Ecosystems Flashcards
Statement 1: Forest, grassland, wetland and desert are some examples of terrestrial ecosystems
Statement 2: pond, lake, river and estuary are some examples of aquatic ecosystems.
Statement 1 is incorrect
Wetlands are aquatic ecosystems
Vertical distribution of different species occupying different levels is called………..
stratification
Primary production is defined as……………. And the rate of this production of biomass is referred to as………
the amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis
Productivity
………………. of an ecosystem is the rate of production of organic matter during photosynthesis.
Gross primary productivity
……………… is the available biomass for the consumption to heterotrophs
Net primary productivity
Gross primary productivity minus respiration losses (R), is the net primary productivity (NPP)
………………. is defined as the rate of formation of new organic matter by consumers.3
Secondary productivity
The annual net primary productivity of the whole biosphere is approximately ……………… (dry weight) of organic matter.
170 billion tons
Despite occupying about…………. per cent of the surface, the productivity of the oceans are only……………
70
55 billion tons
Assertion: The earthworm is referred to as the farmer’s ‘friend’.
Reason: they help in the breakdown of complex organic matter as well as in loosening of the soil
The decomposers break down complex organic matter into inorganic substances like……./……/…… and the process is called………..
carbon dioxide, water and nutrients
decomposition
The important steps in the process of decomposition are
(5)
Fragmentation
Leaching
Catabolism
Humification
Mineralisation.
Detritivores (e.g., earthworm) break down detritus into smaller particles. This process is called……….
fragmentation
By the process of…………. water-soluble inorganic nutrients go down into the soil horizon and get precipitated as unavailable salts.
leaching
Bacterial and fungal enzymes degrade detritus into simpler inorganic substances. This process is called as………
catabolism
Humification leads to accumulation of a dark coloured……….. substance called humus that is highly resistant to microbial action and undergoes decomposition at an extremely……… rate.
amorphous
slow
Being………….. in nature humus serves as a reservoir of nutrients
colloidal
The humus is further degraded by some microbes and release of inorganic nutrients occur by the process known as………….
mineralisation
The rate of decomposition is controlled by (2) factors
chemical composition of detritus
climatic factors
The decomposition rate is slower if detritus is rich in………./………. and quicker, if detritus is rich in………./………….. like sugars
lignin and chitin
nitrogen and water-soluble substances
Temperature and soil moisture are the most important climatic factors that regulate decomposition through their effects on the activities of soil microbes.
………../……….. environment favour decomposition whereas…………./……….. inhibit decomposition
Warm and moist
low temperature and anaerobiosis
Except for the ………….. ecosystem, sun is the only source of energy for all ecosystems on Earth.
deep sea hydro-thermal
Of the incident solar radiation less than……….. per cent of it is photosynthetically active radiation (PAR).
50
Plants capture only ……….. per cent of the PAR and this small amount of energy sustains the entire living world.
2-10
Assertion: Ecosystems are not exempt from the Second Law of thermodynamics.
Reason:They need a constant supply of energy to synthesise the molecules they require, to counteract the universal tendency toward increasing disorderliness.
