All living things exist in a small portion of the Earth which supports life. ( ) Just like living things are composed of many levels which build upon each other, so to is the Biosphere a series of levels or layers. There is great diversity within the Biosphere as to the types of living things and the conditions in which they live. But there is also similarity of these areas and life forms based on global location. Regions of the Biosphere which are similar in living and nonliving factors are grouped together as BIOMES. Biomes can be either aquatic or land. We will examine the land biomes in this section. As mentioned above, biomes have living factors ( ) and nonliving factors ( ). Within each Biome, smaller areas will exist. These smaller areas can be a pond, sand dune, valley, etc. Each of these areas is called an ECOSYSTEM. Within the ecosystem there are many relationships among the living things which we will study later. Collectively this group of interrelated organisms is called a COMMUNITY. The community is composed of distinct types of organisms called POPULATIONS. Populations are made up of individual organisms which are able to interbreed and reproduce. These individual organisms are grouped together as SPECIES.