtain these materials from their environment. The atoms become part of an organisms body structure for a short time period, and eventually all of them are returned to the environment through respiration, excretion, or death and decay. The structure and location of the space organisms inhabit is also an important abiotic aspect of their environment. Important ecological processes involve interactions of matter and energy. The climate (average weather patterns over a number of years) of an area involves energy in the form of solar radiation interacting with the matter that makes up the Earth. The biotic factors of an organisms environment include all forms of life with which it interacts. Although organisms interact with their surroundings in many ways, certain factors may be critical to a particular species success. A shortage or absence of this factor restricts the success of the species; thus, it is known as a limiting factor. T