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.
