Ecology

• Ecology


  The scientific study of the interactions between organisms and their environment
• Environment


  Made up of biotic factors (influence imposed on an organism by other organisms) and abiotic factors (influence on an organism caused by non-living elements like temperature, soil, light, moisture, air currents)
• Levels of ecological organisation

  • Organism
  • Population
  • Community
  • Ecosystem
  • Biosphere
• Organism


  Any unicellular or multicellular form exhibiting all of the characteristics of life, an individual
• Population


  A group of organisms of the same species living in the same place at the same time
• Community


  A group of populations that inhabit a common environment and are interdependent
• Ecosystem


  A group or community of living organisms together with their non-living environment or abiotic factors
• Biosphere


  The life supporting portions of Earth composed of air, land, fresh water, and salt water
• Habitat


  The place in which an organism lives out its life
• Niche


  The role a species plays in a community; its total way of life
• Limiting factor


  Any biotic or abiotic factor that restricts the existence of organisms in a specific environment
• Biotic factors refer to the relationships living organisms share with each other
• Intraspecific competition


  Competition between organisms of the same species
• Interspecific competition


  Competition between organisms of different species
• Occupying different niches reduces competition
• Competition sometimes may help to reduce or even stabilize a population
• Predator


  An organism which feeds on another organism known as its prey
• Prey


  The organism that is fed on by a predator
• Feeding relationships

  • Producer-Consumer
  • Predator-Prey
  • Parasite-Host
• Producer


  All autotrophs (plants), they trap energy from the sun to make their own food by Photosynthesis
• Consumers

  • Primary consumers (herbivores)
  • Secondary, tertiary consumers (carnivores)
  • Omnivores
  • Decomposers
• Commensalism

  One species benefits and the other is neither harmed nor helped
• Commensalism

  • Orchids on a tree
  • Polar bears and cyanobacteria
• Parasitism


  One species (parasite) benefits and the other (host) is harmed
• Parasitism


  • Lampreys, leeches, fleas, ticks, tapeworm
• Mutualism

  Beneficial to both species
• Mutualism

  • Cleaning birds and cleaner shrimp
  • Cattle egret and cow
• Trophic level

  Each link in a food chain representing a feeding step in the transfer of energy and matter in an ecosystem
• As you move up a food chain, both available energy and biomass decrease
• Food chain

  A simple model that shows how matter and energy move through an ecosystem
• Food web

  Shows all possible feeding relationships in a community at each trophic level, representing a network of interconnected food chains
• Nutrient cycles


  • Water cycle
  • Carbon cycle
  • Nitrogen cycle
• Water cycle


  1. Evaporation

  2. Transpiration

  3. Condensation

  4. Precipitation