Lecture 11 Flashcards
(24 cards)
What is the difference between a food chain and a food web?
A food chain represents how matter and energy are transferred from one organism to another. A food web is a complex network of food chains including all consumer-resource relationships within a community.
What is included in a single trophic level?
One trophic level includes functionally similar organisms (usually defined by how they get food)
What are heterotrophs
Heterotrophs are organisms that cannot produce its own food. Consumers are heterotrophs.
Who do primary consumers eat?
Primary producers.
What are autotrophs?
Organisms that can make their own food. Primary producers are autotrophs.
In a food pyramid, as carbon and energy are consumed, they are also ________, leaving the system.
Respired
What is gross primary productivity?
Total rate of energy (biomass, carbon) fixation by autotrophs = photosynthesis
What is net primary productivity?
Total rate of energy accumulation by autotrophs after they have they met their own energetics needs = photosynthesis - plant respiration
What is net ecosystem productivity?
Total rate of energy accumulations of the ecosystem after everyone has met their energetic needs = photosynthesis - plant respiration - other respiration
When you consider _________, ecosystems always show a pyramid trophic structure
Productivity (i.e., rates)
How does considering productivity vs biomass change the trophic structure of ecosystems?
While ecosystems will always show a pyramid trophic structure when productivity considered, structure of biomass (pools or stocks) is not constrained in this way
What is a trophic cascade?
Consumer resource interactions that alter species abundances across multiple trophic levels in a food web.
What are boxes vs what are fluxes?
Boxes (or pools or stocks) measure the quantity of something, while fluxes (or flows) measure the rate of transfer among boxes
What is a carbon source?
A carbon pool that emits more carbon that it absorbs
What is a carbon sink?
A pool that absorbs more carbon than it emits
Of the terrestrial biosphere, ocean, and atmosphere are all carbon _______. Why?
Sinks. They are growing as they take up anthropogenic carbon emissions.
What is happening to the ocean as a result of carbon absorption?
Carbon + water results in carbonic acid, causing ocean acidification
Where is the carbon in the terrestrial biosphere?
Biomass (mostly plants) and soil
Of aboveground biomass, soil organic carbon, and belowground biomass, which is the most challenging to quantify (in terms of carbon content)
Belowground biomass
What is carbon turnover time?
The average time that carbon atoms spend in a pool. This depends on how quickly it re emitted
What are some factors in carbon turmover
Decomposition (heterotrophic respiration), herbivory (heterotrophic respiration), and fire
What is example of slow carbon turnover pools.
Trees grow slows (and resist fires) and stick around for a while. Also soil carbon accumulates slowly but stick around for a long time.
