übertool: web applications for ecological risk assessment (beta version)
Cloud-based environmental models used by the USEPA for evaluating pesticide risks to ecosystems under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Endangered Species Act (ESA).
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Exponential Model Overview


Exponential model (a.k.a. Malthusian growth model) is associated with the name of Thomas Robert Malthus (1766-1834), who first realized that any species can potentially increase in numbers according to a geometric series. In 'Essay on the Principles of Pupulation', Malthus argued that in the absence of any constraints, human population will grow in a multiplicative manner until the depletion of food.


Assumptions of Exponential Model:

  • Continuous reproduction (e.g., no seasonality)
  • All organisms are identical (e.g., no age structure)
  • Environment is constant in space and time (e.g., resources are unlimited)