Lecture 4 + 5 Flashcards
______ determines the route that energy flows through the ecosystem
Trophic structure determines the route that energy flows through the ecosystem
Trophic level
a link in the food chain
Detritivore/decomposer: examples
organisms include earthworms, and vultures, but the most important decomposers are bacteria and fungi
Decomposition releases ________ compounds (e.g., CO2, NH4, PO4, etc) that can be reused by producers (this maintains ecosystem productivity)
Decomposition releases inorganic compounds (e.g., CO2, NH4, PO4, etc) that can be reused by producers (this maintains ecosystem productivity)
Food chains vary in length, not all have ___ levels
Food chains vary in length, not all have five levels
Omnivory - example
bears
secondary consumers
carnivores
mixotrophic
when matter passes through animal’s multiple times, and microorganisms can be mixotrophic (auto and hetero)
Many microorganisms make a living autotrophically and heterotrophically
e.g., Euglena are capable of engulfing prey and photosynthesizing simultaneously
Net primary production (NPP)
is the remaining energy that heterotrophic organisms (consumers) may use
Secondary production
the rate of accumulation of biomass by heterotrophic or consumer organisms
Terresterial habitats units
g C m-2 day-1
Aquatic habitats units
g C m-3 day-1
Three fundamental processes detail energy transfer efficiencies:
- Ingestion or consumption efficiency
- Assimilation efficiency
- Production efficiency
Ingestion efficiency (IE)
- % of total productivity available at one trophic level that is consumed (ingested) by the trophic level above
- For primary consumers, IE is the % of NPP that finds its way into the guts of herbivores
- Generally more plant biomass is available than can be eaten
IE for herbivores are approximately 5% in forests, 25% in grasslands and 50% in phytoplankton dominated communities.
IE for secondary consumers ranges from______.
IE for secondary consumers ranges from 5% to 100%.
Consumption of plant tissues has an AE of ~ ____
Consumption of plant tissues has an AE of ~30%
Production efficiency (PE)
PE is the proportion of the assimilated energy that is converted into new biomass (tissue)– the remainder is largely lost to respiration
The resulting increase in biomass is secondary production
Amount of energy available to an upper trophic level is calculated as:
IE x AE x PE = trophic transfer efficiency
The number of trophic levels in a food chain is ____
The number of trophic levels in a food chain is finite
Detritus: (plant-animal centric definition of your text)
fresh to partly decomposed plant and animal
matter
Detrital systems are responsible for the majority of
________ production, and consequently heat loss, in
most ecosystems of the world
Detrital systems are responsible for the majority of
secondary production, and consequently heat loss, in
most ecosystems of the world,
For example, in the yellow-popular forest mentioned
earlier, 35% of GPP goes to the detrital food chain
GFC (Grazing Food Chain)—->
NPP, Herbivores, Carnivores
DFC (Detritus Food Chain) —->
Detritus, Decomposer Herbivore, Carnivores
In detrital food chains the flow of energy is not unidirectional.
Detritus food chains dominate in most ecosystems.
