MAN AND HIS ENVIRONMENT
Q. Define environmental Biology.
ENVIRONMENTAL BIOLOGY
The
scientific study of environment, ecology, evolution and global change within a
combined form is called environmental Biology.
Q. Describe the level
of organization.
LEVEL OF ORGANIZATION
The levels of organization in living world are
based on chemical foundation. All the living organisms are made up of cells and
the protoplasm of cell is physical as well as chemical basis of life. These
levels are as follows:
·
Atomic level of organization:
All the matter is made up of
elements and element is composed of atom. Atom is made up of sub atomic
particles called electron, proton and neutron.
There are 16 bio-elements which
are essential for life among which six are basic including C, H, O, N, S and P.
·
Molecular level of organization
Molecules are formed by the
binding of atoms. Molecules are classified into micro-molecules like glucose,
amino acids and fatty acids whereas macromolecules are carbohydrates, proteins
and lipids.
·
Cellular level of organization
The biomolecules when work
together in the form of suspension, it is called Protoplasm. When protoplasm
works in the form of a unit, this is called Cell. Cell is the basic unit of
living organisms. When similar type of cell organizes together in a group, they
are called tissues. The different types of tissues arranged in a particular
manner to work together are called Organs. Organs of different types work in a
coordinated manner to perform a function are called Organ-system. When
different organ-system functions in co-ordination in as a unit, they form a
body or Multicellular Organism.
·
Taxonomic level of organization
The Species is the smallest unit
of taxonomic level of organization, which can be defined as the organisms which
are reproductively isolated from other groups.
·
Population level
All the members of a species,
living in specific habitat are called Population. A group of parrots living on
tree is called parrot population.
·
Community level of organization
The members of different species
living in specific habitat are called as Community. A group of different kind
of birds, living on tree, is called as bird community.
·
Ecological system
Communities always depend upon
their non-living environment in a reciprocal interaction for their survival.
For example oxygen for respiration is obtained from environment and in turn
given out CO2.
·
Biosphere level
The part of earth where life
exists is called biosphere. It consists of different kinds of eco systems.
Q. Define biotic components. Also give few
examples.
BIOTIC COMPONENETS
The
living organisms which interact in an ecosystem are called Biotic components.
The
living components include:
·
Producers
·
Consumers
·
Decomposers
Q. Which one is the first trophic level of
ecosystem and how?
PRODUCERS
Producers
are the first trophic level of ecosystem as because they prepare their food
themselves they are placed on first trophic level.
Organisms
which prepare their food (glucose) for themselves and for others are called
producers.
They
are primary source of energy for other organisms.
Example
of producers includes; photosynthetic bacteria, algae, plants etc.
Q. What do you know about Consumers? Also
describe its types.
CONSUMERS
Organisms
that cannot prepare their own food and depend on producers for their food
content are called consumers.
On
the basis of feeding level, consumers are of three types:
·
Primary
consumers
·
Secondary
consumers
·
Tertiary
consumers
· Primary consumers
Consumers which directly feed on producers are called
primary consumers.
For instance; grasshopper or caterpillar feed leaves of the
plants.
They are commonly known as herbivores.
·
Secondary consumers
Consumers which feed on primary consumers are called
secondary consumers.
For instance; bird eats grasshopper.
They are commonly known as carnivores.
·
Tertiary consumers
Organisms which feed on secondary consumers are called
tertiary consumers.
For instance; eagle eat small birds.
They are commonly known as carnivores.
Summary
Leaves
→ Grasshopper → Sparrow
→ Eagle
(Producers) Primary
consumer Secondary
consumer Tertiary consumer
Q. Define Decomposers.
DECOMPOSERS
Organisms
which eat dead organic substances are called decomposers.
Decomposers
are mostly bacteria, fungi etc.
Q. What is meant by Abiotic Component of Ecosystem?
Name some important abiotic components.
ABIOTIC COMPONENTS OF ECOYSTEM
Abiotic
components are the physical aspects of its surrounding which influence upon the
biotic component.
The
most important abiotic components are:
·
Light
·
Temperature
·
Water
·
Soil
·
Air
Q. What is the effect of light on ecosystem?
LIGHT
Light
is the most important factor. Plant converts light energy into chemical energy
by the process of photosynthesis. Only a small amount of light is converted
into chemical energy by the plants but a large amount is responsible to
maintain the temperature of earth and atmosphere.
Light
also has importance on animals like without light animals cannot see, certain
chemical process require light like synthesis of Vit. D.
Q. What is the effect of temperature on
ecosystem?
TEMPERATURE
Temperature
is another most important abiotic component. At high altitudes, it is low and
high at low altitudes.
Temperature
varies from season to season.
Enzyme
activity has great influence on temperature. Minor fluctuations in the
temperature can lead to inactivity of enzyme.
Q. What is the effect of water on ecosystem?
WATER
Water
constitutes 3/4th part of the universe.
In
cell, water constitutes the 70% part of the protoplasm.
The
amount of water gets balanced on the earth by water cycle in which rainfall and
snowfall plays a key role. Similarly, the amount of water plays a key role in
vegetation. It means, water controls the distribution of plants and animals on
land.
Q. What is the effect of soil on ecosystem?
SOIL
Soil
is the upper layer of earth’s crust which contains minerals and decomposed
organic matter. The remains of dead organic substances are called humus.
Humus
enriches the soil and increases its water and sir holding capability.
The
type of soil and its fertility determines the flora and fauna of an ecosystem.
Q. What is the effect of air on ecosystem?
AIR
Air
plays an important role in ecosystem. Mainly, air consists of 78% Nitrogen, 21%
Oxygen, 0.04% Carbon dioxide and other gases.
·
Nitrogen
is essential for protein.
·
Oxygen
is essential for respiration
·
Carbon
dioxide is essential for photosynthesis.
Q. What is mean by Trophic level and food
chain?
TROPHIC LEVEL
The
step of transfer of energy rich food is called trophic level.
FOOD CHAIN
The
series of transfer of energy from one trophic level to other is called food
chain.
Q. How does the energy flow in an ecosystem as
a non cyclic process?
Producers
absorb the sunlight and convert this solar energy to chemical energy by
undergoing the process of Photosynthesis. A small part of this energy is
transfer to primary consumers when they eat them. Similarly, a small part of
energy is transferred from primary to secondary and secondary to tertiary
consumers when they eat them. This is how the transfer of energy takes place.
But only a small amount of energy is transfer from one trophic level to another
because major part of energy gets lost in the form of heat.
Q. Write a brief note on food chain and food
web.
FOOD CHAIN
food
chain occurs rarely as it is single way chain which is associated with the
transfer of energy from one trophic level to another.
For
instance,
In
grassland ecosystem, the grass is eaten by grasshopper, locust and rabbits etc.
these in turn eaten by sparrows, lizards and jackals respectively.
Aforementioned organisms; sometime eaten by hawks and tigers etc.
FOOD WEB
Food
web is the association of linkage of various food chains.
For
instance; an organism derives its food from more than one source. Such
organisms are eaten by several organisms.
Q. What is mean by ecological pyramid?
ECOLOGICAL PYRAMID
A
graphical representation designed to show the biomass or bio-productivity at
each trophic level in a given ecosystem is called Ecological Pyramid.
OR
Presentation
of number of individuals or amount of biomass or energy in various trophic
levels from lower to higher level is called ecological pyramid.
Q. Who is Charles Elton? What is his
contribution in ecological system?
Charles
Elton is an English ecologist who developed the concept of ecological pyramids
in 1927.
According
to him, the number of organisms in an ecosystem decrease gradually at each
higher trophic level.
Q. What is mean by pyramid of mass and pyramid
of numbers?
PYRAMID OF NUMBERS
Graphic
presentation of members of population in an area at different trophic levels is
called pyramid of numbers.
For
instance; number of organisms decreases in each higher trophic level.
PYRAMID OF BIOMASS
Graphic
representation of total biomass in an area at different trophic levels is
called pyramid of Biomass.
For
instance;
Each
higher feeding level contains less biomass than the previous trophic level. It
results due to expenditure of energy in each level.
Q. What is mean by biogeochemical cycle?
BIOGEOCHEMICAL CYCLE
The
repetition of elements’ cycle from organism to environment and environment to
organism is called biogeochemical cycle.
For
instance;
The
growth and life processes of living organisms require various elements. These
elements are taken up from environment by producers then it is transferred from
producers to consumers, consumers to decomposers and from each organism to back
to the environment.
Q. What are the characteristics of
biogeochemical cycles?
CHARACTERISTICS OF
BIOGEOCHEMICAL CYCLES
A
biogeochemical cycle has the following characteristics.
·
Movement
of nutrients from environment to organism and vice versa.
·
Involvement
of biological processes.
·
A
geochemical reservoir
·
Chemical
changes
Q. Describe carbon oxygen cycle.
CARBON OXYGEN CYCLE
Carbon
has a great role on life activities. Like it is needed for formation of
proteins, carbohydrates, fats and many other organic substances.
Carbon
is present in the carbon dioxide. Phototrophic organisms absorb this carbon
dioxide gas in order to undergo the process of photosynthesis. By the
photosynthesis, plant prepares glucose. Carbon, in the form of glucose enters
into the food web.
The
amount of carbon dioxide gets balanced in the air, as animals excrete carbon
dioxide along with the activity of decomposers which set CO2 free
from dead organic substances.
Also
the process of burning of wood, petrol, coal and gas results in the release of
CO2 gas.
Q. Which two important processes run the
carbon-oxygen cycle?
Photosynthesis
and respiration helps a lot to run carbon-oxygen cycle.
·
Photosynthesis:
it consumes CO2 and release O2 gas
·
Respiration:
It consumes O2 gas and release CO2 gas
Q. Describe nitrogen cycle.
NITROGEN CYCLE
Nitrogen
is one of the most important constituent of protein and DNA. plants use
atmospheric nitrogen in the form of nitrates.
The
nitrogen cycle consists of three phases.
·
Nitrogen
fixation
·
Nitrification
·
Denitrification
Q. What do we mean by nitrogen fixation and how
it occurs in an ecosystem?
NITROGEN FIXATION
Nitrogen
fixation means to convert atmospheric nitrogen gas into nitrates.
Nitrogen
fixation can be done by two processes:
1. During lightening,
atmospheric nitrogen combines with oxygen to form nitrates. By the help of
rain, nitrates reach the soil.
2. Nitrogen fixing
bacteria: nitrogen fixation can be done by following three types of bacteria,
which are called nitrogen fixing bacteria.
o
Water
living bacteria [Cyanobacteria]
o
Soil
living bacteria
o
Roots
living bacteria
Q. What do we mean by nitrification?
NITRIFICATION
The
process by which nitrogenous compounds of living organisms convert into
nitrates is called nitrification.
Nitrification
is usually performed by soil living microorganisms.
These
nitrates are absorbed by the plant so the nitrogen cycle begins.
Q. What do we mean by denitrification?
DENITRIFICATION
The
process of conversion of nitrogenous compounds into free nitrogen is called
Denitrification.
Denitrification
is done by denitrifying bacteria which breaks the ammonia or nitrates into free
nitrogen. This free nitrogen returns to the air to complete the cycle.
Q. What is mean by nitrogenous wastes/
nitrogenous compounds?
NITROGENOUS WASTES/
NITROGENOUS COMPOUNDS
Proteins
of dead plants and animals, excretory waste like ammonia, urea, uric acid are
called nitrogenous waste/ nitrogenous compounds.
INTERACTION IN THE ECOSYSTEM
Q. What is mean by competition?
COMPETITION
competition
is actually a cold war between the organisms of a community occupying the same
habitat.
Competition
may be interspecific or intraspecific.
· Inter-specific competition
Competition
between the members of different species is called interspecific competition.
· Intra-specific competition
Completion
between the members of same species is called intracompetition.
Q. What is mean by Predation?
PREDATION
A
predator is an organism which captures and kills the alive animals for its
food.
Predator
may be primary, secondary or tertiary consumers.
Predator
relationship is an important factor in which one population determines the
population of other predator-prey relationship.
Q. What is mean by Symbiosis?
SYMBIOSIS
Association
of organism in which two organisms of similar species live together is called
symbiosis.
On
the basis of benefit or harm, symbiosis may be of three types.
·
Commensalism
·
Mutualism
·
Parasitism
Commensalism
It
is a type of symbiotic relationship in which one of the organisms gets benefit
whereas the other organism is neither benefited nor harmed.
For
instance;
Spirochaetes,
[A
kind of bacteria that resides in the human teeth, which causes neither benefit
nor harm to us]
Mutualism
The
association of two different type of organisms in which both the partners gets
equal benefit from each other is called mutualism.
For
instance;
Nitrogen
fixing bacteria
[Rhizobium
bacteria get the food from roots of leguminous plants and convert gaseous
nitrogen into nitrates which is required for plant growth].
Parasitism
It
is a type of symbiotic relationship in which one organism gets benefit from
other by causing harm to that organism.
Parasites
may be of two types;
·
Ectoparasite
[Parasite that reside outside the host body]
·
Endoparasite
[Parasite that reside inside the host body]
ECOSYSTEM
BALANCE AND HUMAN DIET
Q. How is the man exploiting the ecosystem?
Men
for his comfort exploiting natural resources adversely. Although his scientific
inventions provides him many comforts of
life but he’s entitling himself for various ecological disturbances which
includes, desertification of land due to erosion and deforestation, flooding,
accumulation of waste and toxic substances, pesticide contamination,
radio-isotopes accumulation, depletion of natural resources, spread of diseases
and infection etc.
Q. What is mean by Ps?
Ps
means Population, Pollution and Poverty.
Q. What did Dr. Paul Ehlrich of Standford
University say about Population Explosion?
Dr.
Paul Ehlrich extends the term ‘Population Explosion’ to ‘Population Bomb’. He
states that Population bomb is more dangerous and catastrophic than atom bomb.
Q. Write a short note on Urbanization?
URBANIZATION
Urbanization
is defined as the rapid increase in the population.
This
occurs due to the migration of people from rural areas to the urban areas for
the cause of jobs, education and better standard of lives.
These
rapid increase in population causing pollution, drug abuses, kidnapping,
dacoities, religious conflicts, ethnic clashes, linguistic riots etc.
Surprisingly,
if we don’t control the birth rate and rapid growth, nature will forcefully
perform natural population controls by means of diseases, war etc.
Q. Write a short note on Greenhouse effect.
GREEN HOUSE EFFECT
A
natural process by which radiations from sun are absorbed by the green house
gases and into reflected back into space is called Green House effect.
The
green house gases are CO2 and methane that are produced from the
burning of fossil fuels. If high quantities of these gases are produced, they
accumulate below the ozone layer and do not allow heat energy of the sun to go
back in the space.
As
a result, the heat remains in the earth’s atmosphere and increases the
temperature. This is called global warming OR Greenhouse Effect.
Q. Write a short note on Acid Rain.
ACID RAIN
A
mixture of sulphur dioxide and nitrogen dioxide in the atmosphere that combines
with the falling water and forms sulphur acid and nitric acid respectively,
these acids remains as vapors and condenses when temperature falls, and falls
on the ground as acidic rain.
The
acid rain can destroy soil, microorganisms of soil, skin of animals, building
material etc.
Q. What is mean by deforestation?
DEFORESTATION
The
action of clearing wide areas of trees is called Deforestation.
Deforestation
is caused by various factors:
·
Fuel
·
Fodder
·
Timber
·
Agricultural
needs,
·
River
valley projects,
·
Industrial
purposes,
·
Conservation
of dams,
·
Construction
of roads,
·
Construction
of buildings etc.
Deforestation
may result:
·
Recurrent
floods,
·
Soil
erosion,
·
Lowering
of ground levels,
·
Declination
of annual rain fall,
·
Loss
of fertility of the soil,
·
Reduction
in wild life and
·
Greater
incidence of diseases.
Q. Define pollution. Name various pollutants.
POLLUTION
The
undesirable change in the physical, chemical or biological characteristics of
air, land, water and soil which may harm the living activities as well as non
living activities is called pollution.
Generally pollution is classified as:
·
Material
pollution
·
Non
material pollution
Material
pollution
A
type of pollution where some materials or substances exceed their limits in the
environment is called material pollution.
For
instance;
·
Air
pollution
·
Water
pollution
·
Soil
pollution
Non
material pollution
A
type of pollution where material does not increase but environment disturb or
become unbearable to live is called non material pollution.
For
instance;
·
Noise
pollution
·
Heat
or radiation pollution
Q. Name some common pollutants.
·
Deposited
materials like Soot, smoke, tar, dust and grit
·
Gases
like SO2, CO, CO2, NO2, Cl2, O3
etc.
·
Chemical
compounds like aldehyde, arsines, HF, CFC etc.
·
Heavy
metals like lead, mercury, iron, zinc etc.
·
Economic
poison like herbicide, fungicide, insecticide etc.
·
Fertilizers
·
Radioactive
substances
·
Noise
and heat
Q. Write note on Air Pollution.
AIR POLLUTION
The
increased amount of solid waste or concentration of gases in the air is called
air pollution.
Causes
·
Automobiles,
·
Electric
power plant,
·
Industrial
processes,
·
Heating
and cooking,
·
Transport.
Effects
·
Acid
rain,
·
Greenhouse
effect,
·
Ozone
depletion
Control
Air
pollution can be controlled by:
·
Use
of proper filters: industrial pollutants must be passed through filters. So the
particulate matter is removed.
·
Use
of solar cooker: industries should use solar cooker or bio gas producing units.
·
Environment
friendly fuels: use lead free fuels, sulphur free fuels, uses of CNG gases.
·
Afforestation:
Development of new forests.
Q. Write a short note on Depletion of Ozone
layer.
DEPLETION OF OZONE LAYER
The
gradual thinning of ozone layer is called depletion of ozone layer.
Ozone
layer is much important for living organisms as it protects the ultraviolet
radiations from sun which are lethal for living organisms.
Depletion
of ozone layer is mainly associated with the CFC (Chloro-Floro Carbon), as CFC
reacts with ozone and converts it into oxygen gas.
Q. What is water pollution? What measure can be
taken to control water pollution?
OR
Write note on water pollution.
WATER POLLUTION
The
contamination in water is known as water pollution which is mainly caused by
human activity.
The
water pollution affects the aquatic organisms and quantity of water which
directly or indirectly affect the life of human beings.
Sources of water pollution
·
Organic pollutants: Domestic
sewage, agriculture run off, organic waste from breweries, bacteria, milk
dairies, sugar mills, hotels etc.
·
Chemical pollutants: Pesticides,
insecticides, fungicides, herbicides, detergents, heavy metals, acid, mine
waste, oil, radioactive material etc.
·
Thermal pollutants: Effluents
from electric power plants or nuclear reactor plants.
·
Siltation: deposition of soil and
sand in the bottom of water reservoirs which raise the water levels and
decrease water holding capacity.
Control of
water pollution
·
Public
awareness
·
Strict
legislation and implantation is required on sewage treatment and industrial
recycling processes.
·
No
industrial and agricultural waste should be added to water bodies before
complete treatment.
Q. What do you know about Eutrophication?
OR What is algal bloom and how it destroys
the life of an ecosystem?
EUTROPHICATION
Growth
of algae with very high rate due to increase in Phosphorous and nitrogen
containing compounds is called algal bloom or eutrophication.
Causes
·
Algal
bloom when floats on water surface spoil fishing, swimming and recreational
qualities of water.
·
After
dying, these algal species add more organic matter in water and/ or toxins that
cause lethal effects to the living organisms.
Q. What causes the inability of light to reach
the deep water layers?
The
excessive growth of decomposers uses the excessive oxygen of water which leads
to the death of the other organisms.
This
excessive growth and died organisms reduces to the lower layer in water.
Q. Write note on Soil Pollution.
SOIL POLLUTION
The
alteration in the natural soil environment is called soil pollution.
Causes of soil pollution
·
Mining
·
Excavation
of soil for bricks,
·
Cement
making,
·
Construction
of roads, buildings etc.
·
Dumping
of solid wastes.
·
Deforestation
·
Over
grazing
·
Excessive
use of fertilizers
·
Poor
drainage system
Control of Soil Pollution
·
Recycling
of solid wastes,
·
Proper
dumping of solid wastes,
·
Plantation,
·
Afforestation,
·
Proper
irrigation system.
Q. What is mean by conservation?
CONSERVATION
Conservation
is a plan of avoiding unnecessary use of natural materials or resources or a
careful preservation and protection of natural resources by proper management
to prevent exploitation, negligence, destruction etc.
Q. Name some endangered mammals of Pakistan.
·
Punjab
Urial
·
Markhor
·
Snow
leopard
·
Asia
sandspit green turtle
·
Indus
river Dolphin
·
Bear
of Deosai
Q. Name some endangered birds of Pakistan.
·
Siberian
crane
·
Falcon
·
Cheer
pheasant
·
Chacor
·
Long
billed vulture
·
Red
Avadavar
Q. What has government planned so far for the
conservation of nature in Pakistan?
Government
of Pakistan has developed different plans.
·
National
parks = 29
·
Wild
life sanctuaries = 69
·
Game
reserves = 26
·
Protected
wetlands = 19
·
Protected
and reserved forest = 07
·
Marine
protected areas
·
Pakistan
national biodiversity strategy and action plan 2015
·
Biodiversity
action plan by IUCN/ WWF/ World Bank, 1999.
·
National
conservation strategy plan, 1993.
·
Wild
life conservation project in Pakistan, 2007.
·
Sustainable
Forest Management UNDP in Pakistan. Project 2016-2020
·
Himaalyan
Jungle Project (HJP), 1991-1994.
·
Palas
conservation and Development Porject (PCDP), 1994
·
Indus
Dolphin Project (IDP), 1977.
·
Marine
Turtle Conservation Project, 1980.
·
Kirthar
national Park, Sindh
·
Toghar
Conservation Project (TCP), Balochistan, 1985
·
Conservation
of Chilghoza Forest and Associated Biodiversity of Suleiman Range, Balochistan,
1992.
·
Maintaining
Biodiversity with Rural Community Development, 1999.
·
Northern
area Conservation Project (NACP), 2000.
·
Conservation
of snow leopard in Northern Pakistan.
·
Conservation
of Migratory Birds in Chitral, NWFP (KPK), 1992
·
Himaalyan
Wild Life Project (HWP), 1993.
·
Conservation
of Chiltan Markhor in Hazarganji Chiltan national park, Quetta.
·
Protected
areas Management Project.
·
Bear
Baiting in Pakistan
Q. Which institutions in Pakistan work for
conservation?
·
Environment
and climate change (UNDP) in Pakistan
·
Society
for conservation and protection environment, SCOPE
·
Environment
and natural resource management (National Rural Support Program)
·
Conservation
in Pakistan
·
National
energy efficiency & Conservation authority
·
Environmental
organization in Pakistan (Help save Pakistan’s environment)
·
Pakistan
environmental protection and resource conservation project.
·
Pakistan
environmental protection agency (PEPA)
·
Himaalyan
Wild Life Foundation (HWF)
