Ecosystem

Question 1

Ecosystem

Answer 1

Sum total of interaction between living (biotic) and non-living (abiotic) components capable of independent existence

Question 2

Biotic factors

Answer 2

Living elements of a habitat which affect the ability of a group of organisms to survive there

Question 3

Abiotic factors

Answer 3

Non-living factors that can determine the ability of an organism to succeed within a particular habitat

Question 4

Food chain

Answer 4

The sequence of living organisms in an ecosystem in which one organism consumes another organism to transfer food energy

Question 5

Grazing food chain

Answer 5

Living plants –> Grazing herbivores –> Carnivores

Dependent on influx of solar radiation

Question 6

Detritus food chain

Answer 6

Dead organic matter of decaying plants/animals –> Micro-organisms –> Animals feeding on detritus (detritivores)

Dependent on influx of organic matter produced in another system

Question 6

Trophic levels

Answer 6

• Trophic levels are levels or positions at which species feed
• Each step in the food chain represents a trophic level
• Represent a stepwise transfer of food and the energy contained in food

Question 7

Food web

Answer 7

Interconnected food chains operating in an ecosystem which establish a network of relationships between various species is called a food web

Question 8

What is an ecological pyramid

Answer 8

Ecological pyramids are diagrammatic representations showing the relationship between biomass, number and energy contents at different trophic levels

Question 9

Pyramid of energy

Answer 9

Shows the rate of energy flow and/or productivity at successive trophic levels

Upright

Question 10

Pyramid of numbers

Answer 10

Shows the relationship between producers and consumers at successive trophic levels in terms of their numbers

Question 11

Pyramid of biomass

Answer 11

The ecological pyramid constructed on the basis of biomass of the organisms at each trophic level is called pyramid of biomass

Question 12

Abiotic components of pond ecosystem

Answer 12

Physical environment like soil, water and air along with inorganic components

Solar input, temperature, day length and climatic conditions regulate the rate of function of the pond

Question 13

Biotic components of pond ecosystem

Answer 13

The various organisms that constitute the biotic components are producers, consumers, and decomposers

Producers: autotrophic plants e.g. Hydrilla, Vallisneria and phytoplanktons
Consumers: Heterotrophs feeding on phytoplanktons as well as living plant parts
Decomposers: heterotrophic microbes e.g. Aspergillus, Penicillium

Question 14

Productivity

Answer 14

The rate at which radiant energy is fixed in the form of an organic food due to photsynthetic and chemosynthetic activity of producers is called productivity

Question 15

GPP

Answer 15

Gross Primary Productivity

It is defined as the total rate of photosynthesis during the measurement period

Question 16

NPP

Answer 16

Net Primary Productivity

It is defined as the rate of storage of organic matter in plants in excess of the organic matter used up in respiration during the period of measurement

Also known as net assimilation

NPP = GPP - R

R- respiration

Question 17

Secondary productivity

Answer 17

Rate of storage of organic matter at consumer levels

Question 18

Decomposition

Answer 18

Process whereby decomposers breakdown complex organic matter into inorganic substances like carbon dioxide, water and nutrients

Question 19

Main steps of decomposition

Answer 19

1. Fragmentation
2. Leaching
3. Catabolism
4. Humification
5. Mineralisation

Franz Liszt Cannot Heat Mutton

Question 20

Fragmentation

Answer 20

Breakdown of detritus by detritivores into smaller particles e.g. earthworm, woodlice, maggots

Question 21

Leaching

Answer 21

Leaching is the process where water soluble inorganic nutrients go down into the soil horizon and got precipitated as unavailable salts

Question 22

Catabolism

Answer 22

Process whereby detritus is degraded into simpler inorganic substances by bacterial and fungal enzymes

Question 23

Humification

Answer 23

Accumulation of humus

Humus is highly resistant to microbial action and undergoes decomposition at an extremely slow rate. Being colloidal in nature, it serves as a reservoir of nutrients

Question 24

Mineralisation

Answer 24

The humus is further degraded by some microbes and release of inorganic nutrients occurs by the process known as mineralisation

Question 25

PAR

Answer 25

Photosynthetically Active Radiation
radiation absorbed by plants to carry out the photosynthesis process.
400 - 700 nm

Question 26

Standing crop

Answer 26

Amount of living matter present in a component population at any time in the ecosystem

Question 27

Standing state

Answer 27

Amount of inorganic substances present at any given time in the environment of an ecosystem