Aartee Mishra is teaching live on Unacademy Plus
Environment Book Summary Presented B Aartee Mishra
CHAPTER 2 FUNCTIONS OF AN ECOSYSTEM (Part-2)
POLLUTANTS AND TROPHIC LEVEL Pollutants especially nondegradable ones move through the various trophic levels in an ecosystem. Non degradable pollutants mean materials, which cannot be metabolized by the living organisms. Example: chlorinated hydrocarbons. We are concerned about these phenomena because, together they enable even small concentrations of chemicals in the environment to find their way into organisms in high enough dosages to cause problems. Movement of these pollutants involve two main processes: i) Bioaccumulation ii) Biomagnification.
Bioaccumulation Bioaccumulation It refers to how pollutants entera food chain. . In bioaccumulation there is an increase in concentration of a pollutant from the environment to the first organism in a food chain. Biomagnification TIME Biomagnification refers to theContaminant levels tendency of pollutants to concentrate as they move from one trophic level to the next. Thus in biomagnification there is an increase in concentration of a pollutant from one link in a food chain to another. Contamint leels Biomagnification
In order for. biomagnification to occur, the Fish-eating birds DDT 5 ppm) pollutant must be: long-lived, mobile, soluble in fats, biologically active. E.g. DDT It is traditional to measure the amount of Large Ash DDT 2 ppm) pollutants in fatty tissues of organisms such as fish Small ish DDT O.5 ppm) In mammals, we often test the milk produced by ,. ) (700p females, since the milk has a lot of fat in it and is often more susceptible to damage from toxins (poisons) ( DDT 0.04 ppm) Water DDT O.003 ppm) Figure Biomagnification of DDT In an aquatie food chain
BIOTIC INTERACTION Biotic Interaction Organisms living in this earth are interlinked to each other in one way or other. The interaction between the organisms is fundamental for its survival and functioning of ecosystem as a whole. S.No. IypeSpices 1 Secies 2 Mutualism 2. Commensalism)(0) 3. Competition 4. Predation 5. Parasitism 6.Amensalism Types of biotic interaction Mutualism: both species benefit. Example: in pollination mutualisms, the pollinator gets food (pollen, nectar), and the plant has its pollen7. Neutralism ransferred to other flowers for cross- Beneited fertilization (reproduction). (-Harmed (0) Neither Benefited nor harmed