Species Interaction

• Population


  Group of individuals of the same species (conspecifics) living in the same area, potentially interacting
• Community


  Group of populations of different species living in the same area, potentially interacting
• Types of ecological interactions

  • Competition
  • Predation
  • Symbiosis
  • Parasitism
  • Mutualism
  • Commensalism

  
• Ecological interactions


  • Can affect distribution and abundance
  • Can influence evolution
• Competition


  Two species share a requirement for a limited resource, which reduces fitness of one or both species
• Competition


  • Green anole and brown anole competing for habitat and food, leading to resource partitioning
• Predation


  One species feeds on another, enhancing fitness of predator but reducing fitness of prey
• Predation


  • Mink hunting muskrat
  • Archerfish spraying water to knock down insect
  • Cheetah hunting gazelle
  • Lions hunting cape buffalo

  
• Symbiosis


  Two species live together, including parasitism, mutualism, and commensalism
• Parasitism


  One species feeds on another, enhancing fitness of parasite but reducing fitness of host
• Parasitism


  • Nematodes causing root galls in plants
  • Corn blight fungi
• Mutualism


  Two species provide resources or services to each other, enhancing fitness of both species
• Commensalism


  One species receives a benefit from another species, enhancing fitness of one species with no effect on the other
• Commensalism


  • Epiphytes using trees for support
  • Remoras feeding on leftovers from manta rays
  • Cattle egrets feeding on insects disturbed by grazing cattle
  • Clownfish protected by sea anemone
• Ecological Interaction Types


  • Competition (-/-)
  • Predation (+/-)
  • Herbivory (+/-)
  • Mutualism (+/+)
  • Commensalism (+/0)
  • Parasitism (+/-)

  
• Importance of Apex Predators

  1. Regulating Lesser Predators
  2. Controlling Prey Species Populations
  3. Protecting The Smaller Animals in the Ecosystem
  4. Maintaining the Balance
• Apex predator- in ecology, any flesh-eating animal that has no natural predators or enemies. Apex predators hold the top rank in a plant-herbivore-carnivore food chain and the uppermost position of an ecosystem’s trophic (or energy) pyramid, making them the final destination of energy flow in a given biological community.
• Obligate mutualism- the species are entirely dependent on each other and in others
• Facultative mutualism- they derive benefits from their relationship but could survive without each other
• Mutualism:

  Root nodules of a legume with N-fixing bacteria - facultative

  Termites & gut flagellates - obligate

  Lichens are close association between fungus and algae - obligate

  A hummingbird looks for nectar and pollen from the flower - obligate
• A green anole, native to southwestern US, and the brown anole, an introduced species from Cuba, vie for habitat and food sources. Brown anole has displaced green anole in areas like lower shrubbery and grass; while the green anole has lived up in trees and foliage. The result of competition is known as resource partitioning.
• Herbivory: A special case of predation in which the prey species is a plant
• Symbiosis: Interspecific interaction in which two species live together in a long-term, intimate association
• Competition: A lion and a hyena fighting over a carcass; regardless of "winner," both expend energy and risk being injured.
• Mutualism: A penstemon and the bee that pollinates it; the penstemon spreads its genes and the bee gets food.
• Predation or Parasitism: A fungus growing on a wild rosebush; the fungus gains energy while the rose experiences it as a disease.
• Commensalism: An orchid growing on a tree; the orchid has a support structure that protects it and makes it more accessible to pollinators, with no impact on the tree.
• Amensalism: A sunflower struggles to grow in the shade of a walnut tree; the tree experiences no impact from the presence of the sunflower.
• Neutralism: Two species of insects live on the same plant in close proximity but because they use different parts of the plant, they have no effect on each other.