Ecosystem Structure/Function Flashcards
exam questions
What is negative feedback?
This refers to changes within an ecosystem; components cancelling each other over the long term.
What is positive feedback?
Components within an ecosystem reinforce the same result continuously, over time.
How do positive and negative feedback function to affect and moderate the environmental process of population growth?
Population growth refers to the concept of an increasing population = an increase in reproduction. The increase of reproduction then results in a further increase of the population size. This turns into a continuous cycle or a positive feedback loop.
A negative feedback loop would be if the population stated previously, grew to be a size that surpassed the ecological capacity resulting in an imbalance. The population would require more resources than what the environment can provide but due to the resources being limited, the population begins to die and then begins reproducing at a much lower rate.
How do positive and negative feedback function to affect and moderate the environmental process of carbon dioxide concentrations in the atmosphere?
Positive feedback of CO2 happens due to the increase of carbon in the atmosphere from human activities or natural causes working to further heat the planet. By heating the planet, more carbon is then released into the atmosphere through evaporation from the ocean or melting ice. This melt works to release more carbon from the previously frozen carbon sinks or from the thawing of decomposing organisms. Resulting in a continuous cycle or positive feedback loop of carbon heating the planet, and the higher temperature releasing previously stored carbon.
Negative Feedback would be introducing a component to reduce the amount of carbon in the atmosphere such as reducing emissions or planting more trees and vegetation to absorb the carbon.
What is a food chain?
A food chain is a part of a food web, it depicts who eats whom in a linear fashion whereas a food web encompasses all organisms and their interconnectedness.
How is a food chain structured?
A food chain is structured in terms of four different trophic levels that represent the pyramid of energy.
Level One - Producers (plants)
Level Two - Primary Consumers (herbivores)
Level Three - Secondary Consumer (omnivores/carnivores)
Level Four - Tertiary Consumers (carnivores)
Decomposers
What laws govern the flow of energy in ecosystems?
The first and second law of thermodynamics are especially relevant to the flow of energy.
1st - Energy cannot be created nor destroyed but can be transformed.
2nd - Energy transformations are incredibly inefficient.
What evidence is there proving that the laws of thermodynamics exist in the ecosystem?
Evidence of the first law existing is seen through the process of photosynthesis; plants and vegetation convert solar energy into food.
Evidence of the second law is clear when considering the population sizes seen at each trophic level. A tremendous amount of energy is lost upon transformation, there are significantly more plants than there are tertiary consumers because by the time the tertiary consumer receives the energy from their prey, it has already been transformed and lost most of the energy that the plants originally held.
What is an ecosystem?
A biological community of organisms interacting with each other as well as with their abiotic environment.
How do you define an ecosystem’s boundaries
Ecosystem boundaries are defined by gradients of change in environmental conditions.
ex. a forest ecosystem with a very clear boundary of a lake ecosystem.
What is an example of a highly productive aquatic system? An aquatic ecosystem that is not very productive? Why is there such a disparity between productivity levels of these ecosystems?
Highly Productive - Coral Reef
Less Productive - Deep Ocean
Coral reefs exist in shallow waters allowing for the water to have a warmer temperature as well as the shallow depth allows for vegetation to receive sunlight. Coral within the reef also acts as a form of protection for other organisms.
Deep oceans are not as productive because sunlight can simply not penetrate through the depths of the water. No sunlight means no photosynthesis, which means only very specific organisms with special adaptations can live within the deep ocean.
What is the effect of the second law of thermodynamics on pyramids of energy and biomass?
In line with the second law, there is a tendency for numbers and quantities of biomass and energy to decrease along food chains; therefore the pyramids become narrower as one ascends (the size of each level in the pyramid is reflective of the number of organisms that belong to each level).
Through which pathway(s) have humans profoundly influenced the nitrogen cycle?
Through increasing the amount of nitrogen found in the biosphere from burning fossil fuels, there is now danger of phenomenon such as acid rain occurring from the excess nitrogen which results in harm done to infrastructure, biodiversity, and soil composition.
Pathway - Lithosphere (fossil fuels), to the Atmosphere (burning of fossil fuels), to the Biosphere (nitrogen mixing with other compounds to create acid rain which falls to earths surface)
Through which pathway(s) have humans profoundly influenced the carbon cycle?
Through the burning of fossil fuels, humans have affect the amount of carbon within the atmosphere to where the earth is now in a positive feedback loop of heating the plant, thawing carbon stores which are then released to the atmosphere and heat the plant further.
Pathway - Lithosphere (fossil fuels) to the Atmosphere (burning of fossil fuels)
Through which pathway(s) have humans profoundly influenced the phosphorus cycle?
The use of phosphorus for fertilizer is an example of people affecting the cycle of phosphorus. This excess of phosphorus can result in the over abundant growth of certain plants. Phosphorus normally has a limiting factor in growth due to limited supply but through fertilizers, issues with cyanobacteria, for example, have arisen due to an excess of nurtrients that contributes to excess growth.
Pathway - Lithosphere to Biosphere
