Ecology

• What is the definition of a population in ecology?

  A population is defined as a group of organisms of the same species living in the same place at the same time.
• What does a community include?

  A community includes all of the populations living in the same area at the same time.
• What is a habitat?


  A habitat is the place where an organism lives.
• How is an ecosystem defined?

  An ecosystem is defined as all the biotic factors and all the abiotic factors that interact within an area at one time.
• How can quadrats be used to estimate the population size of an organism in two different areas?

  • Quadrats are rectangular frames of known dimensions.
  • Place quadrat randomly within sampling area.
  • Count the number of members of the same species within the quadrat.
  • Repeat this numerous times within the sampling area using the same size quadrat.
  • Repeat the process in another area to compare results.
  • Population size = (Total area/sampled area) × Number of organisms.
• How can quadrats be used to sample the distribution of organisms in their habitats?

  • Quadrats are rectangular frames of known dimensions.
  • Place quadrat randomly within sampling area.
  • Count the number of members of the same species within the quadrat.
  • Repeat this numerous times within the sampling area using the same size quadrat.
  • Repeat the process in another area to compare results.
  • Population size = (Total area/sampled area) × Number of organisms.
• What are abiotic factors in an ecosystem?

  Abiotic factors are non-living environmental factors that can affect organisms in an ecosystem.
• How do abiotic factors affect species in an ecosystem?

  Abiotic factors can affect a range of species as each organism is adapted to certain environments.
• What are biotic factors?


  Biotic factors are interactions between living organisms.
• How do biotic factors affect species?

  Biotic factors affect all species as they can be food for predators or hosts to diseases that can affect population sizes.
• What are the different trophic levels in an ecosystem?

  • Producers: Organisms that produce their own organic nutrients (e.g., plants produce glucose via photosynthesis).
  • Primary Consumers: Herbivores that feed on plants (producers).
  • Secondary Consumers: Predators that feed on primary consumers.
  • Tertiary Consumers: Predators that feed on secondary consumers.
  • Decomposers: Organisms that release digestive enzymes on dead organisms or non-living organic matter for energy.
• What is a food chain?


  • A food chain shows the feeding relationships between living organisms.
  • Example:
  • Flower (Producer) → Snail (Primary Consumer) → Frog (Secondary Consumer) → Fox (Tertiary Consumer).
• How is energy transferred along a food chain?

  As one organism consumes another, energy and substances like fat and vitamins get transferred to the consumer.
• Why is only about 10% of energy transferred from one trophic level to the next?

  Only about 10% of energy is transferred due to factors like undigested food, heat loss during respiration, and energy used for life processes.
• What is biodiversity?


  Biodiversity is the range and variety of different species of organisms on Earth, or within an ecosystem.
• How can biodiversity be measured using quadrats?

  • Use 2 tape measures to lay out your first survey area (e.g., 10m x 10m).
  • Use a random number generator to create coordinates for placing the first quadrat.
  • Count the number of different species found within that quadrat.
  • Repeat this process until data is collected for 10 quadrats.
  • Repeat these steps for the second survey area.