ppt. on ecology

Information about ppt. on ecology

Published on November 14, 2008

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Ecology and Ecosystem : Ecology and Ecosystem by: Flora May Esdrelon What is ecology? : What is ecology? is the scientific study of the distribution and abundance of life and the interactions between organisms and their natural environment The environment of an organism includes physical properties: : The environment of an organism includes physical properties: which can be described as the sum of local abiotic factors such as insolation (sunlight), climate, and geology biotic ecosystem, which includes other organisms that share its habitat Scope : Scope Ecology is usually considered as a branch of biology, the general science that studies living organisms. Organisms can be studied at many different levels, from proteins and nucleic acids (in biochemistry and molecular biology), to cells (in cellular biology), to individuals (in botany, zoology, and other similar disciplines), and finally at the level of populations, communities, and ecosystems, to the biosphere as a whole; these latter strata are the primary subjects of ecological inquiry Levels of ecological organization : Levels of ecological organization Biosphere Region Landscape Ecosystem Community Interactions Population Individual What is ecosystem? : What is ecosystem? It is a natural unit consisting of all plants, animals and micro-organisms (biotic factors) in an area functioning together with all of the non-living physical (abiotic) factors of the environment Examples of Ecosystems : Examples of Ecosystems Coral Reef Human Ecosystem Aquatic Ecosystem Chaparral Greater Yellowstone Ecosystem Components of Ecosystem : Components of Ecosystem Energy Flow Through the Ecosystem : Energy Flow Through the Ecosystem Nutrients Cycle : Nutrients Cycle Homeostasis : Homeostasis It is the property of either an open system or a closed system, especially a living organism, that regulates its internal environment so as to maintain a stable, constant condition. Multiple dynamic equilibrium adjustment and regulation mechanisms make homeostasis possible . Properties of homeostasis : Properties of homeostasis They are ultrastable ; Their whole organisation, internal, structural, and functional, contributes to the maintenance of equilibrium They are unpredictable (the resulting effect of a precise action often has the opposite effect to what was expected). Main examples of homeostasis in mammals are as follows: : Main examples of homeostasis in mammals are as follows: The regulation of the amounts of water and minerals in the body. This is known as osmoregulation. This happens in the kidneys. The removal of metabolic waste. This is known as excretion. This is done by the excretory organs such as the kidneys and lungs. The regulation of body temperature. This is mainly done by the skin. The regulation of blood glucose level. This is mainly done by the liver and the insulin secreted by the pancreas. Mechanisms of homeostasis: feedback : Mechanisms of homeostasis: feedback Negative feedback is a reaction in which the system responds in such a way as to reverse the direction of change. Since this tends to keep things constant, it allows the maintenance of homeostasis. For instance, when the concentration of carbon dioxide in the human body increases, the lungs are signaled to increase their activity and expel more carbon dioxide. In positive feedback, the response is to amplify the change in the variable. This has a de-stabilizing effect, so does not result in homeostasis. Positive feedback is less common in naturally occurring systems than negative feedback, but it has its applications. For example, in nerves, a threshold electric potential triggers the generation of a much larger action potential

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