7.2-organisation of an ecosystem

• What is a population?

  A species that occupy the same habitat
• What is a community?

  Populations of different species interacting
• What is a habitat?

  The place in which an organism lives
• What is an ecosystem?

  The interactions between biotic and abiotic factors
• What do food chains show?

  The feeding relationships and energy flow between organisms
• What are trophic levels?

  The stages in a food chain
• What is biomass?

  The total mass of living material
• 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 types of organisms are primary producers?

  Photosynthetic organisms like green plants and algae
• What is a secondary consumer?

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

  An organism that feeds on producers
• What is a producer?

  An organism that makes its own food
• What is a tertiary consumer?

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

  A consumer that kills and eats other animals
• Describe the pattern of predators and prey in a stable community.

  The numbers of predators and prey rise and fall in cycles
• What is prey?

  An animal that is killed and eaten by another animal
• Why are producers the first trophic level?

  They provide all biomass for the food chain
• What piece of apparatus is used to measure the abundance and distribution of organisms in an area?

  Quadrat
• What is meant by the term “mean” in abundance studies?

  The average number of organisms
• What piece of apparatus is used to study the distribution of organisms across a gradient?

  Belt transect
• How is the arithmetic mean calculated?

  Sum of each organism / total number of each type
• What is meant by the term “mode” in abundance studies?

  The most populous organism
• Describe how materials cycle through the living and non-living components of an ecosystem.

  • Organisms take in elements from surroundings
  • Elements converted to complex molecules (biomass)
  • Elements transferred along food chains
  • Elements returned during excretion and decomposition
• What is meant by the term “median” in abundance studies?

  The middle value when arranged from lowest to highest
• Give 3 molecules which are cycled through ecosystems.

  Oxygen, carbon dioxide, and water
• Describe the carbon cycle.

  • Plants fix carbon dioxide during photosynthesis
  • Organic molecules passed to organisms that eat plants
  • Carbon dioxide released by respiration
  • Burning fossil fuels releases carbon dioxide
• Describe the water cycle.

  • Water evaporates from lakes and oceans
  • Evaporated water condenses into clouds
  • Returns as precipitation
  • Water returns to rivers and oceans through runoff
• Why is the carbon cycle important?

  Carbon-containing molecules are vital for growth
• Why is the water cycle important?

  It provides a continuous supply of water
• Why are microorganisms important for the cycling of materials?

  They return carbon by decomposing dead matter
• Describe how environmental conditions affect communities.

  • Conditions like temperature and soil pH affect abundance
  • Rising temperatures linked to frog species extinction
• How can different temperatures be bad for certain communities?

  Low temperatures slow growth; high can cause death
• How can atmospheric gases affect ecosystems?

  Some organisms cannot survive certain gases
• How can changes in water levels affect ecosystems?

  Animals may migrate to find water
• What detrimental impacts can sulfur dioxide have on the environment?

  It forms acid rain that erodes buildings
• What detrimental impacts can carbon monoxide have on the environment?

  It binds to hemoglobin, preventing oxygen transport
• Give 3 human activities that contribute to greenhouse gases.

  • Burning fossil fuels
  • Deforestation
  • Large scale livestock farming
• Name 5 greenhouse gases.

  • Water vapour
  • Carbon dioxide
  • Nitrous oxide
  • Methane
  • CFCs
• How do greenhouse gases lead to global warming?

  They trap heat in the atmosphere