The distribution of biomes appears to the governed by annual variation of temperature i.e. maximum and minimum temperature, mineral availability, rainfall both normal and tiniest and availability of sunlight. For instance, forests are generally associated with heavy rainfall but the type is prejudiced by temperature and light; the equivalent is true for deserts, which occur in regions where rainfall is very low.
Characteristics of some major biomes are:
Biome – Tundra:
Northern most regions adjoining the icebound poles. Similar communities at high altitudes. Devoid of all trees except stunted shrubs in the southern parts. Ground flora includes lichens, mosses and sedges. The soil is iced up for the most part but top layer melts during summer submissive a short growing season. The typical animals are reindeer, arctic fox, polar bear, snowy owl, lemming, arctic hare, ptarmigan; reptiles and amphibians more or less absent.
Mechanical scrapes, road building and oil pipelines threaten the tundras. Plants growth very deliberately in the disordered tundra, exclusively as decomposition ensures slowly in the soil.
Biome – Taiga:
Also known as, boreal forests grasp in a giant circle around northern Europe, Asia and North America but in areas of more moderate temperatures than tundra. The controlling vegetation is coniferous evergreens mostly dapper with some pine and firs. Amongst the animals are small seed eating birds and their predators such as hawks, fur-bearing carnivores, little mink, elka, puma, Siberian tiger, wolverine, wolves.
Lumbering, unfettered hunting, trapping, and agricultural development.
Biome – Temperate Deciduous Forests:
On an average, have moderate temperature & abundant rainfall nonetheless out the year. Most of the trees drop their leaves in a winter season. Extend over central and southern Europe, Eastern North America, Western China, Japan, New Zealand etc. the flora embrace trees like beach, oak, maple and cherry. Most animals are familiar vertebrates and invertebrates. These are generally the most productive agricultural areas of the earth, partly because of the controlled pace of decay and decomposition in the soil.
Agricultural activities and great human population densities have transformed most of the forests into agricultural land. Thus, very little of the original community is left.
Biome – Tropical Rain Forest:
Tropical areas of great rainfall in the equatorial regions, which abound with life expectancy. Tropical rain forests concealment only about seven percentage of the Earth’s surface but house nearby forty percent of the world’s plant and animal species. Habitat is subjugated by multiple stories of broadleaf evergreen species. Most animals & epiphytic plants are concentrated in the canopy of tree-top zones; high-temperature grades in very speedy decomposition of soil organic materials which is taken up by the plants and the nutrient pool is snarled up within the bodies of living organisms. Therefore, the soil quality is fairly pitiable.
Unfortunately, most of us never realize the incredible beauty of the tropical rain forests as these is hastily being cut down.
Biome – Savanna:
Tropical region controlled by grasses with scattered trees and fire resisting thorny shrubs. The fauna takes account of a great diversity of grazers and browsers such as antelopes, buffaloes, zebras, elephants and rhinoceros; the carnivores include lion, cheetah, hyena, mongoose, and many rodents. Savanna is most all-encompassing in Africa.
Agriculture and pressures of the human population have reduced the savanna to a great extent.
Continental interiors, with very low and sporadic rainfall with low humidity. The sun’s rays easily penetrate the atmosphere making ground temperatures very high but nights often cold by contrast. Drought resists vegetation such as cacti, euphorbia’s, sagebrush, etc. present. Animals may be numerous but mostly nocturnal. Many species of reptiles and mammal and some birds present.
Threatened in some places by irrigation and residential industrial development, irrigation frequently accentuates the already high mineral content of soil leading to salinity.
Aquatic ecosystems cover more than seventy percent of earth’s surface and are as diverse in species as the biomes. Here, we will chat characteristics features of the freshwater, marine and estuarine ecosystems that are distinguished on the basis of their salt content.
Fresh Water Ecosystem:
Freshwater ecosystems are characterized as lotic (having moving water) or lentic (unmoving water). Lotic water systems which take in fresh water streams, springs, rivulets, creaks, brooks, rivers etc. tend to become over their course from being narrow, shallow and relatively rapid to increasingly broad, deep and slow moving. Waterfalls are not infrequent features of lotic ecosystems. As would be estimated only organisms well adapted to sustaining their position in flowing water and capable of adhering to a visible surface are found in the upper reaches of a stream. Adhering organisms associated with large aquatic plants and termed periphyton.
Various types of fishes such as darters, trout, and salmon are found in mountain streams. Further, downstream we also find warm water fish, such as a catfish and carp. The maximum important primary producers of lotic systems are large but the major source of food is the organic matter brought in from the surrounding terrestrial ecosystems. Therefore nutrient levels tend to the higher downstream because there is a frequent addition of nutrients.
Lentic bodies like pools, ponds, some swamps, bogs and lakes vary considerably in physical, chemical and biological characteristics. In general, they can be considered to have three zones – littoral, limnetic and profundal. The littoral zone encompass from the shoreline to the innermost rooted plants and is dominated by floating and emergent vegetation rooted in the bottom such as reeds and cattail, water lilies and about submerged but rooted species. Frogs, snakes, snails, clams, and a considerable variety of adult insects and their larvae are also found here. The limnetic zone is the open water, down to the depth where light penetrates. This zone contains phytoplanktons that consist of diatoms, green and blue-green algae, a multiplicity of zooplanktons from protozoa to micro-arthropods. In this zone a multiplicity of grander swimming organisms, in nekton, including fish, amphibians and larger insects are also found.
The profundal zone is found below the limnetic zone and in deep lakes this zone may constitute the largest water volume of the lake. Profundal zone gets its food from the limnetic zone. This zone consists mostly of decomposers. The nekton in this zone varies with the temperature and nutrient condition.
E.p., Odum. Fundamentals of Ecology. USA: W.B Saunters Company, n.d.
Jr., Miller G.T. Living in the Environment. Belmont, California,USA: Wadsworth Publishing Company, 2003.