PACKET #21 CHAPTER #6 Introduction to Ecology

Introduction Ecology  The scientific study of the interactions between organisms and the environment  Ecologists, under the umbrella of ecology, pose questions and devise hypotheses about ecosystems.  Where does a species of organisms live?  Why do they live there?  How many of those organisms are there?

Ecosystem Complete community of living organisms and the nonliving materials of their surroundings Consists of  Biotic components  Living organisms  Abiotic components  Non-living factors Light Temperature Water

Levels of Ecological Study Organismal Ecology  Study of individual organisms’ behavior, physiology, etc. Population Ecology  Study of populations in relation to the environment  Environmental influences  Population density and distribution  Age of members How do populations grow? Is there a limit to the number of organisms within a population? Community Ecology  Study of interactions between organisms, of various populations, at a particular site or in a specific area Ecosystem Ecology  Study of movement of energy and matter through ecosystems

Man, His Environment & Impact on Ecosystems

Question How would you describe the major human influences on the environment? Primitive man  Affected environment  Hunting  Fishing  Removing trees for fires and shelters There was a demand for land to cultivate and harvest crops and to grow communities Cultivation of crops done with domestic animals and they had to be fed as well Leaving less for human consumption More modern man  Discovery of fossil fuels  Machines were now used to help grow more crops  Population became larger  Fertilizers, pesticides and “rapid” transportation developed  Brought the problem of pollution  Nuclear energy was developed with its consequent environmental problems

Exploitation of Natural Resources Agriculture  Fire used to clear large areas of land for planting  Vegetation destroyed and replaced by mono-culture  Field of cereal crops replaced a forest of oak  Placed a demand on soil nutrients after growing same crop for a number of years How could this problem be avoided? Rotating crops  Excess use of fertilizers Caused pollutants to run off into rivers due to leaching and draining  Weeds and pests also compete for resources and with only one main species as competition, soil nutrient problems also arise

Renewable Resources Renewable resources are basically things that grow and are therefore replaced.  Does not mean that the resources are inexhaustible  If the resource is utilized too much, at too much of a great rate, they will most certainly diminish and even disappear altogether  Reason why there are harvesting seasons  Lobster  Crab  Salmon  What is your opinion on how man has utilized these renewable resources?

Non-renewable Resources Not replaceable  Oil  Gas  Coal  Mineral ores  Will oil and gasoline run out? Some believe so!

Human Population Explosion Questions posed by scientists?  Will the human population reach it’s carrying capacity? The explosion in human population has resulted in: -  An increase in the use of non-renewable resources  An increase in land, air and sea pollution as a result of fuel combustion by-products Today, finding a cost effective measure, where resources are not totally used up, is not easy and there are many arguments between conservationists and industry

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