ecology notes - Ecological Niche Ecology the relationships...

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Ecological NicheEcology– the relationships between organisms and their environments including biological as well as physical and chemical properties of environment.Aims of ecology are to describe and understand the distribution, abundance and production of organisms in their environment. With the ultimate goal of being able to predict changes in environment and organisms.; when something may occur and why. Observation: five species of warblers co-existed in the same habitat. Through careful observation it was noticed that the warblers lived in same tree but did not spend time in the same part of the tree at the same time. They were living in different nichesThe Niche: the environmental factors that influence the growth, survival, and reproduction of a species. All factors necessary for its existence – when, where and how a species makes its livingFactors influencing where organisms live in their environment includeResources (N, P, Ca, etc) foodPresence/absence/quantity of light (photoautotroph are influenced by light availability)Other species and predatorsWaterTemperatureTemperature affects the metabolic activities of all organisms because the biochemistry of cells is catalyzed by enzyme and their activity is influenced by ambient temperature. Enzyme reaction rates are proportional to temperature, have higher catalysis rates at higher temperature. At very high temperature enzymes will degrade and catalysis rate falls off. Acclimation to temperature– physiological changes in response to temperature changes. For example atriplex lentriformis(a desert shrub) grown at two temperatures 43/30 and 23/18 (Day/Night). Temperature dependence of microbial growthon the organism level. Environmental heterogeneityMicroclimateis the climate experiences at scales of kilometers, or meters, or centimeters (shade of a tree on a sunny day). Influenced by many factors including altitude (T declines as high increases) Vegetation. Soil colouroWhite sand beach reflects all wavelengths of visible lightoBlack sand absorbs all wavelengths of lightAspect (north facing vs. south face slope)Aquatic vs. terrestrial environment (aquatic environments show less temperature variation than terrestrial environments)Habitat – the physical place where organisms live (eg. Tropical rainforest, bottom of a lake, hot spring)Niche – exist within habitats. Includes physical factors such as temperature and moisture, biological factors such as resources and predators. The intensity of competition between species suggest the degree to which their niches overlap.Law of minimums: states that each species has a minimum requirement for every factor necessary for its survival and growth. Eg. Minimum T or lightLaw of tolerancestates that even factors necessary for survival and growth can be stressful when present in too great anamount
1. The availability of niches within a habitat varies in times and space – which influences the abundance and distribution of the speciesFeeding niches of finches show a relationship between body size and seed size. The kinds of seeds eaten by the bird

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