ECOSYSTEM

• Ecosystem


  A community of living things that interact with each other and with the physical world
• Ecosystem


  • Can be very small such as a puddle or under a rock
  • Can also be as big as an ocean or a desert
  • The balance of an ecosystem is important, all things must work together to provide a good living environment
• If there is not enough water, plants and animals will die and the ecosystem will not exist
• Producers


  A living thing that can make its own food
• Producers


  • Plants
  • Trees
  • Flowers
• Consumers


  A living thing that gets its food from eating other living things
• Consumers


  • Polar bear eating a fish
  • Bird eating a berry
  • Zebra eating grass
• Decomposers


  A living thing that breaks down other living things to get nutrients and energy
• Decomposers


  • Vultures eat dead animals
  • Worms and beetles eat dead decaying plants
• Food Chain


  Shows what eats what in an ecosystem
• Food Web


  Complex interconnected group of food chains
• In the marine environment, food chains begin with microscopic algae called phytoplankton
• Phytoplankton are eaten by tiny sea animals called zooplankton, which are in turn eaten by small fish, crustaceans, and a variety of other sea animals
• Decomposers


  Act on dead organisms and change these to simple nutrients which plants can use again
• Biomass


  The total mass of organisms in a food chain or a food web
• Not all plants or animals at one level are eaten by organisms at the next level, some parts are not edible
• Much of the energy is lost as heat, only about 10% of biomass and energy are transferred to the next level
• Biomass Pyramid


  Demonstrates the relationship between producers and consumers, a large amount of producers at the base are needed to support only a few consumers at the top
• The largest amount of biomass and energy are at the base of the pyramid, a decrease or loss occurs at each succeeding level
• 10,000 kg of plankton that photosynthesize are needed to support only 1,000 kg of plankton that do not photosynthesize
• 1,000 kg of primary consumers would support only 100 kg of small fish, which in turn would sustain only 10 kg of lapu-lapu, and 10 kg of lapu-lapu would sustain only 1 kg of the biomass of humans
• Due to the loss of biomass at each level, 10,000 kg of plankton at the base of the pyramid would support only 1 kg of humans who are the top consumers
• In the case of the energy pyramid, the energy of the plankton which are producers at the base of the pyramid is also reduced and only 10% moves to the next level, this loss goes on at every level until only 0.01% reaches the top consumers (humans)
• Cycling of Materials in the Ecosystem


  Producers (plants) are eaten by herbivores (plant-eating animals), herbivores are eaten by carnivores (meat-eaters), and carnivores are eaten by top carnivores, eventually the top carnivores die and decay, the carbon in their bodies then becomes part of the soil and taken up by the producers in a long and complex cycle that reuses this carbon
• Oxygen-Carbon Dioxide Cycle


  Organisms use and produce gases in photosynthesis and respiration, these gases flow through organisms and the environment in a cyclic process
• Water Cycle


  Water vapor in the atmosphere condenses and falls to the Earth's surface as rain, some seeps into the soil and becomes part of the ground water, the remaining water reenters the atmosphere by evaporation
• Nitrogen Cycle


  Nitrogen-fixing bacteria convert nitrogen into ammonia, nitrogen-fixing bacteria live in the soil and are also found within swellings, or nodules in most leguminous plants
• Organisms need nitrogen to build proteins and nucleic acids
• The atmosphere is 79% nitrogen gas (N2), but most organisms are unable to use it in this form
• Nitrogen Fixation


  The process of combining nitrogen with hydrogen to form ammonia
• Monoculture


  Vast tracts of land are converted to single crop farms, this requires large amounts of chemical fertilizers, continuous and uncontrolled use may increase soil acidity and destroy soil structure
• Herbicides and Insecticides


  Farmers spray their crops to kill pests and weeds, but the chemicals also destroy other organisms, including beneficial insects and soil organisms which help in decay