ENVIRONMENTAL SCIENCE

ENERGY FLOW• Movement of energy through ecosystems• Foundation of life (Sustains the life)• Limits the abundance and richness of life• ECOSYSTEM ENERGY• Sun(outside source)- the ultimate source of energy• Ecosystem energy do not circulate• Energy flow is a one way path• Energy is utilized and converted to heat (demand for

food)• Continues flow of energy is required to keep the

biological process active

• Energy entering pathways are 2.– By the primary producers(Auto trophs)

– By the wind current or air convection through soil

ENERGY FLOW

FOOD CHAIN• One way of representing Energy flow• Transfer of food from plants(producers) through

herbivores-carnivores-decomposers• Above process repeats in stages• The simple stages of eating and being eaten is the

FOOD CHAIN– 1. Grass-deer-lion– 2. seed-mouse-owl

FOOD CHAIN• Types – Grazing food chain– Detritus food chain

FOOD CHAIN

FOOD CHAIN• Grazing food chain depends on solar energy• Detritus food chain do not depends on solar energy• TOPHIC LEVEL• Feeding status of an ecosysytems• Organisms feed on plants belongs to same steps or

trophic level• Number of trophic levels depend on the population of

species and distribution of foodEg: Wheat->Man

: Algea->insects->fish->man

FOOD WEB• Series of interconnected food chains

terrestrial food web

FOOD WEB• Linear arrangements of food chain is difficult

ECOLOGICAL PYRAMIDS• Graphical representation of trophic structure of ES• Relationship b/w energy • 3 types– Pyramid of NUMBERS– Pyramid of BIOMASS– Pyramid of ENERGY

ECOLOGICAL PYRAMIDS• Pyramid of Number– Number of individual in a trophic level– The length of the bar represents the population– Progressive decrease in numbers from producers to

consumers

P

C1

C2

C3

ECOLOGICAL PYRAMIDS• Pyramid of Biomass– Based on the total dry weight of living material– Total number of population X av. Weight of pop.= Biomass

• Pyramid of Energy- Based on rate of energy flow- Takes upright form always- Energy will be lost in the Upper levels

ECOLOGICAL SUCCESSION• Process through which the ES tends to change over a

period of time• Causes of ecological succession– Initial causeClimatic causes: wind, fire, erosionBiotic causes: activities of living creatures– Ecesis causeMigration, competition, aggregation, – Stabilisation causesStabilisation of communityReason:climate

ECOLOGICAL SUCCESSION• Types of succession– Primary and secondary– Primary successionIt is the initial development of ecosystemCommunity occupies on an unoccupied siteEx: forest on a new hardened lava formForest on a retreating glacier

- Secondary successionRe-establishment of ecosystemIn this remnants of previous biological community, organic

matters of previous community

ECOLOGICAL SUCCESSION• Characteristics

It is unidirectional in natureModifies the physical envIt is predictableIt involves various developmental stages

AUTOTROPHIC SUCCN. HETROTROPHIC SUCCN.

Wide spread in nature Localized in nature

Starts in Inorganic env. Organic env.

Early dominance of Autotrophs Early dominance of Hetrotrophs(bacteria, fungai)

Energy flow is maintained indefinitely Energy flow is limited

MAJOR CYCLES IN ECOSYSTEM• WATER CYCLES• Rain water partly flows to river and partly get

infiltrated • Stored for an year• Water is taken by the plants• By Transpiration from leaves water escapes• Condensate and the precipitate• From the water body: Evaporation-condensation-

precipitation• This cycle continues

MAJOR CYCLES IN ECOSYSTEM• WATER CYCLES

MAJOR CYCLES IN ECOSYSTEM• CARBON CYCLE• Carbon included in ABIOTIC and BIOTIC parts• Building block• Plants takes CO2 + Light fixationcarbohydrates • Plants gives out O2• Hetrotrophs gives out CO2

• OXYGEN CYCLE• It is a part of Carbon cycle

MAJOR CYCLES IN ECOSYSTEM• CARBON CYCLE

• OXYGEN CYCLE

MAJOR CYCLES IN ECOSYSTEM• NITROGEN CYCLE• Plants take nitrogen from the soil• Waste material from the

animals get broken down by the bacteria• Ammonia get digested by the bacteria convert it into Nitrites • Nitrate fixing bacteria

convert Nitrate to Nitrites

MAJOR CYCLES IN ECOSYSTEM• NITROGEN CYCLE

CATEGORIES OF ECOSYSTEM • GRASSLAND ECOSYSTEM • Terrestrial ecosystem• Rainfall is low(250mm-600mm), soil is of poor quality • Major community is grass with few trees• Abundant grazing animal• Soil rich in humus• Occupies 90% of earth• FOOD CHAIN• GrassG. hopperhawk• Grassmousesnake

CATEGORIES OF ECOSYSTEM • GRASSLAND ECOSYSTEM

Structure and function of EcosystemsABIOTIC COMPONENTS BIOTIC COMPONETS

Nutrients in the soil includes C,H,N,O,P,S,Water CO2, Nitrates

PRODUCERS CONSUMERS DECOMPOSERS

Mainly grasses and few forbs and shrubs

Pri. ConsumersCow, rabits, sheeps

Secondary cosumersFox birds

Ter. Cosumershawk

Microbes like fungi, bacteria

CATEGORIES OF ECOSYSTEM • DESERT ECOSYSTEM • It occupies 17% of land area• Receives annual rainfall below 25cm• Large unoccupied area, poor availability of water• Evaporation rate is high• Less humidity• Continues sunshine temperature is about 380ᴼC day

time night 4ᴼC• Vegetation includes shrubs underground corns• Here the animals can conserve water and food for long

time

CATEGORIES OF ECOSYSTEM • DESERT ECOSYSTEM

ABIOTIC COMPONET BIOTIC

Dry soil with fewer rainfall and high temperature.

Lack of organic matter in soil

PRODUCERS CONSUMERS DECOMPOSERS

Shrubs , some grass and few trees

P. con.Insects camels

S. ConLizard beetle reptiles

T . Con.Red tailed hawk, vultures

Thermophilic fungaiBacteria

Poor vegetation decomposers are very low

CATEGORIES OF ECOSYSTEM • AQUATIC ECOSYSTEM ( FRESH WATER)• Pond lake ES• Artificial or nature, temporary or permentant• Self sufficient and self regulating• Stagnent• More polluted, due to

• limited amount of water• Over utilisation of species

CATEGORIES OF ECOSYSTEM • AQUATIC ECOSYSTEM ( FRESH WATER)

Abiotic component Biotic componets

Temperature, light, pH, water, organic and inorganic component

Producers Consumers Decomposers

Rooted plants, floating or suspended plants, phytoplanktons

p. con.Animal feeding microphytes, birds feeding phytoplankton

Sec. con.Insects, fishes, crabs

Ter. Con.Large fishes

Micro organisms like fungai, bacteria

BIODIVERSITY

What is Biodiversity• Definition• Verity of lives on earth• Include all life forms-fungai, protozoa, bacteria to plants,

birds fish and mammal• Variability in living organism from terrestrial marine and

aquatic ES and diversity within the speciesHierarchical levelsI. Genetic diversityII. Species diversityIII.Ecosystem diversity

What is Biodiversity• Genetic diversity• Variation of genes within the species• Genes : basic unit of all life• Genes are responsible of both similarities and difference b/w

organisms• Within a species there can be slight variations in size, shape,

resistance against diseases• To conserve genetic diversity , diff population must b conserved• Degree of conservation assessed from• Diversity within breeding pop.• Within species• Ability to withstand env. condition

Genetic diversity

What is Biodiversity• Species Diversity• Richness of species in an ecosystem• Counting the numbers and chances of species in an

ecosystem• Ex; A community in which each species of same

number of individual- more diverse• A community in which a particular species of large

number of individual- less diverse

What is Biodiversity• Ecosystem diversity• Existence of different ecosystem in a continent• It can be assessed in terms of species diversity• Assessment- evaluation of richness of species and their

relative abundance • Landscape diversity• Refer to size of several ecosystems • Refers to their interaction with the land surface

MEASURING B. D.• Alpha diversity• Refers to the number of species in a communityEx; Sahara desert and Amazon tropical rain forest• Beta diversity• Refer to degree to which a communityChanges along env. GradientEx; Moss community• Gamma diversity• Rate at which additionalSpecies are seen in ES due to Change in geographical condition

MODULE 1

The Multidisciplinary nature of Environmental Science

Introduction • World comprises two components:-

• Natural world —Plants, Animals, Soil, Air and water.• Anthropogenic world —Social institutions, mechanical devices

buildings created for ourselves (using sciences, technology and political organisations)

Definition of EnvironmentPhysical, biological, biophysical, topographical and climatological

conditions that surround and organisms or group of organisms

Environmental ScienceIs an applied interdisciplinary field concerned with the environment

around usIs concerned with social issues:- Environmental policies and law,

sustainability, resource economics, urban planning, environmental ethics

Introduction • Environmental science

Knowledge of ES need understanding in agriculture, anthropology, genetics…

Is a study of interaction among physical chemical biological components

Introduction • Goals of Evs Studies

Reduction of societal consumption of non-renewable fuel resources Development of alternate low carbon renewable energy resources Conservation of scarce material resources Protection of unique ecosystems Preservation of endangered species Establishment of Biosphere reserves

• ScopeCreate awareness among the people to know about renewable and non-renewable resources of regionProvide knowledge of ecological systems

Introduction • Goals

Reduction of societal consumption of non-renewable fuel resources Development of alternate low carbon renewable energy resources Conservation of scarce material resources Protection of unique ecosystems Preservation of endangered species Establishment of Biosphere reserves

• ScopeCreate awareness among the people to know about renewable and non-renewable resources of regionProvide knowledge of ecological systemsEnables to understand the cause and consequences of natural and man made disasters and pollution and measures to minimize itEnables environmentally literate citizen to make apt judgment and decision for the protection and improvement of earth

Introduction • Scope (continues)

Exposes the problems of over population, health, hygiene and role of art science and technologies to various environmental issues

Study convert theoretical knowledge to practice It teaches the citizen the need for sustainable utilization of resources

• Importance To study the env. In totality To understand the Economic value of the nature To understand the whole of the life process of man To understand the interdisciplinary approach of this branch To activate the participation of people in prevention and control of

various kinds of pollution To control the human beings in the use of food, apparels, plastics,

fuels, water, paper, electricity

Introduction • Importance (continues)

To understand the environmental issues from local, regional, national, international point of view

To enable the cooperation from regional national and international level on env. Issues

To understand the whole of the life process of man

To understand the Aesthetic and Recreational value of nature

To make the citizen to compete to do scientific work to find the practical sol. to current env problem

To motivate the people in planned usage of resources

NEED OF PUBLIC AWARENESS• Introduction

Enhanced pace of development activities and rapid urbanization-- resulted in stress on natural resources and quality of life

Trend of increasing pollution in various environmental media is evident from the deteriorating air and water quality, higher noise levels, increasing vehicular emission

Realizing the urgent need for arresting the trend, Ministry adopted Policy for Abatement of Environmental Degradation

Urgent need for public awareness about cleaner environment

Education should be given to women and children

NEED OF PUBLIC AWARENESS• How to create awareness…

By forming an Action group and recognised NGOs By joining local green movement and env. Conservation programmes By propagating 3R principles By organizing debates on env. Conservation with the help of

educational institution By arranging tours to National Parks, Santuaries

• Institutions on EnvironmentInstitution Duties

Bombay Natural History Society(1883)It disseminate knowledge of flora and fauna by means of lectures, field trips, literature

Center for Environmental Education(1984)

It aims to create env. Awareness amon the communities

NEED OF PUBLIC AWARENESS• Institutions on Environment

Institution Duties

Center for Science and Environment Researches in the field of pollution, forest, wildlife, land and water use

Indian Association of Environment Management(1963)

It conduct seminars, essay competition and exhibitions related to water pollution

NATURAL RESOURCES• Naturally occurring substances undisturbed by humans

• Activities associated with it:- extraction and purification

• Natural resources industries:- mining, petroleum extraction, fishing, hunting and forestry

• Classifications:- based on by – 1. source of origin, – 2. stage of development, – 3. renewability

NATURAL RESOURCES• Based on Origin:-

• Biotic Resources• Abiotic Resources

• Based on Stage of development– Potential Resources:- petroleum– Actual Resources:-wood– Reserved Resources:- profitably used– Stock resources:- hydrogen

• Based on renewability• Renewable resources• Non-renewable resources:- fossil fuel

NATURAL RESOURCES• FOREST RESOURCES

FOREST RESOURCES• Functions of forest:-

Habitat of flora and fauna Balances gaseous cycle:- Accelerate rainfall Increase water holding capacity of soil Maintain soil fertility Prevent runoff increase the percolation Provide cool atmosphere

DEFORESTATIONCauses :-• Never ending need for timber, firewood and synthetic fibre• Tunnels railways through forest• Population explosion• Hydroelectric project

• Overgrazing by cattle• Climate and weather change• Pests destroy forest

FOREST RESOURCES• Effect of Deforestation

• Soil erosion • Expansion of desert• Decrease in rainfall• Lose of fertile land• Effect on climate• Lowering of water table• Economic losses• Loss of flora and fauna• Loss of biodiversity• Increase in CO2• Shortage of fire wood cause serious misery among tribal

womenfolk

FOREST RESOURCES• Effect of Mining in Forest

• Pollution of surface and ground water resources due to the discharge of mineralized mine water

• Air pollution due to release of green house gases ex: CH4• Subsidence of land near mining area• Drying up of perennial water source• Migration of tribal people

FOREST RESOURCES• Effect of Dams/River Valley projects

• Reservoir induces seismicity• Increased incidence of water borne diseases like malaria, filaria• Rehabilitation and resettlement

• AFFORESTATION PROGRAMME• Conservation forestry : Re-growth of native vegetation• Commercial forestry:- supply of goods• Production forestry:-

• Social forestry• Agro forestry or Urban forestry

FOOD RESOURCES• Food essential component required by the body at all stages of lifeSources of food

CROPLIVE STOCKSAQUA CULTURE

CROPSFact:- 250000 species of plants / 3000 are agricultural/ 300 grown for food/100 are produced large scale

Main crops:- wheat, rice, cornWorld produces 1.6 million metric tons of wheat

LIVE STOCKIncludes domesticated animals eg:- cattle goat sheep camel

FOOD RESOURCESAQUA CULTURE

Fact:- fish and sea food contribute 70 million metric tons of high quality protein to world’s diet

WORLD FOOD PROBLEM840million people remain chronically hungry in world300million people in India are poverty stricken

5%

95%

40MILLION 800MILLION

72%

28%

300million in India500million in other country

FOOD RESOURCES• Food insecurity :- reason :- inequitable distribution of income

among the population• FOOD INSUFFICIENCYUNDER NOURISHMENT AND MALNOURISHMENT

UNDERNOURISHMENTLack of sufficient nutrients in available foodDisability to move and work

FACTS:- 2500cal/day is consumed by the worldReason for undernourishment :- dietary intake is b/w 80%-90%Major victims are children:- mental retardation, stunted growth their

dietary intake is <80%

FOOD RESOURCES• Food insecurity :- reason :- inequitable distribution of income

among the population• FOOD INSUFFICIENCYUNDER NOURISHMENT AND MALNOURISHMENT

MALNOURISHMENTLack of specific components protein, vitamin in available foodPoor countries can’t afford expensive foodDeath due to Malnourishment is not prominentPeople are less productive and suffer from brain damage

FOOD RESOURCES• OVERNUTRITIONDaily calorie intake of people in DVLPD countries=3500cal/day>>2500Over weight, high blood pressure, heart attack

CHANGES CAUSED BY AGRICULTURE on ENVAgricultural Industry :- oldest and largestProduction processing and distribution of food by industry 1ᴼ effect or On site Effect2ᴼ effect or Off site Effect

Classifications :- LOCAL, REGIONAL , GLOBAL changes

FOOD RESOURCES• LOCAL CHANGESOccur at or near the farm siteSedimentation in local river, soil erosionEutrophication :- fertilizers carried by the sedimentsSediments carries toxins REGIONAL CHANGES Large scale effect:- causes deforestation, desertificationSedimentation in major riversChanges the chemical fertility over a large area

GLOBAL CHANGESAttributed to climatic changes

FOOD RESOURCES• EFFECT OF MODERN AGRICULTURE+ve and –ve effect Fertilizers , Pesticides, insecticides Main problems are water logging and salinationProblems from:- FERTILIZERS

Inorganic component necessary :- N, P, K ca, mg , sulphur+ve Effect:-

Easy to store, handle, apply,transportLess smell, lower risk of pathogenic contamination

-ve Effect:-Artificial fertilizers cause contaminationExcessive level of Nitrates in GWPhosphate deposition cause Eutrophication, threat to water supply

FOOD RESOURCES• EFFECT OF MODERN AGRICULTUREProblems from:- PESTICIDES

PESTS:- Insects, bacteria, weeds and birds+ve EFFECTS:-

Maximises the cropsReduce post harvest lossesControl the diseases and weedsImprove the appearance of crops

-ve EFFECTS:-On Non target speciesOver usageTendency to get concentrated on food webMisuse and unsafe method of applicationCreation of new pests

FOOD RESOURCES• EFFECT OF MODERN AGRICULTUREEffect of PESTICIDES on human health

Short term :- acute poisoning and illnessLong term:- cancer, birth defects, immunological diseases

WATER LOGGINGReason:- surface flooding, high water table

SALINITYIncreased concentration of soluble salt in soilReason :- intensive agricultural practice

poor drainage