BISC 313 Lecture Notes - Lecture 4: Trophic Cascade, Ecological Niche, Continental Drift
1 Nov 2017
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Document Summary
Populations are dynamic entities that vary in size over time and space. Population: group of interacting individuals of the same species living in the same place and time. Distribution: geographic area where individuals of a species occur. Abundance: number of individuals in a given population. Can be reported as population size or density. Gives instantaneous population measures, but populations are dynamic--distribution and abundance change over time and across space. Abiotic features: include moisture, temperature, ph, sunlight, nutrients, salinity. Abiotic features determine the boundary of biomes: large-scale communities shaped by the physical environment, often characterized by dominant flora and fauna. Terrestrial biomes are characterized by the growth form of dominant vegetation-- determined by precipitation and temperature. Biological zones in freshwater systems are associated with the velocity, depth, temperature, clarity and chemistry of the water: marine biological zones are determined by ocean depth, light availability, salinity, and stability of the bottom substrate.
