food chains

• What is the main focus of today's video?

  Energy passing through an ecosystem
• What do food chains illustrate in an ecosystem?

  What gets eaten by what
• How does a food chain differ from a food web?

  A food chain shows one interaction chain
• What is the starting point of all food chains?

  A producer
• What is a producer in an ecosystem?

  A photosynthetic organism like grass
• What does the term 'photosynthetic' mean?

  Organisms produce glucose using sunlight
• What do we call the biological molecules produced by plants?

  Biomass
• Who are the primary consumers in a food chain?

  Organisms that eat producers
• Which animal is used as an example of a primary consumer?

  Mice
• What is the role of secondary consumers?

  They feed on primary consumers
• What type of animal is an example of a secondary consumer?

  An owl
• What does 'tertiary' refer to in a food chain?

  The third level of consumers
• What happens to energy as it moves up the food chain?

  Most energy gets lost
• If there are 1,000 joules in grass, how much energy is passed to mice?

  About 100 joules
• How much energy might an owl receive from the food chain?

  About 20 joules
• What do the arrows in a food chain represent?

  The flow of energy
• What is a predator-prey cycle?

  Population variations of predators and prey
• How do predator and prey populations interact over time?

  They cycle up and down together
• What does it mean when predator and prey populations are 'out of phase'?

  Predator population lags behind prey
• What happens to the mouse population when the owl population is low?

  The mouse population increases
• What occurs when there are many mice available for owls?

  The owl population starts to increase
• What happens when the owl population becomes too high?

  The mouse population declines
• Why do populations cycle rather than reach equilibrium?

  It takes time for populations to change
• What is necessary for owls to increase in population?

  Multiple generations of breeding
• What are the main components of a food chain?

  • Producers (e.g., grass)
  • Primary consumers (e.g., mice)
  • Secondary consumers (e.g., owls)
  • Tertiary consumers (if present)
• What are the steps in a predator-prey cycle?

  1. Low predator population allows prey to increase
  2. Increased prey population supports predator growth
  3. High predator population reduces prey numbers
  4. Decline in predator population allows prey to rise again
  5. Cycle repeats continuously
• A food web shows all possible feeding relationships between organisms within an ecosystem.
• Tertiary consumers are carnivores that feed on secondary consumers.
• Secondary consumers are carnivores that eat primary consumers.
• Primary consumers are herbivores that feed directly on producers, such as plants.
• Food chain is the pathway by which energy flows through an ecosystem
• Energy flow diagram shows how much energy is transferred from one trophic level to another.
• Energy flow diagrams show how energy moves from one trophic level to another, as well as losses due to respiration.
• Consumers obtain nutrients by eating other organisms
• Food webs show how energy flows through different trophic levels in an ecosystem.
• Producers make their own food using sunlight or chemicals.
• Food webs show how energy flows through different levels of the food chain, with producers at the bottom and decomposers at the top.
• Each transfer of energy results in some loss due to respiration or other processes.
• Producers make their own food from sunlight or chemicals using photosynthesis or chemosynthesis
• Decomposers break down dead organic matter into simpler substances.