Energy and Ecosystems Flashcards
(17 cards)
Define the term biomass.
The mass of carbon or dry mass of tissue per given area.
How is light energy in the atmosphere is converted into chemical energy in a plants biomass?
- Plants synthesise organic compounds using light energy and carbon dioxide during photosynthesis.
- Most of the organic compounds produced are used for respiration, and the rest is stored in the plant’s biomass.
How can calorimetry be used to estimate the chemical energy stored in a certain mass of dry tissuee.
- Weight out the tissue.
- Then burn the tissue and calculate the temperature change.
- The temperature change can be used to calculate the chemical energy stored in the dry mass of tissue.
What are producers?
They are photosynthetic organisms that produce their own food using light energy, water and carbon dioxide.
Define gross primary production.
The chemical energy stored in a plant’s biomass in a given area and volume. This is the total energy converted into chemical energy from light energy during photosynthesis.
Define net primary production.
The total energy stored in a plant biomass after respiratory losses has been taken into account.
What is the NPP energy used for?
This is the energy available for a plant’s growth and reproduction. This is also the enrgy available for the next trophic levels.
How can the net production of consumers be calculated?
N = I - (R + F)
What is the net productivity?
The net production of producers or consumers measured as a rate. The biomass in a given area in a given time.
Why is most of the light energy that falls on the primary producers not used for photosynthesis?
Most of the light is reflected as the photosynthetic pigments only absorb certain wavelengths of light. Also, some pass through the leaves and do not hit the chlorophyll.
Why is most of the energy in a plant’s biomass not available to consumers?
- Not all of the plant is eaten.
- Some of the energy gained is lost through faeces or respiration.
How to measure the percentage efficiency of an energy transfer?
The energy that is transferred/ the total energy available x 100
How do certain farming practices increase the efficiency of energy transfers?
Reducing energy loss to other organisms: Insecticides kill insects that feed on and damage crops. This means the plants lose less biomass. Herbicides kill weeds, meaning the plant has less competition for the things it needs for photosynthesis.
Reducing energy loss through respiration: Animals are kept in small pens to reduce their movement and the energy used for muscle contraction. They are also kept in warm places to reduce the energy used for thermoregulation.
What are food chains?
Simple line of energy transfers.
What are food webs?
Diagrams that show all the food chains in an ecosystem.
What are trophic levels?
The stages of the food chain.
What are decomposers?
Organisms that break down dead or decomposing material and allows the nutrients to be recycled.
