Nutrient Cycles

matter flows from one trophic level to another, and elements are recycled within and among ecosystems

• carbon cycle

• biogeochemical cycle

• nitrogen cycle

• phosphorus cycle

bacteria obtain energy by converting nitrates into nitrogen gas that is released into the atmosphere

• nitrogen fixation

• denitrification

• greenhouse gases

• nitrogen cycle

What are the four most important materials needed by living organisms?

• water, carbon, oxygen, nitrogen
• water, food, oxygen, carbon
• water, carbon, nitrogen, phosphorous
• water, carbon, food, phosphorous

This is essential to living organisms, it is found in nucleic acid and amino acids.

• Nitrogen
• Carbon
• Water
• Phosphorous

What is it called when water vapor cools and changes into a liquid?

• condensation
• respiration
• precipitation
• evaporation

Which of the following is NOT a stage of the nitrogen cycle?

• organisms breathe in nitrogen gas
• organisms release nitrogen compounds via waste or decomposition
• bacteria convert unusable nitrogen to usable nitrogen
• plants absorb nitrogen compounds from the soil

Which of these is the greatest cause of harmful levels of carbon in the atmosphere?

• respiration
• combustion
• photosynthesis
• decomposition

Which of these steps is part of the nitrogen cycle AND the phosphorous cycle?

• it starts off inside underwater rocks and dirt
• bacteria convert it into organic compounds
• animals leaving waste and death and decay release it back into the soil
• rain water and ocean waves break off pieces, putting it back into the ecosystem

Which of these is a step in the carbon cycle, the nitrogen cycle, and the phosphorous cycle?

• condensation
• decomposition
• respiration
• photosynthesis

This process removes carbon from the atmosphere?

• combustion

• cellular respiration

• photosynthesis

• decomposition