Organisation of an ecosystem

• A population consists of species that occupy the same habitat
• What is the definition of a habitat?

  The place an organism lives
• A community is made up of populations of different species interacting.
• What are the two types of factors in an ecosystem?

  Biotic and abiotic
• Food chains show the feeding relationships of organisms and the flow of energy
• Biomass refers to the total mass of living material.
• What do the arrows in a food chain represent?

  Biomass transfer direction
• A producer is an organism that makes its own food
• Arrange the following components of a food chain in the correct order:

  1️⃣ Producer

  2️⃣ Primary consumer

  3️⃣ Secondary consumer

  4️⃣ Tertiary consumer
• What are primary producers in an ecosystem?

  Photosynthetic organisms
• A primary consumer feeds on producers.
• What is a predator in an ecosystem?

  A consumer that kills prey
• What is prey in an ecosystem?

  An animal eaten by a predator
• Predator and prey populations rise and fall in cycles in a stable community.
• Why are producers the first trophic level in a food chain?

  They produce biomass
• A quadrat is used to measure the abundance and distribution of organisms in an area
• The mean in ecological studies refers to the average number of organisms
• What is a belt transect used for in ecological studies?

  Studying organism distribution
• The arithmetic mean is calculated by summing the number of organisms and dividing by the total number of organisms.
• What does the term "mode" refer to in ecological studies?

  The most populous organism
• What does the term "median" refer to in ecological studies?

  The middle value
• Describe the steps in which materials cycle through an ecosystem:

  1️⃣ Organisms take in elements

  2️⃣ Elements become biomass

  3️⃣ Elements transfer along food chains

  4️⃣ Elements return through excretion or decomposition
• What are three molecules cycled through ecosystems?

  Oxygen, carbon dioxide, water
• Burning fossil fuels releases carbon dioxide into the atmosphere.
• Microorganisms are important for cycling materials through ecosystems because they decompose dead matter
• What are the stages of the water cycle?

  Evaporation, condensation, precipitation, runoff
• Decomposition involves breaking down dead materials into simpler organic matter.
• What are the two types of decomposition based on oxygen availability?

  Aerobic and anaerobic
• What three factors affect the rate of decomposition?

  Oxygen, temperature, water content
• Some decomposers can respire anaerobically
• How does waterlogged soil affect decomposition?

  Decreases rate due to lack of oxygen
• The optimum temperature for decomposition enzymes is 50°C.
• How is the rate of change calculated when considering decay of biological material?

  Change in value / Change in time
• What is compost and how is it used?

  Decayed organic matter used as fertiliser
• What is produced by biogas generators?

  Methane gas
• Environmental conditions such as temperature, soil pH, and light intensity affect the abundance and distribution of organisms.
• Rising global temperatures have been linked to the extinction of frog species.
• How can polluted water affect ecosystems?

  Causes illness in animals
• What is formed when fossil fuels containing impurities are burned?

  Sulfur dioxide
• Carbon monoxide is formed from the incomplete combustion of fossil fuels