Chapter 4- Energy and matter in ecosystems

• Wherever life exists, it depends on a source if energy and a supply of matter
• Ecosystems across the world are linked in networks of energy and nutrient (matter) exchange between living things (biotic components) and their non-living surroundings (abiotic components)
• Matter


  Anything that takes up space and has mass
• Matter consists of atoms and it makes up and maintains complex structures throughout the universe
• Organic substances


  Almost always contain carbon-hydrogen bonds (e.g. table sugar)
• Inorganic substances


  Don't contain carbon-hydrogen bonds (e.g. table salt)
• Earth's matter has been cycling for 4.5 billion years
• In contrast, energy input is required by ecosystems to continue to function
• Energy


  The capacity to cause change, particularly to do work
• Energy can exist in a variety of forms, such as heat, light and chemical, and can be transformed from one form to another
• Energy cannot be created or destroyed, but only converted from one form to another
• Solar energy


  The sun provides most of earth's energy in the form of electromagnetic radiation
• Heat energy


  Warms our planet's surface, and this in turn warms the atmosphere, driving processes such as tides, weather systems and ocean currents
• Biogeochemical cycle


  The pathways of matter through the living components (organisms) and non-living components (soils, rocks, water, atmosphere) of an ecosystem
• Geochemical cycle


  The chemical interactions that exist in crustal and subcrustal reservoirs, such as the deep earth and lithosphere (crust)
• The amount of energy in sunlight depends on the wavelength of the incoming light
• Because the sun emits light in the visible spectrum, infrared radiation and ultraviolet light, the associated energy is very large
• A small percentage of solar energy is captured by plants and transformed into a form that can cycle through an ecosystem
• Photosynthesis


  Plants transform light energy into chemical energy
• Chemical energy stored in plants is transferred to consumers, which then transform it into other forms of energy for storage and use during respiration and movement
• A small proportion of the energy used by ecosystems comes from geothermal energy, which is heat generated from earth's core
• Wai-O-tapu geothermal reserve


  • Home to diverse communities that can tolerate the lack of sunlight, high temperatures, extreme pressures and acidity
• Archaea


  • Use simple inorganic chemical compounds that contain sulfur and iron as their source of energy and matter
• Chemotrophic bacteria


  • Provide energy to support colonies of giant tube worms in the deep-sea trenches of Pacific ocean
• Producers


  Organisms that have evolved the features to manufacture food in the form of organic matter using the energy in sunlight and simple inorganic substances
• Producers begin all food chains, and all other organisms in an ecosystem rely on producers for energy, either directly or indirectly
• Autotrophs


  Producers, meaning 'self-feeders' - they are able to synthesise organic compounds from inorganic raw materials
• Energy is stored in the chemical bonds in the organic compounds and is released when the chemical bonds are broken
• Photosynthesis


  The biochemical process that producers use to transform the energy in sunlight into chemical energy
• Chloroplasts


  Specialised organelles in plant cells that contain the pigment chlorophyll, which enables photosynthesis to occur
• Photosynthesis in green plants makes greatest use of the red and blue wavelengths of light to produce carbohydrates
• Photosynthesis


  Carbon dioxide + water ---> glucose + oxygen
• Heterotrophs


  Living things that cannot synthesise their own organic compounds (food) from inorganic materials
• Heterotrophs depend on autotrophs directly or indirectly for their energy needs and their supply of matter
• Consumers


  Heterotrophs that acquire energy and matter by consuming other organisms
• Biomass


  Total mass of biological matter (living or dead) in a given area, at a time of measurement, that can be used as an energy source
• Productivity


  Percentage of energy entering an ecosystem that is incorporated into biomass
• Primary productivity


  Percentage of energy that is incorporated into biomass by the primary producers in an ecosystem
• Photosynthetic efficiency


  How well a producer converts light energy into carbohydrates during photosynthesis
• Production of organic materials from the glucose made in photosynthesis is greater in some seasons compared with others, and also varies according to latitude and altitude