Ecology and the Ecosystem Flashcards
What is a producer in the food chain?
Organism that uses chlorophyll to absorb light energy, carry out photosynthesis in presence of water and carbon dioxide to convert light energy to chemical energy in the form of glucose.
What is a consumer?
Consumers need to feed on other organisms to obtain energy in the form of organic molecules.
What is a trophic level?
Each stage in a food chain is a trophic level, where a trophic level is the feeding position of an organism in a food chain.
Why are most food chains short?
A large amount of energy is lost at each trophic level (~90%). Thus less and less energy is available at each trophic level. Short food chains are more efficient then long food chains.
Describe the Carbon Cycle.
The carbon in a glucose molecule in the body of an animal can be passed from one organism to another through feeding in the food chain. Some glucose will be oxidised to release energy during respiration and carbon is released to the atmosphere as carbon dioxide. When organisms like decomposers break down dead organic matter, carbon is released to the air as CO2.
CO2 in the atm is taken by producers, which use the CO2 and H2O for the synthesis of glucose in presence of light absorbed by chlorophyll. The carbon in the glucose is cycled in the food chain when this organism is consumed by another organism.
What is a carbon sink?
A carbon sink is an area that stores carbon compounds for an indefinite time. It stores more carbon than it releases.
What is a carbon sink?
A carbon sink is an area that stores carbon compounds for an indefinite time. It stores more carbon than it releases.
What is eutrophication?
Eutrophication is the process by which water receives excess nutrients like phosphates or nitrates (from sewage or fertilisers) , which cause an excessive growth of algae and water plants.
What are the downsides to eutrophication?
Overgrowth of plants on water surface prevent sunlight from reaching submerged plants. They die and are decomposed by decomposers. The decomposers use up all the oxygen in the water. Other organisms like fish die due to lack of oxygen.
How are bacteria used to treat sewage?
In an aeration tank liquid is mixed with aerobic microorganisms (bacteria). Bubbles of air are pumped into the liquid through pipes in the floor of the tank. These microorganisms absorb the organic pollutants in the water.
Anaerobic bacteria decompose the sludge. They break down the organic matter producing biogas.
Explain the increasing levels of toxic substances along the food chain. (BIOACCUMULAION/AMPLIFICATION)
E.G
Mercury is non-biodegradable and insoluble in water. It is also not excreted and thus is stored in organisms that consume it.
When consumers keep consuming organisms containing mercury, the concentration further increases in the bodies. (BIOACCUMULATION)
As organisms are eaten along the food chain, mercury is passed along the food chain, increasing the mercury concentration in the bodies of organisms along the trophic levels (BIOAMPLIFICATION)
What are reasons for conservation of species?
- Maintain biodiversity by preventing species extinction
- For scientific research
- Economic Purposes
- Maintain stable and balanced ecosystem
- Preserve wildlife and scenery for people to appreciate.
