(Question and Answers)

ENVIRONMENT

Quest. What is environment?

The environment is defined as the sum of total of all the living and non-living things around us influencing one another.

Quest. Define environmental science. 

Environmental science is the study of the environment, its biotic (biological) and abiotic (non-biological) components and their interrelationship.

Quest. What are the important components of environment?

a. Abiotic or Non-living component
b. Biotic or Living component
c. Energy component

Quest. What are the functions of lithosphere?

a. It is home for human beings and wildlife
b. It is storehouse of minerals and organic matters

Quest. Explain biosphere. 

The part of lithosphere, hydrosphere and atmosphere in which living organisms live and interact with one another is called biosphere.

Quest. State the significance and scope of environmental education.

Significance

1. Environmental studies inform the people about their effective role in protecting the environment by demanding changes in laws and enforcement system.
2. Environmental studies have a direct relation to the quality of life we live.
3. Environmental studies develop a concern and respect for the environment.

Quest. What is environmental resistance?  

Factors in an environment such as predators, competition, climate and food availability, that keep its various population from reaching their maximum growth potential is known as environmental resistance.

Scope

1. To get an awareness and sensitivity to the total environment and its related problems.
2. To motivate the active participation in environmental protection and improvement.

Quest. State the need for public awareness for solving environmental problems.

Environmental pollution cannot be removed by the laws alone.The proper implementation and especially public participation are the important aspects, which should be given importance and stress. The public participation is useful in law making process and controlling the pollution activities. Thus the public participation plays a major role in the effective environmental management.

 ECOSYSTEM

Quest. What is ecology?

Ecology is the study of interaction among organisms or group of organisms with their environment. The environment consists of both biotic and non-biotic components.

Quest. Explain the concept of an ecosystem. 

A group of organism interacting among them and with the environment is known as the concept of ecosystem. An ecosystem may be natural like a pond, a lake, a river, an ocean, or a forest or it may be man made like an aquarium.

Quest. What are the components of ecosystem?

a.. Abiotic or Non-living component

b. Biotic or Living component

Quest. How are biotic components grouped?

The members of biotic components of an ecosystem are grouped into three groups based on how they get their food.

a. Producers
b. Consumer
c. Decomposers

Quest. What are autotrophic and heterotrophic components of an ecosystem? Give examples

1.  Autotrophic components: The members of autotrophic components are producers, which are autotrophs(self- nourishing organisms). They derive energy from sunlight and make organic compounds from inorganic substances.
   Examples: Green plants, algae, bacteria, etc.,
2.  Heterotrophic components: The members of heterotrophic components are consumers and decomposers, which are heterotrophs (dependent on others for food). They consume the autotrophs (Producers)

The heterotrophs are

(a) Macro consumers: They are herbivores, carnivores (or) omnivores.

(b) Saprotrops: They are decomposers (bacteria, fungi, etc.)

Quest. Define the terms producers and consumers. 

1.  Producers synthesize their food themselves through photosynthesis.
2.  Consumers are organisms which cannot prepare their own food and depends directly or indirectly on the producers.

Quest. Define primary production and secondary production.  

Primary production of an ecosystem is defined as the conversion of radiant energy into organic substances by photosynthesis by the primary producers (Plants)

Secondary production of an ecosystem is defined as distribution of energy in the form of food to the consumer (or) the energy stored by the consumer.

Quest. How does a biome differs from an ecosystem. 

The kind or organisms which can live in a particular ecosystem depends on their physical and metabolic adoptions to the environment of that place. On earth there are many sets of ecosystems which are exposed to same climatic conditions and having dominant species with similar life cycle, climatic adoptions and physical structure. This set of ecosystem is called a biome.

Quest. What are nutrient cycles?

The cyclic flow of nutrients between the biotic and abiotic components is known as nutrient cycle or biochemical cycles.

Quest. What is hydrological cycle?

ANSWER: Movement of water in a cyclic manner is known as the hydrological cycle

Quest. What is ecological succession?

The progressive replacement of one community by another till the development of stable community in a particular area is called ecological succession.

Quest. What is food chain? 

ANSWER: The sequence of eating and being eaten in an ecosystem is known as food chain.

Quest. What are tropical levels (or) feeding levels?

ANSWER: The various steps through which food energy passes in an ecosystem is called as tropic levels.

Quest. What is food web?  

ANSWER: The interlocking pattern of various food chains in an ecosystem is known as food web.

Quest. What is Ecological pyramids?

Graphical representation of structures and function of tropic levels of an ecosystem, staring with producers at the bottom and each successive tropic levels forming the apex is known as an ecological pyramids.

Quest. Name any four ecosystems.  

a. Forest ecosystems
b. Grassland ecosystems
c. Desert ecosystems
d. Aquatic ecosystems

Quest. What are the characteristics of desert ecosystem?  

1. The desert air is dry and the climate is hot.
2. Annual rainfall is less that 25cm.
3. The soil is very poor in nutrients and organic matter.
4. Vegetation is poor.

Quest. What is meant by keystone species?  

Within a habitat each species connects to and depends on other species. But, while each species contribute to habitat functioning, some species do more than others in the over all scheme of things. Without the work of these key species, the habitat changes significantly.
These species are called keystone species. When a keystone species disappears form its habitat, that habitat changes drastically.

Quest. What are the types of grassland ecosystem? 

There are three types of grassland ecosystem based on the climate condition.

1. Tropical grassland

2. Temperate grassland

3. polar grassland

Quest. What are food chains? Mention their type.

The sequence of eating and being eaten in an ecosystem is known as food chain.

1. Grazing food chain
2. Detritius food chain

Quest. What are the abiotic components of an ecosystem?

The nonliving components (physical and chemical) of an ecosystem collectively form a community called abiotic community.

Quest. Differentiate food chain and food web.  

Food chain : The sequence of eating and being eaten in an ecosystem is known as food chain
Food web: If one species gets affected or become extinct, then the species in the subsequent tropic level are also affected. The interlocking pattern of various food chains in an ecosystem is known as food web.

BIODIVERSITY

Quest. Define Biodiversity and its significance.  

Biodiversity is defined as the variety and variability among all groups of living organisms and the ecosystem in which they occur.

Significance:

a. Biodiversity is very important for human life, as we depend on plants, micro- organisms, earth‟s animals for our food, medicine and industrial products.
b. Biodiversity is also important for forestry, fisheries and agriculture, which depend on rich variety of various biological resources available in nature.
c. Biodiversity protects the fresh air, clean water and productive land.

d. Loss of biodiversity has serious economic and social costs for any country.

Quest. Explain the classification of biodiversity.

Biodiversity is generally classified into three types

Genetic diversity, Species diversity and Ecosystem diversity

Quest. Define genetic diversity and species diversity.

Genetic diversity is the diversity within species ie., variation of genes within the species and the diversity between different species.The sum of varieties of all the living organisms at the species level is known as species diversity.

Quest. What are the two important biodiversity hot spots in India?

1.Eastern Himalayas

2.Western Ghats

Quest. What are the criteria for recognizing hot spots?  

(1) The Richness of the endemic species is the primary criterion for recognizing hot spots
(2) The hot spots should have a significant percentage of specialized species.
(3) The site is under threat.
(4) It should contain important gene pools of plants of potentially useful plants.

 Quest. What is the need of biodiversity conservation?

a. It provides immediate benefits to the society such as recreation and tourism.

b. Drugs, herbs, food and other important raw materials can be derived from plants and animals.
c. It also preserves the genetic diversity of plants and animals.

d. Ensures the sustainable utilization life supporting systems on earth.

 Quest. Give few examples for endangered and endemic species of India.

 Endangered species

1. Reptiles : Tortoise, python

2. Mammals : Indian wolf, Red fox, Tiger

3. Primates : Hoolock gibbon, Golden monkey

4. Plants : Rauvol serpentina, Santalum

Endemic Species
1. Flora: Sapria Himalayan, Ovaria lurida

2. Fauna: Monitor lizards, Indian salamander.

 Quest. Explain threatened and endangered species.  

A species is said to endangered, when its number has been reduced to a critical level. Unless it is protected and conserved, it is in immediate danger of extinction.

 Quest. What do you understand by the term flora and fauna? 

Flora: Plants present in a particular region or period.
Fauna: Animals present in a particular region or period.

 Quest. Explain vulnerable species.

A species is said to be vulnerable when its population is facing continuous decline due to habitat destruction or over exploitation. Such a species is still abundant.

 Quest. What is in-situ conservation?

In-situ conservation involves protection of fauna and flora within its natural habitat, where the species normally occurs is called in-situ conservation.

Quest. What is ex-situ conservation?

ANSWER: Ex-situ conservation involves protection of fauna and flora outside the natural habitats.

 Quest. What are the advantages and disadvantages of ex-situ conservation?

Advantages:

a. Survival of endangered species is increasing due to special care and attention.

b. In captive breeding, animals are assured food, water, shelter and also security and hence longer life span.
c. It is carried out in cases of endangered species, which do not have any chances of survival, in the wild.
Disadvantages:

a. It is expensive method

b. The freedom of wildlife is lost

c. The animals cannot survive in natural environment.

Quest. Enumerate the human activities which destroy the biodiversity.  

a. The farmers prefer hybrid seeds, as a result many plant species become extinct.

b. For the production of drugs the pharmaceutical companies collect wild plants, so several medicinal plants now become extinct.
c. Tropical forest is the main sources of world‟s medicine. Every year these forests are disappearing due to agriculture, mining and logging.

ENVIRONMENTAL POLLUTION

Quest. Define pollution.

Pollution is generally defined as the addition of the constituents to water, air or land which adversely alter the natural quality of environment.

Quest. Name any four air pollutants and their sources and effects.

Name of the Pollutant: Carbon monoxide
Sources: Cigarette smoking, incomplete burning of fossil fuels
Effects: Coma, brain cell damage

Name of the Pollutant: Nitrogen dioxide
Sources: burning of fossil fuels
Effects: Acid rain, lung damage

Name of the Pollutant: Sulphur
Sources: Coal burning
Effects: Breathing problem, acid rain

Name of the Pollutant: Lead
Sources: Paint, smelter, leaded petrol
Effects: Mental retardations, harm to wild life

Quest. Give examples for primary and secondary air pollutants.

Primary pollutants are those emitted directly in the atmosphere in harmful form.

Example: CO, NO, SO2 etc

Some of the primary pollutants may react with one another or with the basic components of air to form new pollutants. They are called as secondary pollutants.

Quest. Classify air pollutants with suitable examples. 

1. Primary pollutants: (CO, NO, SO2)
2. Secondary pollutants:(HNO3, H2SO4)

Quest. What are the causes of air pollution?  

(i) Incomplete burning of fossil fuels, liberate CO, NO2, etc.
(ii) Coal burning in power plants, liberate SO2
(iii) Paint, smelters, lead manufacture, liberate Pb.
(iv) Agriculture, decay of plants, liberate hydrocarbons

Quest. Define photochemical smog.

The brownish smoke like appearance that frequently forms on clear, sunny days over large Cities with significant amounts of automobile traffic. It is mainly due to chemical reactions among nitrogen oxides and hydrocarbon by sunlight.

Quest. What are point and non-point sources of water pollution?

Point sources are discharged pollutants at specific location through pipes, ditches or sewers into bodies of surface water.
Non-point sources: They cannot be traced at any single site of discharge. They are usually large land areas or air sheds that pollute water by runoff, subsurface flow or deposition from the atmosphere.

Quest. Write any four major water pollutants.  

a. Pesticides and biocides

b. Heavy metals, mercury, crude oil, plastics

c. Industrial and agricultural wastes

d. Thermal pollution

Quest. What is meant by BOD and COD?  

BOD is the amount of oxygen required for the biological decomposition of organic matter present in the water.
COD is the amount of oxygen required for chemical oxidation of organic matter using some oxidizing agent like K2Cr2O7 and KMnO4

Quest. Define soil pollution.

ANSWER: The contamination of soil by human and natural activities which may cause harmful effects on living beings.

Quest. Write any two causes of soil pollution.

ANSWER: Industrial wastes, urban wastes, agricultural practices, radioactive pollutants, Biological agents.

Quest. What is marine pollution? 

The discharge of waste substances into the sea resulting in harm to living resources, hazards to human health, hindrance to fishery and impairment of quality for use of sea water.

Quest. Name the sources and effects of marine pollution. 

1. Sources: Dumping the wastes
Effects: Marine birds ingest plastic which causes gastrointestinal disorders.

2. Sources: Oil
Effects: Damage to marine fauna and flora, retard the rate of O2 uptake by water

Quest. Define noise pollution.  

Noise pollution is defined as the unwanted, unpleasant or disagreeable sound that causes discomfort for all living beings.

Quest. When a sound causes noise pollution?  

ANSWER: Noise beyond 120 dB causes noise pollution.

Quest. When does a sound causes noise pollution? 

The sound intensity is measured in decibel (dB), which is tenth part of the longest unit Bel. One dB is equal to the faintest sound, a human ear can hear. If the intensity of the sound exceeds 1 dB, noise pollution occurs.

Quest. Give any four methods to control noise pollution. 

a. Source Control
This may include source modification such as acoustic treatment to machine surface, design changes, limiting the operational timings and so on.
b. Transmission Path Intervention
This may include containing the source inside a sound insulating enclosure, construction of a noise barrier or provision of sound absorbing materials along the path.
c. Receptor control
This includes protection of the receiver by altering the work schedule or provision of personal protection devices such as ear plugs for operating noisy machinery. The measure may include dissipation and deflection methods.
d. Oiling

Proper oiling will reduce the noise from the machines.

Quest. Define thermal pollution.  

Thermal pollution is defined s the addition of excess of undesirable heat to water that makes it harmful to man, animal or aquatic life or otherwise causes significant departures from the normal activities of aquatic communities in water.

Quest. Name some important natural sources for nuclear hazards.

(a) The important natural source is space, which emit cosmic rays.

(b) Soil, rocks, air, water, food, radioactive radan-222 etc., also contain one or more radioactive substances.

Quest. Define hazardous wastes. 

Wastes like toxic chemicals, radioactive or biological substances which contribute to an increase in mortality or in serious irreversible illness to human health and environment are called hazardous wastes.

Quest. Why nuclear hazards are so dangerous?  

Radioactive radiation, liberated by nuclear hazards, affects the cells in the body and the function of glands and organs. People suffer from blood cancer and bone cancer if exposed to doses around 100 to 1000 roentgens. Unlike the other pollution, radioactive pollution can cause genetic disorders even in the subsequent generations.

Quest. How nuclear hazards can be disposed safely?  

ANSWER: Nuclear hazards are disposed safely by dumping them in a big concrete tank and throwing it in deep sea.

Quest. Mention some important control measures of nuclear hazards.

a. Nuclear devices should never be exploded in air. If these activities are extremely necessary then they should be exploded underground.
b. In nuclear reactors. Closed-cycle coolant system with gaseous coolants may be used to prevent extraneous activation products.
c. Containments may also be employed to decrease the radioactive emissions. It can be achieved by using tightly sealed boxes and closed cycle system.
d. Production of radioisotopes should be minimized, as once produced they cannot be rendered harmless by any means except the passage of time.
e. Minimum number of nuclear installations should be commissioned.

Quest. What are the various sources of radioactive pollution?  

1. Natural sources.
(a) The very important natural source is space, which emit cosmic rays.
(b) Soil, rocks, air, water, food, radioactive radon-222 etc. also contain one or more radioactive substances.
2. Man-made sources
Man-made sources are nuclear power plants, X-rays, nuclear accidents, nuclear bombs, diagnostic kits, etc., where radioactive substances are used.

Quest. Define solid waste?

Any garbage, refuse sludge from waste treatment plant, and other discarder material including solid, liquid, semi-solid from commercial, mining and agricultural operations are called as solid wastes.

Quest. What are the types of solid wastes?  

a. Municipal wastes
b. Industrial wastes
c. Hazardous wastes

Quest. Mention the sources of solid wastes.  

1. Domestic wastes – cloth, waste papers

2. Commercial wastes – cans, bottle, polythene bags

3. Construction wastes – Wood, Concrete

4. Biomedical wastes – Infectious wastes

5. Industrial wastes – Nuclear and thermal power plants

6. Hazardous wastes – Toxic wastes, chronic toxicity

Quest. Differentiate between recycling and reuse?

Reuse:
a. The refillable containers, which discarded after use can be reused
b. Rubber rings can be made from the discarded cycle tubes, which reduces the waste generation during manufacturing of rubber bands.
Recycling:
Recycling is the reprocessing of the discarded materials into new useful products
Example
a. Old aluminum cans and glass bottles are melted and recast into new cans and bottles
b. Preparation of cellulose insulation from paper.

Quest. What are the roles of women in environmental pollution?

a. In rural areas women plant trees and grass, grow vegetables with the drip-irrigation method on order to save water.
b. In urban areas they go shopping using cloth bags to reduce white pollution.

Quest. State the role and responsibility of an individual in the prevention of pollution.

a. Plant more trees
b. Help more in pollution prevention than pollution control
c. Use water, energy and other resources efficiently
d. Purchase, recyclable and recycled and environmentally safe products
e. Use CFC free refrigerators
f. Use natural gas than coal
g. Reduce deforestation.

Quest. What do you understand by soil pollution?  

The pollution affects and alter the chemical and biological properties of soil.
As a result, hazardous chemical can enter into human food chain from the soil or water disturbs the biochemical process and finally lead to serious effects on living organism.

Quest. What are causes of noise pollution?  

1. By machine like mechanical saws and pneumatic drill.
2. from transport, rail, air craft, road vehicles like , scooters, cars, motorcycles,buses.
3. common noise makers are musical instruments, TV, VCR, radios, transistors, Telephone and loudspeakers.

Quest. What are the effects of thermal pollution?  

1. Reduction in dissolved oxygen.

2. Increase in toxicity.

3. Interference with biological activity.

4. Interference with reproduction.

5. Direct mortality.

6. food storage for fish.

Quest. What are oxygen demanding wastes? 

Oxygen demanding wastes is the one to reduce amount of oxygen water in water is known as oxygen demanding wastes. The oxygen demanding wastes are BOD and COD
BOD is the amount of oxygen required for the biological decomposition of organic matter present in the water.
COD is the amount of oxygen required for chemical oxidation of organic matter using some oxidizing agent like K2Cr2O7 and KMnO4

Quest. What is cyclone?  

Cyclone is a meterological phenomena, intense depressions forming over the open oceans and moving towards the land. On reaching the shores, it moves intothe interior of the land or along the shore lines.

Quest. Mention the effects of ozone on plants.  

1. Ozone damages vegetation and ecosystems by inhibiting the ability of plants to open the microscopic pores on their leaves to breathe.
2. It interferes the photosynthesis process by reducing the amount of carbon dioxide the plants can process and release as oxygen.

Quest. What is acid rain (or) What is acid precipitation?

The presence of excessive acids in rain water is known as acid rain. It includes acid rain, acid fog, acid snow and other form of precipitation that is more acidic than normal. The presence of SO2 and NO2 gases in the atmosphere, decreases the pH of the water during the rainfall. This type of precipitation of water is called acid deposition.

Quest. Mention the causes and effects of acid rain. 

The gases nitrous oxide, sulphur dioxide due to burning of coal and oil, in the atmosphere react with water to form acids.

1. Acid rain corrodes houses, monuments, statues, bridges and fences.
2. Acid rain and dry deposition of acidic particles contribute to the corrosion of metals, and the deterioration of paint and stone.
3. Dry deposition of acidic compounds can also dirty buildings and other structures, leading to increased maintenance costs.

Quest. How does ozone layer depletion take place? Write its consequences.

Consequences

• Damage genetic materials in the skin cells, which cause skin cancer.
• Affect the aquatic forms (fish)
• Global warming.
• Degradation of paints, plastics, etc.

Quest. What are the causes and effects of ozone layer depletion?

Causes
Presence of:

(i) Chloro Fluoro Carbon.
(ii) Hydro Chloro Fluro Carbon (HCFC)

(iii) Bromo Fluoro Carbons (BFC)

Effect

(i) UV rays destroy the melamine pigment in human skin.
(ii) It also affects the aquatic forms.
(iii) It degrades paints, plastics and other polymeric materials.
(iv) Increases the average temperature of the earth.

Quest. “Ozone is a life savior, if present in stratosphere, but is a pollutant, if present in troposphere” Justify the statement.  

In stratosphere, ozone filters out the UV- radiation and protects us from the Damaging UV radiation of the sun.
But, in troposphere, it is highly reactive irritating gas with an unpleasant odor. It also Oxidizes atmospheric S, N and C as SO2, SO3, NO, NO2, CO, CO2 and cause pollution. It is also a major component of photochemical smog.

Quest. How CFC’s are accumulated in atmosphere.

CFC’s are accumulated in atmosphere through
(i) Aerosol propellants.
(ii) Cleaning solvents.
(iii) Refrigerants (Freon).
(iv) Foam plastic blowing agent.

Quest. Write the note of CFC.

CFC (Chlorofluoro carbon) is a green house gas (or) ozone depleting substance.
It was found that the ozone layer was attacked by chlorofluorocarbons (CFCs) which are released into atmosphere by refrigeration units, air conditioning systems, aerosol sprays and cleaning solvents. Chlorofluoro carbons release chlorine which breaks ozone into oxygen.Each chlorine atom is capable of attacking several ozone molecules. So that a long chain process is involved. A 1% loss of ozone results in a 2% increase in UV rays reaching the earth’s surface.

Quest. What is a Dobson unit?  

The amount of atmospheric ozone is measured by “Dobson spectrometer” and is Expressed in Dobson units (DU). 1 DU is equivalent to a 0.01 mm thickness of pure ozone at the density it possesses if it is brought to the ground level (1 atm) pressure. In temperate latitude its concentration is 350 DU.
In tropics its concentration is 250 DU.
In sub polar region its concentration is 450 DU.

Source: | NCERT |

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