Ecosystem Components and Energy Flow

This lecture explores energy flow in ecosystems, starting with the definition of ecosystems, which include both biotic and abiotic factors. It explains how sunlight is the primary energy source, converted by producers through photosynthesis into glucose. Consumers, including herbivores, carnivores, and omnivores, use this energy through cellular respiration. The lecture details trophic levels and energy pyramids, highlighting the inefficiency of energy transfer. It distinguishes between food chains and webs, emphasizing the complexity of ecosystems. Finally, it covers productivity, measuring energy availability in ecosystems, and the impact of human activities.

What are the two main components of an ecosystem?

• Sunlight and water

• Plants and animals

• Biotic and abiotic factors

• Producers and consumers

Which process allows producers to convert sunlight into usable energy?

• Fermentation

• Cellular respiration

• Photosynthesis

• Decomposition

What is the primary role of consumers in an ecosystem?

• To consume producers and other consumers

• To produce energy

• To decompose organic matter

• To convert sunlight into glucose

Which of the following is a primary consumer?

• Grass

• Mouse

• Snake

• Hawk

Why do energy levels decrease as you move up the energy pyramid?

• Energy is lost as heat

• Producers consume more energy

• Energy is converted into matter

• Consumers store all the energy

What is the main difference between a food chain and a food web?

• A food chain is more complex

• A food web shows multiple energy paths

• A food web is linear

• A food chain includes decomposers

What does gross primary productivity measure?

• Energy available to decomposers

• Total energy captured by plants

• Total energy used by consumers

• Energy lost as heat

How is net primary productivity calculated?

• Total energy captured by decomposers

• Energy available to producers

• GPP minus energy used by plants

• GPP minus energy used by consumers

What percentage of Earth's net primary productivity is used by humans?

• 12%

• 50%

• 28%

• 40%

Why might eliminating meat from our diet help feed more people?

• It decreases the number of trophic levels

• It reduces energy loss in the food chain

• It enhances photosynthesis

• It increases gross primary productivity