zThe Biosphere zGeneral Objectives

Sub-topic (a) Investigating an Ecosystem zDescribe the main parts of an ecosystem zAn ecosystem is a natural biological unit made up of living and non-living parts. zNon-living factors (abiotic) zLiving factors (biotic) zDescribe techniques used to sample organisms zPitfall traps zPooter zTree beating

zIdentify two abiotic factors zpH zmoisture ztemperature zLight Intensity zDescribe methods of measuring abiotic factors zLight Intensity: light meter zMoisture: moisture meter zTemperature: thermometer zpH: pH meter

zDescribe the effect of an abiotic factor on the distribution of organisms zLight zIncreased numbers of daisies in a unshaded area compared to a shaded area. The availability of light is effecting their distribution.

Sub-topic (b) How it works zDefine the words; habitat, population, community and ecosystem zHabitat: place where an organism lives zPopulation: group of organisms of one species in an ecosystem zCommunity: all the plants, animals and micro- organisms that live together in an ecosystem zEcosystem: natural biological unit made up of living and non-living parts

zDescribe what is meant by a producer and a consumer zProducer zGreen plant that uses light energy to make its own food. zConsumer zOrganism that depends on another living thing as a food source. zGive an example of a food chain and a food web. zRemember they always start with a producer (green plant). Ensure the direction of the arrows is understood.

zExplain the meaning of the arrows in a food web zThe arrows represent the direction of ‘energy flow’. zDescribe two ways in which energy is lost from a food web zHeat production zMovement zChemical Reactions zWaste production

zState the effect of birth rate and death rate on a population zIf the birth rate is greater than the death rate then the population will increase. zIf the death rate is greater then the birth rate then the population will decrease. zIf the birth rate and death rate are equal the the population will remain steady. zList three factors which can limit growth in a population zLimited supply of food and water zLack of space zDisease

zState how competition comes about and describe its effects zCompetition can occur when a resource is in limited supply. In an natural ecosystem competition can occur when two or more members of a community need a particular resource. zWhenever competition occurs some of the competitors grow more slowly than others. These ‘weaker’ individuals lose out in the struggle for existence and often die before reaching reproductive age.

zExplain why nutrient cycles are important. zNutrients are chemical substances such as nitrogen, oxygen, mineral salts and carbon dioxide. zNutrient cycling is important because the the supply of many chemicals is limited. If the chemicals remain ‘locked up’ in dead bodies and wastes, supplies would soon run out.

zSub-topic (c) Control and Mangement zState that pollution affects air,fresh water, sea water and land. zName the main sources of pollution. zIndustry and coal fired-power stations. zCar exhausts zHomes and farms zAgriculture zOil tankers zNuclear power stations

zGive an example of one way to control pollution zControlling acid rain zScrubbing the fumes produced before releasing them. zFuel burners can be redesigned to operate at lower temperatures and produce less of the poisonous gas. zAdd lime to water to bring pH in water back to a level that fish can tolerate. zDescribe the importance of organic waste to micro-organisms. zBacteria and fungi use organic waste as a food source.

zDescribe the effects of micro-organisms on available oxygen zAs micro-organisms breakdown organic waste they use up the available oxygen. Therefore, in highly polluted areas oxygen concentrations will be low. zName two examples of poor management of natural resources and suggest improvements zUse of vast quantities of grain to feed livestock. zThis could be improved by encouraging people to eat less meat. Feed less grain to animals and more to starving people.

zOvergrazing of grassland zThis could be improved by providing economic support to plant shelter beds for trees and resilient grass cover. zDescribe how the effect of poor management of natural resources can produce problems. zOver use of pesticides can lead to them entering the food chain. zMalnutrition. zOvergrazed plants die which can lead to increased desert land.