Distinguish between
a. Grazing food chain and detritus food chain
b. Production and decomposition
c. Upright and inverted pyramid
d. Food chain and Food web
e. Litter and detritus
f. Primary and secondary productivity

Explanation

a. Grazing food chain : The plant biomass is eaten by herbivores which are subsequently consumed by a variety of carnivores.
Detritus food chain : Here the food chain begins from dead bodies of animals and fallen leaves commonly termed as detritus.
b. Production refers to the process of synthesis of organic compounds from inorganic substances such as `CO_(2), H_(2)O` and minerals utlizing generally the sunlight. It is mainly done by plants.
Decomposition : The process of breaking down a substance into its constituent parts. It is brought about by reducer organisms.
c. Upright pyramid : When the number of producer organisms or their biomass is maximum in an ecosystem and these decrease progressively at each trophic level in a food chain, we get upright pyramid.
Inverted pyramid : When the number of individuals or their biomass at producer level is minimum and it increases progressively at each trophic level in a food chain, then we get inverted pyramid.
d. Food chain : The sequential inter-linking of organisms involving the transfer of food energy from the producers, through a series of organisms with repeated eating and being eaten is referred to as the food chain.
Food web is a network of food chains which become inter - connected at various trophic levels so as to form a number of feeding connections amongst different organisms of a biotic community.
e. Detritus : Dead remains of plants and animals constitute the detritus. It is differentiated into litter fall and below ground detritus.
Litter is above ground detritus. The dead remains of plants and dead remains of animals, their faecal matter that fall on the surface of earth in terrestrial ecosystem is litter.
f. Primary productivity refers to the rate of production of biomass or organic matter per unit area over a time period by the producers in an ecosystem. Secondary productivity referes to the rate of production of biomass or organic matter over a time period by the consumers.