APES UNIT 1 - Introduction to Ecology

• What is an ecosystem?

  All the biotic (living) and abiotic (non-living) components of an ecosystem and how they interact.
• How can the size of an ecosystem vary?

  An ecosystem can be as small as a tidal pool or as large as a kelp forest, depending on the observer's definition of its boundaries.
• What does the term habitat refer to?


  Where an organism lives.
• What is a niche in ecology?


  The role an organism plays in its environment, considering all biotic and abiotic interactions.
• What are the types of ecosystem interactions?

  1. Predator - Prey Interactions
  2. Symbiotic Interactions
  3. Competitive Interactions
• How do predator-prey interactions affect populations?


  They keep each other's populations in check, leading to "boom and bust" cycling.
• What type of feedback loop do predator-prey interactions represent?

  This is an example of a negative feedback loop.
• What is a limiting resource factor?


  Any resource in the ecosystem where demand is greater than supply.
• How does a limiting resource factor affect organisms?

  It constrains the growth or abundance of organisms.
• What is intra-specific competition?

  Competition that occurs between the same species.
• What is inter-specific competition?

  Competition that occurs between different species.
• What does the Competitive Exclusion Principle state?

  If two different species living in the same territory start to fill the same ecological niche, they will compete for the same resources.
• What happens when two species compete for the same resources?


  One will win and the other will be displaced.
• What is resource partitioning?

  Every species has a unique niche using slightly different resources to reduce competition with other species.
• How does habitat loss affect ecosystems?

  It reduces resource availability, forces niches to overlap, and increases competition.
• What is a keystone species?

  A species that, if removed, results in the health of an ecosystem drastically declining.
• What is a trophic cascade?

  Removal of top predators resulting in reciprocal changes in other populations due to the interconnectedness of food webs.
• How did the re-introduction of wolves affect Yellowstone National Park?

  It brought balance back to biotic and abiotic factors.
• What role does the gray wolf play in Yellowstone National Park?

  The gray wolf is a keystone species in Yellowstone National Park.
• What are ecosystem engineers?

  • Species that modify their environment
  • Other organisms rely on these changes to live or thrive
  • Also considered a keystone species
• What are indicator species?

  • Very sensitive to certain environmental conditions
  • Their presence, absence, or health indicates the health of an ecosystem
• What is the range of tolerance for a species?

  Every species has a range of ecological conditions in which they can survive.
• What can happen if there is a drastic change in an environmental condition?

  It can result in extinction for species with a narrow range of tolerance.
• What are the differences between generalists and specialists?

  Generalists:

  • Broad niche
  • Wide range of tolerance
  • Adapt to change easily

  
  

  Specialists:

  • Small niche
  • Narrow range of tolerance
  • More susceptible to extinction