B2.2 photosynthesis and thermodynamics and productivity Flashcards
word equation for photosynthesis
carbon dioxide + water –> glucose + oxygen
word equation for aerobic resipration
glucose + oxygen –> carbon dioxide + water
autotrophs
organisms that produce their own energy.
heterophs
an organism that cannot produce its own food. primary, secondary or tertiary consumer
What sustains ecosystems?
Ecosystems are sustained by supplies of energy and matter, as they are open systems in which energy and matter are exchanged.
What does the first law of thermodynamics state about energy in ecosystems?
The first law of thermodynamics states that energy can be transformed from one form to another but cannot be created or destroyed as it flows through ecosystems.
What are examples of energy transformations in ecosystems?
Energy transformations include light energy converting to chemical energy and chemical energy converting to heat.
What is the role of photosynthesis and cellular respiration in ecosystems?
Photosynthesis and cellular respiration transform energy and matter in ecosystems through chemical reactions and energy transformations.
What is photosynthesis, and what does it produce?
Photosynthesis is the conversion of light energy into chemical energy in the form of glucose, which can be stored as biomass by autotrophs.
What are producers, and what role do they play in a food chain?
Producers, such as plants, algae, and photosynthetic bacteria, form the first trophic level in a food chain by producing their own food using photosynthesis.
What does cellular respiration do?
Cellular respiration releases energy from glucose, converting it into a chemical form that can easily be used for active processes in living cells.
Why is heat generated during cellular respiration?
Heat is generated because cellular respiration is not 100% efficient at transferring energy from substrates like carbohydrates into usable chemical energy.
What does the second law of thermodynamics state about energy transformations?
The second law of thermodynamics states that energy transformations are inefficient, with some energy always degraded into a less useful form, like heat.
Why are energy transfers in ecosystems never 100% efficient?
Energy transfers are never 100% efficient because of energy losses, particularly during cellular respiration, as explained by the second law of thermodynamics.
Gross productivity (GP)
the total gain in biomass by an organism.
Net productivity (NP)
the amount remaining after losses due to cellular respiration.
Why are energy losses due to cellular respiration greater in consumers than in producers?
Energy losses due to cellular respiration are greater in consumers because they engage in more energy-requiring activities.
What does the net productivity (NP) of an organism or trophic level represent?
The NP of an organism or trophic level represents the maximum sustainable yield that can be harvested without reducing future availability.
What is the method for assessing the productivity of an ecosystem?
- Take samples of biomass in a quadrat.
- Dry it
- Weigh it (biomass)
- Use a calorimeter (a device for measuring the heat developed during a mechanical, electrical, or chemical reaction
and for calculating the heat capacity of materials). to calculate energy. (Joules) - Multiply up from quadrat to sample area size.
Gross Primary Productivity GPP
the total amount of biomass produced by photosynthesis in an ecosystem.
Net Primary Productivity NPP
the total amount of biomass stored and available for harvesting.
how to calculate NPP
GPP - Respiration
how much energy is passed on to the next trophic level
10%
What is a maximum sustainable yield (MSY)?
The maximum sustainable yield is the largest amount of organisms that can be removed from a trophic level without reducing the availability of resources or energy for the future.
Why is assessing net productivity (NP) important for sustainable use of natural capital?
it ensures that only the maximum sustainable yield is taken, allowing the ecosystem to replace any loss and maintain energy availability for the future.
