ecology and key ideas

• ecology

  the study of the relationships between organisms and their environment
• ecosystem

  all the biotic factors and abiotic factors in a particular area which make up a self-contained stem which is self supporting in terms of energy flow
• environment

  all the factors in a habitat which affect an organism (biotic or abiotic)
• habitat

  the geographical area occupied by an ecosystem
• species

  a group of potentially interbreeding individuals which do not normally interbreed with other species
• food chain

  a sequence of organisms in an ecosystem in which each is the food of the next organism in the sequence
• food web

  all the interconnected food chains in an ecosystem
• trophic level

  a feeding level in an ecosystem
• producer

  the first organism in a food chain, an autotroph (capable of manufacturing food by photosynthesis)
• primary consumer

  the second organism in a food chain, obtains energy from the producer (herbivore)
• secondary consumer

  obtains energy from the primary consumer (carnivore)
• pyramid of numbers

  a representation of the number of organisms at each trophic level in an ecosystem
• pyramid of biomass

  a representation of the biomass in each trophic level in an ecosystem
• pyramid of energy

  a representation of the energy in each trophic level in an ecosystem
• biotic factors

  the living components of an ecosystem
• abiotic factors

  the non living components of an ecosystem
• eg of abiotic factors

  light, temperature, water
• eg of biotic factors

  plants, animals, bacteria
• how do biotic and abiotic factors influence ecosystem

  in deserts there are fewer animals because there is less water and vegetation
• biodiversity

  a measure of the variation found in the living world
• random sampling

  studying a small part of the habitat and assuming it contains a representative set of species
• pooter

  a small container connected to two tubes. point one tube at bug you want and suck the other end of the straw
• sweep net

  bag shaped net with handle. swing the net through long grass, it will catch the bugs
• pond net

  net used to collect fish and debris from water. swirl it around and it will catch them
• pitfall trap

  the bugs crawl along the soil and fall into the funnel and down into a cup
• tulgren funnel

  pick up pile of dirt and place it on the gauze with a light on top. The bugs will fall through the gauze and collect at the bottom.
• species richness

  the number of different species within an area
• species evenness

  how evenly distributed the species are
• how to use a quadrat

  1. select a suitably sized quatrat

  2. avoid bias by randomising the quadrat locations

  3. take repeat measurements

  4. average out results by finding the mean
• individual

  any one living thing or organism, eg Gill the goldfish
• population

  a group of individuals of a given species that live in a specific geographic area at one time, eg Gill, his family, and other goldfish
• community

  all the populations in a specific area at a given time
• biosphere

  the global sum of all ecosystems
• only... of energy is passed on to the next trophic level

  10%