Energy Flow and Ecosystem Dynamics

Mr. Andersen explains energy flow in ecosystems, focusing on the role of producers and consumers. The sun is the primary energy source, with energy transferred through photosynthesis and chemosynthesis. Productivity is measured as gross or net primary productivity, with energy loss at each trophic level. Ecological pyramids illustrate energy efficiency, showing that only a small percentage of energy moves to higher levels. The video also covers biomass measurement and the role of decomposers in energy flow.

What is the primary source of energy for ecosystems on Earth?

• The Moon

• The Sun

• Ocean Currents

• Volcanic Activity

Which process do plants use to convert sunlight into chemical energy?

• Chemosynthesis

• Photosynthesis

• Respiration

• Fermentation

Which of the following is a chemical used in chemosynthesis?

• Nitrogen

• Oxygen

• Hydrogen Sulfide

• Carbon Dioxide

What is the difference between gross primary productivity and net primary productivity?

• Net is energy lost as heat, gross is energy stored

• Gross is energy lost as heat, net is energy stored

• Gross includes respiration, net does not

• Net includes respiration, gross does not

Which biome is known for having the highest productivity?

• Tundra

• Savanna

• Desert

• Tropical Rainforest

How does seasonal change affect net primary productivity?

• It remains constant throughout the year

• It decreases in summer

• It increases in winter

• It varies with sunlight availability

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

• 90%

• 10%

• 1%

• 50%

In an ecological pyramid, which level contains the most biomass?

• Tertiary Consumers

• Secondary Consumers

• Primary Consumers

• Producers

What role do decomposers play in an ecosystem?

• They store energy

• They recycle nutrients

• They consume producers

• They produce energy

What is the main reason for energy loss at each trophic level?

• Energy is stored for later use

• Energy is lost as heat

• Energy is converted to biomass

• Energy is used for growth