Question

1. think about the flow of matter and energy in a pyramid model with a producer level, a primary consumer level, a secondary consumer level, and a tertiary consumer level. select all correct answers.

a) the sun is the ultimate source of energy in an ecosystem.
b) matter flows and is often conserved within or among ecosystems.
c) energy flows through ecosystems, but only a certain amount of energy is transformed into biomass.
d) energy flows through ecosystems, but some is lost to the environment as heat.
e) matter and energy are completely conserved and transformed into biomass within an ecosystem.

Explanation:

• Option A: Producers (like plants) use sunlight (from the sun) to make food via photosynthesis. So, the sun is the ultimate energy source for the ecosystem.
• Option B: Matter (e.g., carbon, nitrogen) is recycled in ecosystems (e.g., carbon cycle). It flows and is conserved (as per the law of conservation of mass).
• Option C: Energy flows through trophic levels. Only about 10% of energy is transferred as biomass from one level to the next (e.g., from producers to primary consumers).
• Option D: Energy is lost as heat at each trophic level (due to metabolic processes like respiration).
• Option E: Energy is not completely conserved as biomass. As mentioned in option D, energy is lost as heat. Matter is conserved (as in option B), but not all matter is transformed into biomass (e.g., some is excreted as waste).

Answer:

A. The sun is the ultimate source of energy in an ecosystem, B. Matter flows and is often conserved within or among ecosystems, C. Energy flows through ecosystems, but only a certain amount of energy is transformed into biomass, D. Energy flows through ecosystems, but some is lost to the environment as heat.