environment and biodiversity

• Pyramids of biomass

  • Show the biomass of each trophic level in a food chain
  • Bars get smaller as you go up the trophic levels indicating decreasing total mass of organisms in each level
• Biomass transfer in a food chain

  1. Most of the biomass and energy is lost or used when one organism is consumed by another

  2. About 10% of biomass actually gets transferred up to the next level
• Efficiency of biomass transfer can be calculated as the percentage of biomass passed on each time
• Reasons for only 10% biomass and energy transfer

  • Organisms don't eat every part of the consumed organism
  • Not all parts eaten are absorbed and some are excreted
  • Most nutrients absorbed are used for energy release through respiration rather than growth
• Calculation of efficiency of biomass transfer

  1. Efficiency = (Biomass transferred to the next level / Biomass available at the previous level) * 100

  2. Example: Efficiency between snakes and rabbits = 15 kilos / 144 kilos * 100 = 10.4%
• The term biomass means the mass of living organisms
• indicator species are organisms whose presence or absence provides information on the environment
• lichen are 2 fungi and an algae in a symbiotic relationship, they are sensitive to air pollution
• bushy lichen - really clean air

  leafy lichen - survive on small amounts of air pollution

  crusty lichen - survive in more polluted areas
• mutualism - both organisms benefit
• commensalism - one organism benefits and the other is not harmed
• parasitism - one organism benefits at the expense of another
• community

  All the different organisms living and interacting with one another in a particular area
• food web

  A diagram of Interlinked food chains. It shows how the feeding relationships in a community are interdependent
• biomass

  Mass of tissues in an organism
• trophic level

  Feeding level in a food chain, such as producer or primary consumer
• sample

  A small portion of an area or population
• pyramid of biomass

  Diagram showing the amount of biomass at different trophic levels of a food chain
• Interdependent

  When organisms in an area need each other for resources, e.g., for food and shelter
• quadrat

  A square frame of known area, such as 1 m², that is placed on the ground to get a sample of the organisms living in a small area
• biodiversity

  The variety of species in an area
• pollutant

  A substance that harms living organisms when released into the environment
• distribution

  The places in which a certain organism can be found in an area
• compete

  When organisms interact to get a limited resource that they need
• predation

  When one animal species kills and eats another animal species
• invertebrate

  An animal without a backbone
• blackspot fungus

  A type of fungus that causes black spots on plants
• habitat

  The place in which an organism lives, e.g., woodland or seashore
• population

  A group of one species living in the same area
• resources

  Something that an organism needs to stay alive such as food, water, and space
• abundance

  A measure of how common something is
• ecosystem

  An area in which all the living organisms and all the non-living physical factors in an area form a stable relationship that needs no input from outside the area to remain stable
• belt transect

  A line in an environment along which samples are taken to measure the effect of an abiotic factor on the distribution of organisms
• biotic (factor)

  Factors caused by living organisms in an environment, such as competition or predation
• adaptation

  The features of an organism that enable it to do a certain function (job)
• Sankey diagram

  A diagram showing energy transfers, where the width of each arrow is proportional to the amount of energy the arrow represents
• abiotic factors

  Non-living conditions that can influence where plants or animals live (e.g., temperature, the amount of light)
• biotic factors

  Living components (the organisms) in an ecosystem
• pollution

  Harm caused to the environment, such as by adding poisonous substances or by abnormally high amounts of a substance
• competition

  When organisms need the same resources as each other, they struggle against each other to get those resources. We say that they 'compete for those things'