OUR ENVIRONMENT

What are environmental issues? Does environment influence us ? Or Do we influence the environment ? Whatever ………. No organism can survive without an environment, so essential it is for all organisms. Every organism has a right on the environment,just like us the HOMO SAPIENS.

Human interventions: What happens when we add waste to our environment? Perform an activity of collecting wastes generated in your house and bury it in a pit and leave it for 15 days ……….What happens? Types of wastes : 1 Biodegradable 2 Non biodegradable

BIODEGRADADBLE WASTES They are acted upon by enzymes and broken down by biological processes of bacteria and saprophytes into simple elements and recycled back in to the environment so they will replenish the environment. Eg paper,vegetables

BIODEGRADABLE WASTES

NON BIODEGRADABLE WASTES They are substances which are not acted upon by enzymes and cannot be broken down into simple elements so they persist in environment for long and pollute the environment. Eg plastics

N0NBIODEGRADABLE WASTES

ECOSYSTEM All the interacting organisms in an environment with the non living components of an area form ecosystem. COMPONENTS OF ECOSYSTEM 1 ABIOTIC FACTORS(Physical factors ) 2 BIOTIC FACTORS(Living Organisms)

TYPES OF ECOSYSTEMS Natural ecosystems eg pond, lakes Manmade ecosystems eg aquarium, garden, cropfields In all ecosystems there is interaction between living and non living organisms then only it is a self sustaining unit.

MANMADE ECOSYSTEM

BIOTIC COMPONENTS IN AN ECOSYSTEM PRODUCERS All green plants and blue green algae which produce food by photosynthesis.

CONSUMERS All organisms which consume food produced directly from producers or indirectly by feeding on other consumers. Herbivores (plant eaters, eg goat,deer carnivores (flesh eaters eg lion,snake)omnivores eat both plants and animals (humans)

DECOMPOSERS(NATURAL CLEANSERS OF ENVIRONMENT) They include the micro organisms which break down dead and and waste remains into simple elements and return to environment so that plants can utilise it again.

DECOMPOSERS

FOOD CHAIN The process of eating and being eaten can be represented as a series called food chain. Each step in a food chain is called a trophic level and energy flows from one trophic level to next (UNIDIRECTIONAL FLOW OF ENERGY) First Trophic level : Autotrophs or producers Second trophic level : Herbivores or primary consumers Third trophic level : Secondary consumers. Fourth trophic level: Tertiary consumers.

FOOD CHAIN

TYPES OF FOOD CHAINS Forest food chain Grass …..>deer……>tiger Aquatic food chain Aquatic plants……>insects……>small fish…..>large fish…..>crane Grass land food chain Grass………>insect………>frog…….>snake……>eagle

FLOW OF ENERGY IN AN ECOSYSTEM Flow of energy is UNIDIRECTIONAL. Green plants capture ONE PERCENT of solar energy and convert it into food energy. Only TEN PERCENT of energy is transferred from one trophic level to next remaining ninety percent is lost to environment as heat energy. Food chains have very few steps because very little usable form of energy reaches higher trophic levels and no of producers are more.

UNIDIRECTIONAL FLOW OF ENERGY

FOOD WEBS When two or more food chains are interconnected it forms a FOOD WEB Then length and complexity of food chains vary because it is not a straight chain but a branching chain

BIOLOGICALMAGNIFICATION or BIOACCUMULATION Pesticides are applied to crops They are washed into water bodies or soil. They are absorbed by aquatic animals and plants and enter food chain Pesticides are not biodegradable so get accumulated in food chain at each higher trophic level so in humans maximum. This is called bioaccumulation.

BIOMAGNIFICATION

OZONE LAYER Ozone is formed when UV radiation acts on oxygen and splits molecular oxygen and some oxygen atoms combine with oxygen to form ozone. Ozone protects the earth as a shield from UV radiations which are harmful to organisms especially to man it causes skin cancer.

FORMATION OF OZONE

DEPLETION OF OZONE LAYER In 1980 the ozone layer depletion started due to CFC ( CHLOROFLUROCARBONS) present in refrigerants and fire extinguishers. UNEP (United Nations Environment Programme) in 1987 made an agreement to freeze CPC

OZONE HOLE

WASTE GENERATION Wastes are generated in large amount both biodegradable and non bio degradable. Biodegradable can be degraded and recycled and non bio degradable cannot be recycled and so they persist in environment.

SEGREGATE WASTE BEFORE DISPOSAL

PREPARED BY LINI NAIR,PGT BIO KV NO2 KASARGOD