Ecosystems and biosphere

• Ecosystem


  All the living organisms in a given area as well as the abiotic factors with which they interact
• All organisms living on Earth need to carry out life processes such as growth, movement, and reproduction
• The ultimate source of energy for an ecosystem is the Sun
• The sun's energy is converted from one form to another and passed through the various levels of the ecosystem
• The flow of energy through an ecosystem is crucial to the ecosystem's ability to sustain life
• Initial working hypothesis for how plants gained mass

  Plants grow by eating soil through their roots
• Van Helmont's experiment


  Planted willow tree and soil only decreased by 2 ounces but the tree grew lots
• Matter


  Physical substances that have mass and occupy space (volume)
• Energy


  The ability to do work
• Atom


  The basic building blocks of matter, the smallest particle that still exhibits the characteristics of its element
• Each element represents a different kind of atom
• Joseph Priestley's hypothesis


  Air was not a single "elementary substance", but a "composition"
• Priestley's experiments with "injured air"

  The candle placed in the "injured air" would extinguish very quickly
• Priestley had discovered oxygen
• Proton


  Positively charged, located in the nucleus
• Electron


  Negatively charged, orbits the nucleus
• Neutron


  Neutral, located in the nucleus
• Chemical bond


  When atoms form chemical bonds with each other, they make molecules
• Molecules found in air & gases

  • Nitrogen
  • Oxygen
  • Water
  • Carbon dioxide
• Jan Ingenhouse's experiment with plants

  He put plants in a closed glass jar, one in sun and one in shade. Only the sunlight one grew because sun is needed in photosynthesis
• Electromagnetic spectrum


  Radio, Microwave, Infrared, Visible, Ultraviolet, X-Ray, Gamma Ray
• Visible light


  • The range of wavelengths we can detect with our eyes
• Sunlight


  The main energy source for life on Earth
• Without energy from the sun, life on Earth could not exist
• Of all the sun's energy that reaches the Earth, less than 1% is actually used by living organisms
• This 1% is used by the organisms that are capable of photosynthesis
• Photosynthesis


  The process by which green plants use the light energy from the sun to convert water and carbon dioxide into glucose and oxygen
• Plants can only use certain wavelengths of visible light for photosynthesis (not green)
• Nicholas de Sassure's experiment

  Grew plants in sealed containers of carbon dioxide and measured the mass afterwards. Concluded that the increased mass was a combination of water from the soil and carbon from the air.
• Chemical equation for photosynthesis

  6 H2O + 6 CO2 + solar energy → C6H12O6 + 6 O2
• Organisms that cannot carry out photosynthesis rely on energy stored in glucose
• Photosynthesis provides food and removes carbon dioxide while releasing oxygen into the atmosphere
• Autotrophs


  Organisms that have the ability to use energy from the sun to convert simple inorganic substances into complex organic compounds
• Autotrophs


  • Green plants, algae, protists, some bacteria
• Photosynthetic bacteria (cyanobacteria) are also important oxygen producers
• Chemoautotrophs


  Organisms that can produce food through a process called chemosynthesis, using the energy contained in the chemical bonds of inorganic molecules such as hydrogen sulfide
• Chemosynthesis


  A process that is carried out by several types of bacteria to convert inorganic compounds into viable energy
• Cellular respiration


  C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy
• Photosynthesis and respiration form the basis of the flow of energy and the cycling of matter that make up living ecosystems
• First Law of Thermodynamics

  Energy cannot be created or destroyed, only changed in form