Which of the following ecosystems will be more productive in terms of primary productivity? Justify your answer. A young forest, a natural old forest, a shallow polluted lake, alpine meadow.
Primary Productivity can be defind as the rate at which primary producers (Green plants) traps and store solar radiation in form of biomass. This is measured in term of weight $\left(\mathrm{g}^{-2}\right)$ and in term of energy ( $\mathrm{Kcal} \mathrm{m}^{-2}$ ) per year in given time.
So, primary productivity varies from ecosystem to ecosystem and the ecosystem which possess more producer will be more productive in term of primary productivity. So young forest grow quicker than older, mature forest and are more productive in terms of productivity. The shallow polluted lake and alpins meadow will be less productive because of less number of producers and high amount of dead matter.
What are the three types of ecological pyramids. What information is conveyed by each pyramid with regard to structure, function and energy in the ecosystem.
Ecological Pyramids An ecological pyramid is a graphical representation of an ecological parameter as number of individual present in various trophic level of food chain.
Properties of ecological pyramid
(i) The trophic structure of an ecosystem is represented in the form of ecological pyramids.
(ii) The base of each pyramid represents the producers or the first trophic level, while the apex represents tertiary or top level consumer.
The three types of ecological pyramids are
(a) Pyramid of number shows relationship between producers and consumers in an ecosystem in terms of numbers. It may be inverted or upright pyramid.
(b) Pyramid of biomass shows relationship between producers and consumers in an ecosystem terms of biomass. It can be
(a) Upright, e.g., in case of grass land ecosystem.
(b) Inverted, e.g., in case of pond ecosystem.
Inverted pyramid of biomass.
Small standing crop of phytoplankton supports large standing crop of zooplankton
(c) Pyramid of energy is the relationship between producers and consumers in an ecosystem in terms of flow of energy. It is always upright because energy is always lost as heat at each step.
An ideal pyramid of energy. Observe that primary producers convert only $1 \%$ of the energy of the sunlight available to them into Net Primery Productivity.
Write a short note on pyramid of numbers and pyramid of biomass.
Ecological pyramids are graphical representations of the relationship between organisms of different trophic levles that can be expressed in terms of number, biomass or energy.
In most ecosystems, the pyramid of number is upright, i.e., producers are more in number than the herbivores and herbivores are more in number than the carnivores. But, the pyramid of number may be inverted as in a forest ecosystem, where the number of insects (primary consumers) are greater than the number of trees (producers).
The pyramid of biomass is upright, generally, as the biomass of producers is more than biomass of herbivores and that of herbivores is more than biomass of carnivores. But, it is inverted in ecosystems like sea ecosystem, where the biomass of fishes (primary consumers) exceeds than phytoplankton (producers).
Given below is a list of autotrophs and heterotrophs. With your knowledge about food chain, establish various linkages between the organisms on the principle of 'eating and being eaten'. What is this inter-linkage established known as?
Algae, hydrilla, grasshopper, rat, squirrel, crow, maize plant, deer, rabbit, lizard, wolf, snake, peacock, phytoplankton, crustaceans, whale, tiger, lion, sparrow, duck, crane, cockroach, spider, toad, fish, leopard, elephant, goat, Nymphaea, Spirogyra.
Food Chain and Food Web A straight line sequence of 'who eats whom' or eating and being eaten in an ecosystem is called a food chain. A network of cross connecting food chains involving producers, consumers and decomposers are termed as a food web.
Lion, Tiger - Top carnivore (Top tropic level)
Spider, cockroach, lizard, wolf, snake, toad, fish, crane - Secondry Consumer (IIIrd trophic level).
Crustaceans, grasshopper, deer, mouse, squirrel, rabbit, elephant, goat - Primary Consumer (IInd trophic level).
Phytoplankton, algae, Hydrilla, maize plant, Nymphaea, Spirogyra - Producers (Ist trophic level).
"The energy flow in the ecosystem follows the second law of thermodynamics." Explain.
According to second law of thermodynamics every activity involving energy transformation (According to first law - energy can be transferred and transformed) is accompanied by dissipation of energy as heat and only a part of it is used in building up tissues in an organisms.
This trapped energy as biomass is transferred to next trophic level. According to Lindman law only $10 \%$ of the stored energy is passed from one trophic level to successive trophic level.