Chapter 57

• Species interactions


  Occur between two different populations that live in the same area
• Species interactions


  • Can limit population growth due to limiting factors such as resources, space, etc.
  • Aid in evolution ("survival of the fittest")
• Intraspecific interactions

  Occur between individuals of the same species
• Interspecific interactions

  Occur between individuals of different species
• Types of species interactions

  • Competition
  • Predation
  • Herbivory
  • Parasitism
  • Mutualism
  • Commensalism
  • Amensalism
• Competition


  Interaction between two or more species in which both organisms rely and compete for the same resource(s) and are harmed to some extent
• Intraspecific competition example

  • eBay; if many people bid on the same item, it drives the cost of the item higher. But, if only one person bids on the item, then that person would win the auction for a very low amount.
• Interspecific competition example

  • Zebras and gazelles grazing on the same grassland
• Predation


  action of the predator resulting in the death of its prey
• Herbivory


  Consumption of plant material by animals (herbivores are animals that eat plants)
• Parasitism


  Interaction involving an organism (called the parasite) that lives in, on, or with another organism (called the host) that directly or indirectly harms the host
• Mutualism

  Interaction in which both species receive a benefit from the other
• Commensalism

  Interaction in which one species benefits and the other is neither harmed nor benefited
• Amensalism


  Interaction in which one species is harmed and the other is unaffected (does not benefit nor harm)