Regulation growth models

• Population


  The number of people in a single area. Also applied to non-human animals, microorganisms, and plants, with specific uses in ecology and genetics.
• Population regulation


  The natural processes that limit the growth of populations of organisms
• Processes that can regulate population

  • Biotic (living)
  • Abiotic (nonliving)
• Density-dependent factors


  Factors that affect population growth and have a greater impact as population density increases (e.g. competition, predation, disease)
• Density-independent factors


  Factors that impact the per capita population growth rate regardless of the population's density (e.g. weather events, natural disasters)
• Competition for resources

  1. Intraspecific competition

  2. Interspecific competition

  3. Limits population growth and can lead to population decline if resources become scarce
• Predator-prey cycle


  1. As prey population grows, more food for predators

  2. Increase in predator population

  3. More prey susceptible to being caught, prey population declines

  4. Fewer nutrients for predators, their population declines
• Disease in dense populations

  Diseases spread more easily due to increased contact between infected and healthy individuals, leading to outbreaks that can significantly reduce population size
• Density-independent factors


  • Impact the per capita population growth rate regardless of the population's density, do not depend on population size
• Density-independent factors

  • Natural disasters
  • Deforestation
  • Introduction of invasive species
• Deforestation as a density-independent factor


  Limits populations through habitat loss, reduced food availability, disrupted breeding and nesting, fragmentation, and microclimate change
• Invasive species


  Can disrupt food webs and outcompete native species, leading to population declines in the latter. Reproduce quickly and spread easily without natural predators.
• Exponential growth


  Population size increases rapidly and continuously over time in the absence of limiting factors, represented by a J-shaped curve
• Logistic growth


  Initial exponential growth phase followed by stabilization of population size as it approaches carrying capacity, represented by an S-shaped curve