4.3 - Competition & Interdependence

• What is a key concept in ecology regarding organisms?

  All organisms have relationships with each other
• What types of relationships do mice have?

  With other mice, plants, predators, and environment
• How do mice interact with their environment?

  They breathe oxygen and burrow in soil
• What happens if the mouse population decreases?

  Predators have less food and soil quality declines
• What is a habitat?

  • The place where an organism lives
  • Examples: field, forest, basement
• What defines a population in ecology?

  All organisms of a particular species in a habitat
• Ecology is the study of the relationships between living organisms and their physical environment. Ecology considers organisms at the individual, population, community, and ecosystem level.
• What is a community in ecological terms?

  All populations of different species in a habitat
• What are biotic factors?

  Living factors like food availability and predators
• What are abiotic factors?

  Non-living factors like temperature and soil pH
• What is an ecosystem?

  • Interaction of a community of living organisms
  • With the non-living parts of their environment
• What is the main focus of ecology?

  Understanding how ecosystems function and change
• What is competition in an ecosystem?

  Organisms competing for limited resources
• What resources do animals typically need to survive?

  Space, food, water, and mates
• What resources do plants typically need to survive?

  Light, space, water, and mineral ions
• What is interdependence in ecology?

  All species depend on other species in some way
• How does a food web illustrate interdependence?

  • Shows feeding relationships within a community
  • Changes in one species affect others
• What happens if the mouse population suddenly increases?

  Grass availability decreases, affecting other species
• What might happen to hawk populations if mouse populations increase?

  Hawk populations may not increase significantly
• What is the significance of understanding ecological relationships?

  To predict knock-on effects of changes
• What should you understand about ecological relationships?

  • How species interact within ecosystems
  • Predicting effects of changes in populations
• A habitat is the place where an organisms lives. 
• A___________ refers to all of the organisms of a particular species that live in the same habitat. 

  Population
• In ecology, what is a 'community'?

  All the populations of different species that live together in a habitat
• An_________ is the interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment.

  ecosystem
• ___________is an interaction between organisms or species in which they both try to use the same limited resources.

  Competition
• Give three resources that animals compete for.


  • Food
  • Water
  • Mates
  • Territory
• Give three resources that plants compete for.

  • Mineral ions
  • Water
  • Light
  • Space
• All organisms in an ecosystem depend upon one another, with countless complex relationships between them all. 

  What do we call this concept? 

  Interdependence 
• Increase, the rabbit population is likely to increase as there will be less predation from snakes.