ECOLOGY

• Ecology


  The branch of biology that studies the relationships and interactions of living things with one another and with their external environment
• Ecology comes from the Greek word oikos, which means "house," and logos, which means "study"
• Ecologists


  • They ask questions about what animals and plants live in an area, how they interact with one another and with their physical environment, and what changes the area will undergo over time
• Ecologists study both nonliving (physical) environment and living (biological) environment
• Layers of ecological organization

  • Biosphere
  • Biome
  • Ecosystem
  • Community
  • Population
  • Habitat
  • Niche
• Biosphere


  The part of Earth that supports life, including the top portion of Earth's crust, all the bodies of water on Earth's surface, and the surrounding atmosphere
• Biome


  A set of ecosystems occupying large ecological areas, sharing distinct abiotic characteristics among its unique flora and fauna
• Ecosystem


  An area where living things interact with one another and with their environment
• Community


  Different species of organisms that interact with one another in a given area
• Population


  A group of organisms of the same species that live in a community
• Habitat


  The actual place or type of environment where an organism or a population lives
• Niche


  The role of an organism in its habitat
• Abiotic factors


  Nonliving parts of an ecosystem, such as soil, water, air, light, temperature, and topography
• Biotic factors


  Living parts of an ecosystem, such as animals, plants, and other organisms
• Abiotic factors affecting living organisms in an ecosystem

  • Light
  • Temperature
  • Water
  • Oxygen
  • pH
  • Salinity
• Producers


  Organisms that can manufacture their own food, such as green plants and certain microorganisms
• Consumers


  Organisms that cannot make their own food and depend on producers for food and energy
• Types of consumers


  • Herbivores
  • Carnivores
  • Omnivores
  • Scavengers
• Detritivores


  Organisms that eat fragments of dead organic matter and return them as nutrients to enrich the soil
• Decomposers


  Microorganisms, such as fungi and bacteria, that break down dead bodies of organisms into simpler substances
• Carnivores


  Animals that eat the flesh of other animals
• Omnivores


  Organisms that eat both plants and animals
• Scavengers


  Consumers that feed on decaying bodies of dead animals
• Scavengers


  • Hyenas
  • Vultures
• Detritivores


  • Worms
  • Insects
• Decomposers


  Microorganisms, such as fungi and bacteria, that break down dead bodies of organisms into simpler substances to enable the materials locked up in them to be returned to the soil and be used again by green plants
• Without decomposers, the world will be filled with plant and animal wastes, dead bodies, and organic garbage
• In the natural environment, the wastes of another organism can be used as resources for other organisms as nutrients that can be continuously recycled
• Nutrients recycled in nature

  • Carbohydrates
  • Lipids
  • Proteins
  • Water
• Photosynthesis


  1. Solar energy (light)

  2. CO2

  3. H2O

  4. Carbohydrates

  5. Heat energy
• Aerobic respiration


  1. Glucose

  2. Oxygen

  3. CO2

  4. H2O

  5. ATP (chemical energy)
• Roles organisms play in an ecosystem

  • Producer
  • Consumer
  • Herbivore
  • Carnivore
  • Omnivore
  • Scavenger
  • Parasite
  • Decomposer
• Energy from the sun ultimately supplies all energy needed by all organisms to survive
• Food chain


  A way of describing the flow of energy in food through a community, with arrows showing the direction of energy flow
• Trophic levels in a food chain

  • Producers
  • Primary consumers (herbivores)
  • Secondary consumers (carnivores)
  • Tertiary consumers (top carnivores)
• Nature cannot usually support food chains that are longer than three or four links because in each link, the amount of energy available to be consumed decreases
• Food web


  A network of interconnected food chains in a community or ecosystem
• Energy pyramid


  A block diagram that illustrates the flow of energy through an ecosystem, showing the decrease in available energy at each successive trophic level
• About 90 percent of energy is lost to the environment as food is transferred from one trophic level to the next
• A vegetarian diet is more energy efficient than a meat-based diet