ecosystem nonsense

• what is an ecosystem?

  Any group of living, and non living things, and the interrelationships between them.
• what is a habitat?

  The place where an organism lives
• What is a population?

  All of the organisms of a singular species who live in the same place, at the same time and have the ability to breed together
• What is a community?

  All the populations of different species who live in the same place at the same time and who interact with each other
• what is a niche?

  A specific ecological role or position occupied by an organism within an ecosystem.
• how do producers create energy?

  They use photosynthesis to supply chemical energy to themselves and subsequent organisms
• What type of organisms are primary consumers?

  They are herbivores, eating the producer
• What type of organisms are tertiary and secondary consumers?


  They are carnivorous
• What do decomposers feed on?

  Dead organisms or waste materials
• what are abiotic factors?

  Abiotic factors describe the impact that non living components of an ecosystem have.
• What are examples of a biotic factors?

  pH

  Relative humidity

  Pollutants

  temperature

  Salt content of water and soil
• why are ecosystems described as dynamic?

  Ecosystems change
• what is meant by carrying capacity?

  The maximum population size that an environment can sustain.
• what is meant by the 10% rule?

  10 % of energy is transferred between trophic levels due to respiration and excretion
• how is the efficiency of biomass transfers between trophic levels be calculated?

  Efficiency = biomass transferred / biomass intake x 100
• Give examples of how humans manipulate the transfer of biomass through ecosystems by reducing the energy lost?

  Restricting the movement of animals

  Providing animals with higher energy food

  Keeping animals indoors to reduce the energy transferred as heat

  Removing competition and predators
• why cant plants and animals not obtain nitrogen via gas exchange?

  nitrogen (N 2 ) has a triple bond
• How do plants and animals absorb nitrogen containing substances?

  Microorganisms are needed to convern nitrogen gas into nitrogen containing substances
• what are the key processes in the nitrogen cycle?

  Ammonification, Nitrification, Nitrogen fixing, denitrification
• what is succession?

  The change in an ecological community over time
• what is a pioneer species?

  A pioneer species is the first organism to colonize a barren or disturbed area.
• What does primary succession always start with?

  A pioneer species colonising bare rock or sand
• Pioneer species, like lichen, are adapted to survive in harsh abiotic factors. Through their death, and decomposition, abiotic factors become less harsh and form a thin layer of soil called humus #
• what happens when pioneer species die ?

  Mosses and smaller plants are able to survive- they increase the depth and nutrient content of soil. The pattern continues, and as the abiotic factors continue to be less harsh, larger plants can survive and change the environment further
• in primary succession, why is each existing species out competed by a new one colonising?

  Each new species may change the environment in such a way that it becomes less suitable for the previous species
• what is the final stage in a succession?

  The climax community, dominated by trees
• what is a secondary succession, and what happens?

  A secondary succession is when the succession is disrupted and plants are destroyed. The succession starts again, but the soil is already crusted, so it doesnt start from the bare rock seral stage
• what is deflected succession?

  When human activities prevent the progress of succession, a climax community wont be reached fi there are animals grazing or the area is trampled by humans
• what is interspecific competition?

  Competition between different species for resources.
• what is intraspecific competition?

  When members of the same species are in competition for resources and a mate. The competition for a mate links to the courtship rituals.
• the interaction between predators and prey in a wood web is represented in a predator prey graph.
• What are the same patterns followed in a predator prey graph?

  The size of t he predator and prey populations will fluctuate

  There will be more prey than predators

  The size of the prey population will change before the predator population
• what is net primary productivity?

  The rate at which ewnergy is transferred into the organic molecules that make up new plant biomass, that is the chemical energy store in plant biomass after respiratory losses to the environment have been taken into account
• What is gross primary productivity?

  the rate at which energy is incorporated into organic molecule in the plants in photosynthesis, that is the chemical energy store in plant biomass, in a given area or volume, in a given time
• describe the nitrogen cycle?

  Nitrogen is first fixed by bacteria, which live in the root nodules of leguminous plants. In anaerobic conditions, which are maintained with the use of special oxygen absorbing proteins, these enable nitrogen reductase to reduce the nitrogen gas to ammonium ions. The NH4+ ions are released by bacteria in the putrefaction of proteins of dead matter. Chemotrophic bacteria oxidise NH4+ ions to nitrites. Nitrobacter subsequently oxidises nitrites to nitrates in the presence of oxygen. Plants absorb the nitrates.
• what are the three methods of sampling?

  Line transects

  Quadrats

  Belt transects
• Describe the use of a line transect?

  Where a line is placed down across the habitat and species in contact with the line are recorded
• Describe the use of a quadrat?

  A square frame of a given size is randomly placed in the area being sampled, species inside of the quadrat are identified and counted to determine the abdundance.
• Describe the use of a belt transect?

  2 tape measures are laid out and samples are taken between the two at set intervals along the tapes.
• what is meant by coppicing?

  The cutting down of trees close to the ground to encourage new growth- effective because stumps have good root systems.