Chapter 2

• Ecosystem


  An interacting group of natural elements and the organisms in a given environment
• Ecosystem


  • It possesses both living (biotic) and non-living (abiotic) components of the environment
  • Living things respond and adapt to the non-living conditions in their environment to maintain their homeostasis or their steady-state condition
• A coral reef is a marine ecosystem, illustrating the biotic and abiotic components
• Biotic components


  The living things present in the ecosystem
• Biotic components

  • Autotrophs
  • Heterotrophs
• Autotrophs


  Require only inorganic nutrients and an outside energy source to produce organic nutrients for their own use and indirectly for all the other members of the ecosystem
• Producers


  Autotrophs that produce energy
• Photosynthetic organisms


  • Algae
  • Green plants such as trees
• Chemosynthetic autotrophs


  Obtain energy by oxidizing inorganic compounds such as ammonia, nitrites, and sulfides, and they use this energy to synthesize organic compounds
• Chemosynthetic autotrophs


  • Tubeworms
• Heterotrophs


  Need preformed source of organic nutrients
• Consumers


  Heterotrophs that consume food
• Herbivores or Consumers

  • Herbivores
  • Carnivores
  • Omnivores
  • Scavengers
• Detritus


  Organic remains in the water and soil that are in the final stage of decomposition
• Detritus feeders


  • Marine fan worms
  • Earthworms
• Decomposers


  Use their digestive secretions to chemically breakdown dead organic matter including animal wastes in the external environment
• Without decomposers, plants would be completely dependent only in physical processes, such as the release of minerals from rocks to supply them with inorganic nutrients
• Abiotic components


  The non-living components of the ecosystem
• Abiotic components

  • Sunlight
  • Water
  • Temperature
  • Wind
  • Atmospheric gases
• Sunlight


  • The primary source of energy in nearly all ecosystems
  • Used by green plants during photosynthesis to make carbohydrates from atmospheric carbon dioxide and water
• Photoperiodism


  The response of plants to day and night
• Plant groups based on photoperiodism

  • Long day plants
  • Short day plants
  • Day neutral plants
• Crepuscular


  Active during twilight hours, at dawn and dusk
• Nocturnal


  Active only at night
• Diurnal


  Demonstrate activity during the day
• Water


  The universal solvent and the basis of all life on our planet
• Plant groups based on water requirement

  • Hydrophytes (water-loving plants)
  • Mesophytes (moderate water-loving plants)
  • Epiphytes (Water from air)
  • Xerophytes (plants loving dry condition)
  • Halophytes (saltwater-loving plants)
• Temperature


  Measure of hotness or coldness of the body, substance or the environment
• Poikilotherm


  Animal whose internal temperature varies along with that of the ambient environmental temperature
• Homeotherms


  Animal species that maintains thermal homeostasis, they keep their body temperature at a roughly constant level, regardless of the ambient temperature
• Hypothalamus


  Acts as a receptor in temperature regulation
• Corrective mechanisms in temperature control

  • Increased sweating
  • Vasodilation
  • Vasoconstriction
• Thermoperiod


  The daily temperature change
• Plants produce maximum growth when exposed to a day temperature that is 10 to 15 °F higher than the night temperature
• High temperatures caused increase respiration, sometimes above the rate of photosynthesis
• For growth to occur, photosynthesis must be greater than respiration
• Wind


  The horizontal movement of the air that tends to equalize lateral difference in temperature and pressure

  • Blows off from high pressure to low pressure
• Monsoons


  Large scale seasonal wind
• Monsoon seasons in the Philippines

  • June to October - Southwest Monsoon (Habagat)
  • November to February - Northwest Monsoon (Amihan)
• Atmospheric gases


  • Nitrogen
  • Oxygen
  • Water vapor
  • Carbon dioxide
  • Methane
  • Nitrous oxide
  • Ozone