In one or two sentences, explain how the chemical equation for cellular respiration shows that plants cycle matter. Include the numbers of molecules and atoms involved to support your explanation.(2 points)
The chemical equation for cellular respiration (C6H12O6 + 6O2 -> 6CO2 + 6H2O) shows that plants cycle matter by taking in 1 molecule of glucose (C6H12O6) and 6 molecules of oxygen (O2), and producing 6 molecules of carbon dioxide (CO2) and 6 molecules of water (H2O), thereby converting and recycling the atoms involved in the process.
In a food pyramid, there is typically less biomass at the top (i.e., there are very few individual tertiary consumers, whereas there are numerous individual producers). In three to five sentences, explain this phenomenon, citing evidence relating to energy flow and how plants support ecosystems.(4 points)
The phenomenon of less biomass at the top of a food pyramid can be explained by the principles of energy flow and the role of plants in supporting ecosystems. Plants, as primary producers, convert energy from the sun into chemical energy through photosynthesis. This energy is then transferred to herbivores, primary consumers, who consume the plants. However, as energy is transferred from one trophic level to the next, there is a loss of energy in each transfer, resulting in less total energy being available to the next level.
This energy loss occurs due to cellular respiration, metabolic inefficiencies, and heat production. Consequently, there is not enough energy available to sustain a large population of tertiary consumers, resulting in a smaller biomass. Additionally, plants, being the primary producers, provide the foundation for the entire ecosystem, serving as the primary source of nutrients and energy.
Evidence supporting this phenomenon includes biomagnification studies that show the concentration of certain pollutants increasing as you move up the food chain, indicating a decrease in biomass at higher trophic levels. Ecological studies show that ecosystems with a greater density and diversity of plant species tend to have higher overall biomass, highlighting the importance of plants in supporting ecosystems and the subsequent decrease in biomass at higher trophic levels.