| environ. |
ecosystem type Ecosystems can be classified according to various criteria: from the point of view of energy source, two major types of ecosystems can be distinguished. Autotrophic ecosystems have primary producers as a principal component and sunlight has the major initial energy source; etherotrophic ecosystems depend upon preformed organic matter that is imported from autotrophic ecosystems elsewhere. Ecosystems can also be classified in terrestrial, marine and freshwater (根据不同的标准可将生态系统进行分类：从能量的角度，可将生态系统分成两种不同的类型。自养生态系统以初级生产者为主要组成，阳光为主要能量来源；异养生态系统则依赖来自于自养生态系统中的有机物质。生态系统也可以按陆地、海洋和淡水来划分。) |
