A biome or phytogeographic area is a community of organisms, plants (flora) and animals (fauna) that inhabit a certain region of planet Earth, with their own climatic characteristics.
Biomes do not have a clearly defined boundary. On the contrary, one biome gradually mixes with another. The areas between biomes are called ecotones. For example, the shores of beaches are ecotonic regions because they are between an ocean biome and a terrestrial biome.
There are biomes around the globe and they differ from one another, mainly due to their physiognomy or visual characteristics, climatic conditions and especially their vegetation. The latter is an essential component of biomes, since the consumers and decomposers that inhabit them depend on it.
The culminating vegetation type (grasses, conifers, deciduous trees) is uniform in each biome, but a particular species of plant may be different in different parts of the biome. The class of culminating vegetation depends on the physical environment, and this and that determine the type of animals present.
The definition of biome includes not only the dominant community of the region, which has reached a high level of stability in its interactions with the environment; but also includes the intermediate communities that precede it, and that are still unstable from the point of view of their interaction with the environment.
The different biomes are divided into three types: terrestrial biomes, freshwater biomes and marine biomes . Terrestrial biomes are the most varied, and marine biomes contain much more dissolved salts than freshwater biomes.
Terrestrial biomes are distributed, albeit more or less irregularly, like strips around the world. In this way, if a person observes its distribution from the Equator to the North Pole, they find tropical forests with a rainy climate, tropical savannas, deserts, temperate prairies, chaparral, deciduous forests, coniferous forests and ends in the biome of the tundra in northern Canada and Alaska.
Freshwater biomes (freshwater) can be divided into two types; biome of still or lentic waters, such as lakes and ponds; and biome of running or lotic waters, such as the waters of rivers and streams. The marine biomes characterized by the oceans, two varieties can be found; the littoral or neritic biome, and the oceanic or pelagic biome.
