Ecosystems and Biogeochemical Cycles

The video explains the necessity of continuous energy supply and material cycling in ecosystems. It covers the carbon, hydrogen, and oxygen cycle through cellular respiration and photosynthesis, the water cycle through processes like transpiration and evaporation, and the nitrogen cycle, highlighting the role of bacteria in converting nitrogen into usable forms for plants.

Why do ecosystems require a continuous supply of energy from outside?

• To maintain biodiversity

• To ensure raw materials are cycled and reused

• To increase the population of species

• To prevent natural disasters

What is the primary process through which plants release oxygen?

• Transpiration

• Cellular respiration

• Evaporation

• Photosynthesis

What is the opposite process of cellular respiration in terms of gas exchange?

• Condensation

• Evaporation

• Transpiration

• Photosynthesis

Which of the following is NOT a part of the water cycle?

• Transpiration

• Evaporation

• Photosynthesis

• Condensation

How does water in the solid state become reusable by organisms?

• Through evaporation

• Through cellular respiration

• By melting back into liquid water

• Via photosynthesis

What form of nitrogen do green plants primarily need?

• Nitrates

• Ammonia

• Nitrites

• Nitrogen gas

How do animals obtain nitrogen?

• Through transpiration

• By consuming plants or other animals

• Through photosynthesis

• By breathing it in

What role do bacteria of decay play in the nitrogen cycle?

• They fix atmospheric nitrogen

• They release nitrogen gas into the atmosphere

• They assist in photosynthesis

• They convert nitrogenous waste into nitrates

Which process involves changing atmospheric nitrogen into a usable form for plants?

• Evaporation

• Nitrogen fixation

• Transpiration

• Photosynthesis

Which cycle is considered the most complicated among the ones discussed?

• Oxygen cycle

• Carbon cycle

• Water cycle

• Nitrogen cycle