Organisation of an Ecosystem

• Define Population

  A species that occupt the same habitat.  
• Define community.

  Populations of different species interacting. 
• Define ecosystem.


  Interactions between abiotic and biotic factors in an area. 
• What do food chains show?  

  Food chains show the feeding relationships of different organisms and the flow of energy between the organisms.  
• Define biomass.

  The total mass of living material.
• What are trophic levels?

  The stages in a food chain.  
• What do arrows in a food chain represent?

  The direction of biomass transfer.
• Describe a simple food chain.

  Producer → Primary Consumer → Secondary Consumer → Tertiary Consumer
• What is a producer?

  An organism that makes its own food.
• What type of organisms are primary producers?

  Photosynthetic organisms like green plants and algae that trap energy from the sun. 
• What is a primary consumer?

  An organism that feeds on producers.
• What is a secondary consumer? 

  An organism that feeds on primary consumers.
• What is a tertiary consumer?

  An organism that feeds on a secondary consumer. 
• What is a predator?

  A consumer that kills and eats other animals. 
• What is prey?

  An animal that is killed or eaten by another animal.
• Describe the pattern of predators and prey in a stable community.

  The numbers of predators and prey rise and fall in cycles.
• What are producers the first trophic level?

  Producers provide all biomass for the food chain (production of glucose via photosynthesis)

  The rest of the food chain involves the transfers of this biomass.
• What piece of apparatus is used to measure the abundance and distrubtion of organisms in an area.

  Quadrat.
• What piece of apparatus is used to study the distrubtion of organisms across a gradient? 

  Belt transect.
• Describe how materials cycle through the living and non-living components of an ecosystem?

  Organisms take in elements from their surroundings e.g. soil, air

  Elements converted into complex compounds which becomes biomass.

  Elements transferred along food chains.

  Elements returned to environment during excretion and decomposition of dead organisms.  
• Give 3 molecules which are cycled through ecosystems?

  Oxygen

  Carbon dioxide

  Water
• Describe the carbon cycle

  Plants fix carbon dioxide into organic molecules during photosynthesis

  The organic carbon-containing molecules are passed onto organisms that eat plants

  Carbon dioxide is released from animals and plants through respiration

  Burning fossil fuels also releases carbon dioxide into the atmosphere. 
• Why is the carbon cycle important?

  Carbon-containing molecules such as glucose are important for living organisms to grow and provide energy for vital functions within cells.
• Describe the water cycle.

  -Water from lakes and oceans evaporate

  -Evaporated water condenses into clouds and returns as precipitation

  -Water from precipitation is useful for life on land

  -Water returns to rivers and oceans through surface runoff. 
• Why is the water cycle important?

  Living organisms require water and the water cycle provides organisms on land with a continuous supply of water. 
• Why are microorganisms important for the cycling of materials through an ecosystem?

  Microorganisms (bacteria and fungi) return carbon to the environment by releasing carbon dioxide through respiration while they decompose dead matter. The decomposition of dead matter in soil returns mineral ions to the environment for other organisms to use e.g. plants use mineral ions for growth. 
• How can different temperatures be bad for certain communities?

  -If the temperature is too low, growth will be slower as organisms will use more energy to stay warm

  -If temperature is too high, organisms can die and water will become limited as evaporation increases
• How can changes in water levels affect ecosystems? (higher)

  Animals may have to migrate to find water

  Melting ice caps may destory the habitats of animals (rising sea levels or icy conditions) 
• How can atmospheric gases affect ecosystems? (Higher)

  -Some organisms cannot survive when certain gases are present

  -Polluted water can cause illness to animals that drink it
• What detrimental impacts can sulfur dioxide have on the environment? 

  -Formed when fossil fuels containing impurities are burnt

  -Sulfur dioxide can dissolve in water to form acid rain which can corrode builidings and pollute water sources. 
• What detrimental impacts can carbon monoxide have on the environment?

  -Carbon monoxide is formed through the incomplete combustion of fossil fuels

  -Carbon monoxide binds irreversibly to haemoglobin which prevents oxygen from binding to haemoglobin

  -Too much exposure can cause unconsciousness and death.
• Name 5 Greenhouse Gases

  Water Vapour

  Carbon Dioxide

  Nitrous Oxide

  Methane

  CFCs
• Give 3 human activites that contribute to greenhouse gases

  -Burning fossil fuels

  -Deforestation

  -Large scale livestock farming
• How do greenhouse gases lead to global warming?

  Greenhouse gases allow heat from the sun to enter the atmosphere

  The gases act as a 'blanket' and trap heat in the atmosphere 
• State 3 negative consequences of global warming.  

  Sea level rise by melting icebergs

  Disrupted farming and agriculture

  Increased spread of diseases in warmer countries.