Get complete information on the Parameters of the Niche

In any dimension the realised niche may be defined as we have said in terms of the set of resources exploited by an organism (or by a population of organisms) and the relative extent of use made of each of the different portions of that resource set. We can...
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Short notes on the History and Definitions of Ecological Niche

Among the first to use the term niche was Grinnell (1917, 1924, 1928). He viewed the niche as the functional role and position of an organism in its community. Grinnell considered the niche essentially a behavioural unit, although he also emphasized it as the ultimate distributional unit (thereby including...
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Short notes on Terrestrial ecosystems

Terrestrial ecosystems vary in their resilience, that is, in their ability to withstand abuse and to grow back when the abuse cases. If protected from unusual erosion and loss of seed sources, most temperate forests can support successional stages and reestablish themselves in a few ‘centuries. Grasslands seem more...
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Here is your essay on Deserts

The story of the desert has one theme-water. The distribution of water in time and space determines the nature of fragile desert ecosystems. An average rainfall of less than 25 cm (10 in.) a year will produce a desert; but each desert is different, just as are each forest...
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Short notes on Drought, Dust, and Deserts

The moderately dry climate of grasslands carries the constant risk that fluctuation in rainfall will create drought. Twenty-three separate droughts have been recorded in the Russian steppes along during the past century and a half. But the grassland community survives, because the plants are adapted to the ravages of...
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Get complete information on Bathypelagic Food Webs

The bathypelatic zone, the largest environment on earth, is cold and dark and the most deserted life zone in the ocean, both in numbers of organisms and of species. Apart from their ontogenetic migrations, the deep set ways of bathypelagic animals would seem to give them little or no...
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What are the Biological Advantages of Daily Vertical Migrations?

Modes of pelagic life are other than that elsewhere. The contrasts have been illuminated by Elton who wrote ‘…plankton has no cover structure in which predator hunts for prey, though in most other communities it seems quite likely that without such cover the community would actually collapse before long....
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What are Helminth Parasites and Immune System?

Helminths are worm-like parasites characterized by elongated, flat or round bodies. Many helminth parasites are long-lived and cause chronic infections. Within their mammalian hosts they often undergo extensive growth and differentiation with the ultimate goal of producing stages intended for transmission to the next intermediate host. Usually, the life...
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Essay on Viruses and Immune System

Viruses are small, obligate intracellular parasites which cause infection by invading cells of the body and multiplying within them. Within their life cycle they have a relatively short extracellular period, prior to infecting the cells, and a longer intracellular period during which they undergo replication. The immune system has...
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What is Immunological Tolerance to a Bacterial Antigen?

Tolerance is a property of the host in which there is an immunologically- specific reduction in the immune response to a given antigen. Tolerance to an Antigen can arise in a number of ways, but three are possibly relevant to bacterial infections. 1. Fetal exposure to Antigens: In the...
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