Ecosystem Dynamics and Nutrient Cycles

This lecture covers the cycles of matter and energy flow in ecosystems. It reviews the water, carbon, nitrogen, and phosphorus cycles, explaining their processes and significance. The lecture also discusses energy flow through ecological pyramids, emphasizing the rule of 10% energy transfer between trophic levels. Key concepts include the interconnectedness of energy and matter, the role of decomposers, and the impact of human activities on these cycles.

What is the main difference between the flow of energy and the flow of matter in ecosystems?

• Both energy and matter flow in one direction.

• Both energy and matter flow cyclically.

• Energy flows in one direction, while matter flows cyclically.

• Energy flows cyclically, while matter flows in one direction.

Which of the following is NOT a reservoir in the water cycle?

• Hydrosphere

• Lithosphere

• Biosphere

• Atmosphere

What process allows plants to release water vapor into the atmosphere?

• Precipitation

• Transpiration

• Condensation

• Evaporation

Which gas is primarily responsible for ocean acidification?

• Nitrogen

• Oxygen

• Carbon Dioxide

• Methane

What is the primary human activity that increases atmospheric carbon dioxide levels?

• Burning of fossil fuels

• Industrial waste

• Deforestation

• Agriculture

What natural phenomenon converts atmospheric nitrogen into a usable form?

• Lightning

• Earthquakes

• Photosynthesis

• Volcanic eruptions

Which nutrient is crucial for the formation of DNA?

• Nitrogen

• Oxygen

• Carbon

• Phosphorus

In a food web, what role do decomposers play?

• They are at the top of the food chain.

• They break down dead materials for primary producers.

• They produce energy for primary consumers.

• They consume primary producers.

What percentage of energy is typically transferred from one trophic level to the next?

• 50%

• 20%

• 10%

• 5%

Which of the following best describes a food web?

• A linear sequence of organisms where energy is transferred.

• A single path of energy flow in an ecosystem.

• A network of feeding interactions among organisms.

• A diagram showing only producers and consumers.