How is energy used differently in chemical and physical changes and difference between the movement of energy and chemicals in ecosystems?
Energy Use and Storage in Biological, Chemical, and Physical Processes:
Biological Processes: Biological systems use energy to maintain their structure, growth, reproduction, and their response to the environment and environmental change. The primary energy source for most ecosystems is sunlight, which is converted into chemical energy through photosynthesis and then received by NADP/NADPH, transported by ATP and finally stored in organic molecules like glucose, starch, cellulose, lignin, fatty acids, .... This energy flows through the food chain, being transferred from one organism to another. Energy is also stored in biological systems as fat and energy-rich molecules, of which some are already cited.
Chemical Processes: Chemical processes involve the making or breaking of chemical bonds, which can either release or absorb energy. Energy is stored in chemical bonds and can be released through reactions like combustion or cellular respiration. For example, the energy stored in a glucose molecule is released when it's broken down to CO2 and H2O.
Physical Processes: Physical processes involve the transfer of energy without a change in the identity of the substances involved. This can include heat transfer, changes in states of matter, or the movement of objects. Energy can be stored in physical systems as potential energy (like a rock at the top of a hill) or kinetic energy (like a moving object).
Difference Between the Fluxes of Energy and Chemicals in Identical Ecosystems:
Energy Flux: Energy flows through ecosystems in a one-way stream, entering as sunlight and leaving as heat. This flow is irreversible, and energy cannot be recycled in ecosystems. The amount of usable energy decreases as it moves up the food chain, with only about 10% being transferred from one trophic level to the next. This is often represented by a pyramid of energy.
Chemical Flux (Nutrient Cycling): Unlike energy, nutrients and other chemicals can be recycled in ecosystems. Plants take up nutrients from the soil, animals eat the plants, and when they die and decompose, the nutrients return to the soil. This cycling can be represented by a circle of movement, like in the nitrogen or carbon cycles. Even in identical ecosystems, the rates and pathways of these fluxes can vary due to differences in environmental conditions, species compositions, and disturbances.
In identical ecosystems, while the overall structure and processes might be similar, the rates of energy flow and nutrient cycling can vary due to factors like:
Time of Day/Season: Both energy flow and nutrient cycling vary throughout the day or across seasons.
Weather Conditions: Temperature, rainfall, etc., can affect both energy flow and chemical fluxes.
Species Interactions: Different species have unique impacts on energy flow and nutrient cycling.
Disturbances: Events like fires, storms or climate change do alter energy flow and chemical fluxes.
These variations highlight the dynamic nature of ecosystems and the importance of understanding their complexities.
Further reading of the ecology work of Eugene Odum is in his book Fundamentals of Ecology (1953).
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