9.3

• What is the definition of distribution in ecology?

  The number of individuals per unit of area or volume
• How can biomass be measured in ecology?

  Biomass can be measured as the mass of living matter per unit of area
• What is a population in ecological terms?

  A population is a number of individuals of the same species which live in a defined geographic area
• What factors affect population growth?

  Population growth is affected by natality, mortality, immigration, and emigration
• What is exponential population growth?

  Exponential population growth is theoretical population growth that increases exponentially under ideal conditions
• What assumptions are made in modeling theoretical population growth?

  It is assumed that the rates of immigration and emigration are equal
• What happens to a population when birth rates and death rates balance each other out?

  This balance is referred to as the carrying capacity of the population
• What factors can affect the carrying capacity of an environment?

  Weather, climate change, major environmental changes, and fluctuations in food species or competitors can affect carrying capacity
• What is the tolerance range in ecology?

  The tolerance range is the range of environmental conditions that an organism can withstand
• What can happen to organisms outside their ideal tolerance range?

  Organisms may experience stress, leading to delayed development, reduced survival and reproduction rates, and decreased lifespan
• What is the zone of intolerance for an organism?

  In the zone of intolerance, an organism will die
• What are some major changes to the environment that can affect population size?

  Natural disasters and human-made changes, such as construction, can affect population size
• How do organisms interact with their environments in ecosystems?

  Organisms interact with both their abiotic and biotic environments
• What are biotic environments in ecosystems?

  Biotic environments include relationships between organisms of the same species and those of different species
• What are the different types of relationships in ecosystems?

  • Parasitism
  • Mutualism
  • Commensalism
  • Allelopathy
  • Predatory-prey relationships
  • Competition for resources
• What is parasitism in ecological terms?

  Parasitism is a trophic relationship where a parasite feeds on its host's tissue or food
• What are the two types of parasites?

  Endoparasites live inside the host, while ectoparasites live on the host
• What is mutualism?

  Mutualism is a relationship where both parties gain some benefit
• What is commensalism?

  Commensalism is a relationship where one member gains while the other neither suffers nor gains
• What is amensalism?

  Amensalism is a relationship that is detrimental to one species and neutral to another
• What is allelopathy?

  Allelopathy is when an organism releases chemicals that influence the growth of other organisms
• What are allelochemicals?

  Allelochemicals are the chemicals released by organisms that influence the growth of other organisms
• What is predation?

  Predation involves the capture and killing of other animals for food
• How does the number of predators relate to the number of prey?

  There is a strong correlation between the number of predators and the number of prey
• What are density-dependent factors?

  Density-dependent factors are limiting factors that cause the population not to increase exponentially
• How does competition affect population size?

  Competition occurs when one organism or species is more efficient at gaining access to a limited resource
• What is crowding in ecological terms?

  Crowding affects different species in different ways, potentially causing fewer offspring and affecting immune systems
• How do parasites affect their hosts?

  Parasites may reduce the host's ability to reproduce, lifespan, and make the host more prone to disease
• How does infectious disease spread in populations?

  Disease can spread more rapidly in denser populations
• What factors affect the rate at which a pathogen spreads?

  The rate at which a pathogen spreads depends on environmental conditions and genetic diversity of the host population