Ecological Pyramid of Numbers

Wednesday, October 6, 2010

The Pyramid of NumbersA pyramid of numbers is a graphical representation of the numbers of individuals in each population in a food chain. Often it is drawn from the autotrophic level up. A pyramid of numbers can be used to examine how the population of a certain species affects another. Often, the autotrophic level in a pyramid of numbers is much larger than any of the higher trophic levels, and the numbers decreases upon ascending the pyramid. There are exceptions, however. For example, in a tree community, a single tree could support many different populations of larger numbers.

Wednesday, October 6, 2010

Pyramid of NumbersA diagramatic representation of the numbers of animals found in an area at ascending trophic levels of a food chain. Because only a small proportion of the energy taken in by an organism is converted to tissue and is thus available to consumers at the next trophic level, the number of organisms that can be supported at each level is generally much less than the number at the level that supplies its food

Wednesday, October 6, 2010

Pyramid of NumbersIn ecology, a diagram that shows quantities of plants and animals at different levels of a food chain. This may be measured in terms of numbers or biomass , though in terms of showing transfer of food, biomass is a more useful measure. Where biomass is measured, the diagram is often termed a pyramid of biomass. There is always far less biomass, or fewer organisms, at the top of the chain than at the bottom, because only about 10% of the food an animal eats is turned into flesh – the rest is lost through metabolism and excretion. The amount of food flowing through the chain therefore drops with each step up the chain, supporting fewer organisms, hence giving the characteristic ‘pyramid’ shape.

Wednesday, October 6, 2010

Pyramid of Numbers

In a pyramid of biomass, the primary producers are represented at the bottom by a broad band, the plant-eaters are shown above by a narrower band, and the animals that prey on them by a narrower band still. At the top of the pyramid are the few ‘top carnivores’ such as lions and sharks.

Wednesday, October 6, 2010

Pyramid of Numbers

In a pyramid of biomass, the primary producers are represented at the bottom by a broad band, the plant-eaters are shown above by a narrower band, and the animals that prey on them by a narrower band still. At the top of the pyramid are the few ‘top carnivores’ such as lions and sharks.

Wednesday, October 6, 2010

The Pyramid of NumbersThe producers are smallest sized but maximum in number while, top carnivores are larger in size but lesser in number, so these cannot be used as prey by another. Hence the pyramid of numbers is upright. When a large tree support larger number of herbivorous birds which inturn are eaten by carnivorous birds like falcon and eagle, which are smaller in number, it forms a spindle shaped pyramid.

Wednesday, October 6, 2010

The Pyramid of NumbersThe producers are smallest sized but maximum in number while, top carnivores are larger in size but lesser in number, so these cannot be used as prey by another. Hence the pyramid of numbers is upright. When a large tree support larger number of herbivorous birds which inturn are eaten by carnivorous birds like falcon and eagle, which are smaller in number, it forms a spindle shaped pyramid.

Wednesday, October 6, 2010