Tropical Rain Forest: -
This biome is located in the equatorial regions wherever the average annual temperature exceeds 180C and annual rainfall exceeds 140 cm. They are located primarily in south and central America north-eastern Australia, Congo river basin of Africa, Indonesia, Philippines, Hawaii and parts of Malaysia. Important characteristic feature of these biomes is very low nutrient content of the soil, except for the dead organic matter at the surface.
Structure and Function: -
The various components of a forest are as follows:
Abiotic component: -
These include basic inorganic and organic compounds present in the soil and atmosphere.
Biotic Component: -
The various biotic components, representatives from the three functional groups, of a forest ecosystem are:
(i) Producer organisms: - (AKTU. - 2010 - 11)
In a forest, the producers are mainly trees that show much species diversity and greater degree of stratification.
(ii) Consumer Organisms: - (AKTU. - 2010 - 11)
In a forest, the consumers are of three main types - primary, secondary and tertiary consumers.
The primary consumers are the herbivores which feed directly on producers. These include the smaller animals such as ants, beetles, bugs, spiders, squirrels, mice, mongooses, etc. feeding on tree leaves, and larger animals such as elephants, deer, antelops, girrafes, etc. grazing on shoots and/ or fruits of the trees (or producers).
The secondary consumers are carnivores and feed on primary consumers. These include birds, lizards, frogs, snakes, foxes, etc.
The tertiary consumers are secondary carnivores and feed on secondary consumers. These include top carnivores like lion, tiger, etc.
(iii) Decomposers: - (AKTU. - 2010 - 11)
These include a widde veriety of saprotropic microorganisms like bacteria (Sp. Bacillus, Sp. Clostridium, Sp. Pseudomonas, etc.) fungi (Sp. Aspergillus, Sp. Ganoderma, Sp. Fusarium, etc.) and actinomycetes (Sp. Streptomyces etc.). They attract the dead or decayed bodies of organisms and thus decomposition take place.
2. Aquatic Ecosystem: -
The aquatic ecosystems range from open ocean to small ponds. Aquatic ecosystems are broadly classified into fresh water and marine (ocean) ecosystems.
Rivers and Streams: -
Rivers are very important to Earth because they are major forces that shapes the landscape. Also they provide transportation and water for drinking, washing and farming. Rivers can flow on land or underground in deserts and seas. Rivers may come from mountain springs, melting glaciers or lakes.
Lakes and Ponds: -
They vary in size from a few square meter to thousands of square meters. Similarly, their depth varies from a few centimeters to over a hundred meters.
The abiotic components of ponds or lake depends on locations, latitude, altitude and the surrounding ecosystem. In some cases, the lakes may have saline or brackish water for example - Sambhar Lake of Rajasthan.
Fresh Water Biome: -
Fresh water biomes are major recreational resources but are easily polluted. Generally, animal life is abundant in fresh water biome. The open waters have many species of small invertebrate animals, collectively called zooplankton. They are both, herbivores and carnivores. Numerous species of shellfish and finfish are also found in open waters.
Fresh water biomes, thus, are economically important for their fish, for their abundant bird life and for recreation and navigation or transportation.
Ocean (Marine) Biome: -
The oceans (namely, Pacific, Atlantic, Indian, Arctic and Antarctic) cover about 70% of the earth’s surface. Each of these oceans represents a very large and stable ecosystem. Infact, as compared to fresh water, marine environments are more stable in their chemical composition due to salinity.
The biotic components of an ocean ecosystem are as follows:
1. Producers: - (AKTU. - 2010 - 11)
The primary producers are autotrophs which trap the radient energy of sun with the help of their pigments. They are mainly the phytoplanktons like the diatoms, dino flagellates and microscopic alge.
2. Consumers: - (AKTU. - 2010 - 11)
All the consumers are heterotrophic macroconsumers which feed on the primary producers. These include:
a. Primary consumers: -
These are the herbivores that include crustaceans, molluscs, fishes etc. They feed directly on producers.
b. Secondary consumers: -
These are the carnivores that feed on the herbivores (primary consumers). These are chiefly various species of fish, such as Herring, Mackerel, etc.
c. Tertiary consumers: -
These are the top carnivores that feed on other carnivores of the secondary consumers level. These are carnivorous fishes like Cod, Haddock, Shark, Whale, etc.
3. Decomposers: - (AKTU. - 2010 - 11)
These are mainly bacteria and some fungi. These micro-organisms brings about the decomposition of complex dead organic matter of producers and consumers.
