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Ecosystem — BIOLOGY STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceBIOLOGYEcosystem4 Marks
Question
Differentiate between following.
✓

Answer

(a) Grazing food chain and Detritus food chain
Grazing food chainDetritus food chain
It starts from green plants-producers which are placed at first trophic level.It starts with the decomposers which degrade detritus like dead animals or fallen leaves etc.
In this food chain energy is obtained directly from sun light.In this food chain energy is derived from the decomposition of detritus material.
It is controlled by higher organisms.This is controlled by microbes.
The rate of energy flow is less.The rate of energy flow is high.
(b) Production and Decomposition
ProductionDecomposition
The food which is produced in the form of organic matter by producers is called production.Organic matter is decomposed by decomposers is called decomposition.
It depends on the photosynthesis of plants.It depends on the rate of decomposition by decomposers.
e.g. Plantse.g bacteria, fungi, earthworm
(c) Upright pyramid and Inverted pyramid
Upright pyramidInverted pyramid
In this type of pyramid, the number, biomass, energy level and productivity is higher which decreases in successive trophic level.In this type of pyramid, the number, biomass and productivity is less but at other trophic level increases.
Pyramid of energy is always upright.Pyramid of number and biomass can be inverted. e.g. dessert and polar region
At the base of pyramid there is always producers.At the base of this pyramid, the producers numbers are less.
(d) Food chain and Food web
Food chainFood web
It is the linear sequence of organisms.It forms by linkage of many food chain.
Energy flow can be easily understood.To understand energy flow is complex.
Organisms from higher trophic level only consumes one organism.One organism has many options for food.
It has simple structure.It is more complex structure.
(e) Litter and Detritus
LitterDetritus
Litter contains bio-degradable and non bio degradable things.Detritus contains only degradable matter.
e.g. leaves, metal, plastic things.Dead body or organs of organism.
(f) Primary productivity and Secondary productivity
Primary productivitySecondary productivity
Primary production is defined as the amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis.Secondary productivity is defined as the rate of formation of new organic matter by consumers.
It depends upon green plants.It depends upon heterotrophs
It has two types: gross primary productivity and net primary productivityIt has no types.
It is in a large amount.It is in a small amount.

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