52 Energy and Matter in Ecoystems

In the ecological pyramid, the amount of potential food for each tropic level

• remains the same
• increases over time
• increases from top to bottom
• increases from bottom to top

The animals in the food web release ______ into the environment, which plants use for _____.

• oxygen;  respiration
• carbon dioxide;  photosynthesis
• carbon dioxide;  respiration
• water vapor; photosynthesis

Which of these statements about a food web is true?

• Matter is changed into various forms but the total quantity remains unchanged.
• Matter is created at the start of a food web and destroyed in the end.
• There are an equal number of producers and consumers.
• The quantity of matter decreases as the food web progresses from producer to consumer.

What happens to any matter that is not used by consumers in a food chain?

• It remains unconsumed forever.
• It is stored by all consumers for use in the future.
• It iis recycled by producers and brought back into the food chain later.
• It is decomposed by decomposers and brought back into the food web for later use.

What is energy?

• anything that takes up space
• anything that has mass
• the ability to do work
• anything that has density

What type of organism would be in section C of the pyramid?

• autotrophs
• carnivores
• herbivores
• producers

What type of organisms would be in section B of the pyramid?

• autotrophs
• carnivores
• herbivores
• producers

What type of organism would be in section A of the pyramid?

• heterotrophs
• carnivores
• herbivores
• producers

Which of the following statements about energy pyramids is true?

• The largest proportion of organisms are found in the top level.
• The smallest proportion of organisms are found in the top level.
• Carnivores are most likely to be found in the bottom level.
• Producers are most likely to be found in the top level.

What is happening at X?

• Bacteria break down molecules in animals in carbon-based soil nutrients.
• Animals are decomposing and releasing carbon into the soil.
• Animals are converting carbon dioxide from the atmosphere to oxygen.
• Animals are breaking down organic molecules and releasing carbon dioxide into the atmosphere.