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Communities and Ecosystems - Coggle Diagram
Communities and Ecosystems
Essential idea: Changes in community structure affect and are affected by organisms.
Food Web
A food web shows all the possible food chains in a community. A food web is a diagram that shows how food chains are linked together into more complex feeding relationships within a community.
Most species occupy different trophic levels in multiple food chains. Many species cannot be classified as belonging only to one trophic level. For example, many animals feed on both producers and consumers, putting them in the level of primary and secondary consumer.
To summarize: Organisms exist within a food web, food webs consist of many interlinked food chains, organisms exist in multiple food chains often at different trophic levels, when stating an organism's trophic level it must be done so relative to a particular food chain.
Gersmehl diagrams
These diagrams demonstrate the inter-relationships between nutrient stores and flows between taiga, desert, and tropical rainforest.
Sinks for nutrient storage: Biomass (flora and fauna), litter, soil
They were first developed in 1976 to demonstrate the difference between nutrient flow and storage between ecosystems.
When used to analyze a particular ecosystem: Diameter of sinks are proportional to the mass of nutrients stored in each sink, the thickness of the arrows are proportional to the rate of nutrient flow.
Nutrient inputs into the ecosystem: Nutrients dissolved in raindrops and nutrients from weathered rocks.
Nutrient outputs from the ecosystem: Nutrients lost through surface runoff, nutrients lost through teaching
Taiga, Desert and Tropical Rainforest
Taiga (temperate forest): Litter (spine needles) is the main store, slow rate of nutrient transfer between stores because of cold temperature.
Desert: Soil is the main store, slow rate of nutrient transfer between stores (except for the transfer from biomass to litter) because of dry conditions.
Tropical rainforest: Biomass is the main store (soil is nutrient poor), fast rate of nutrient transfer between stores because of warm and wet conditions.
Gross production vs. Net production
Energy is not entirely lost; organisms do trap some of the energy in the form of biomass.
Gross production (GP) = total amount of energy trapped in organic matter produced by plants in an ecosystem.
Net production (NP) = GP - energy lost through respiration. Amount of biomass that is available to the next trophic level.
Net production (the amount of organic matter remaining after respiration) = Gross production (the total amount of organic matter produced in an ecosystem) - Respiration (Stored energy used in the cellular production of ATP)
Organic matter (starch, proteins, and structural molecules, a lot of stored energy and nutrients are used by each individual) = becomes Biomass (the total dry mass of organic matter organisms or ecosystems)
Conversion Ratios
Conversion ratio in sustainable food production practices. In commercial food production, farmers measure the food conversion ratio. It is a measure of the animal's efficiency in converting feed mass into the desired output.
FCR = mass of the food eaten (g) / (increase in) desired output (g) (per specific time period)
Low FCR: A good low FCR is obtained by minimizing the losses of energy by respiration, for example restricting animal movement, slaughtering the animal at a young age, and optimizing feed so it is efficiently digested.
Comparison of pyramids of energy: Pyramids of energy show the flow of energy between trophic levels. Measured in units of energy per unit area per unit time: kj m^-2 y^-1
Transfer of energy is never 100% efficient. Around 90% of energy is lost between trophic levels: not ingested (eaten), not digested or assimilated, excreted, lost as heat from respiration.
Reasons for high net productivity in an ecosystem
High primary productivity (by producers) means more energy available to the ecosystem.
The higher the efficiency of energy transfer between trophic levels the higher the net productivity. Energy transfer is typically 10%.
Higher the primary productivity and greater the efficiency of energy transfer mean that more energy is available at high trophic levels,
Biome is a geographic area that has a particular climate and sustains a specific community of plants and animals.
Biosphere is the total of all areas where living things are found, for example the totality of biomes.
The main factors affecting the distribution of biomes is temperature and rainfall.
A climograph is a diagram which shows the relative combination of temperature and precipitation in an area.
Ecological succession: the predictable and orderly changes in composition of an ecosystem over time.
Primary: the emergence of an entirely new ecosystem, such as volcanic island.
Secondary: the replacement of one ecosystem by another following environmental change.
During succession, living organisms change the abiotic environment.
Disturbance influences the structure and rate of change within ecosystems. Disturbance can be natural or caused by human activity.
Human practices can accelerate the flow of matter into and out of ecosystems. This by implication alters the nutrient cycling in ecosystens.