A food web is more realistic than food chain for showing the feeding relationship in an ecosystem because

• it compares the number of consumers to the number of microorganisms in an ecosystem

• food chains use only a small sampling of organisms

• a food web explains why there are more producers than consumers

• producers are usually eaten by many different consumers and most consumers are eaten by more than one predator

The organisms that thrives on the remains of dead plants and animals are categorised as

• carnivore

• omnivore

• scavangers

• predators

Which of the following is false?

• The energy content in a trophic level is determined by considering individuals of a species in that trophic level

• The succession that occur in newly cooled lava is called primary success

• Rate of succession is faster in secondary succession

• Quantity of biomass in a trophic level at a particular period is called as stop-(standing) crop

Ratio between mortality and natality is called

• population ratio

• vital index

• census ratio

• density coefficient

The biomass pyramid of forest ecosystem is

• linear

• inverted

• tetra angle

• upright

Grassland with scattered trees is :

• savanna

• deciduous forest

• evergreen forest

• tropical rain forest

Living in same habitat organisms of same species from:

• biosphere

• community

• population

• niche

By anaerobic process, the cow dung is used to produce :

• methane

• butane

• ethane

• propane

129.

As insecticides reach at higher trophic level in food chain their concentration :

• increases

• become irregular

• remain constant

• decreases

The term 'ecosystem' was coined by :

• E.P. Odum

• A.G. Tansley

• Carl Mobious

• W. Clementus