LEC 20 Flashcards
Trophic interactions are feeding relationships that link organisms in an ecosystem based on _________________________
What they eat and what eats them
Each trophic level, or feeding category, is based on the number of steps by which it is separated from the _________ in the ecosystem
Autotrophs
The first (basal) trophic level consists of _____________
Autotrophs (primary producers)
The first trophic level generates __________ using sunlight (photosynthesis) or inorganic molecules (chemosynthesis)
Chemical energy (NPP)
All other trophic levels consists of
Heterotrophs (consumers)
The second trophic level includes _______ that feed on _______-
Herbivores, autotrophs
The third trophic level includes __________ that feed on ___________-
Carnivores, herbivores
The fourth (and higher) trophic levels include _________ that feed on _______________
Carnivores, other carnivores
There are ______________
Levels within levels
Some organisms do not fit conveniently into trophic levels
Omnivores feed at multiple levels:
Coyotes are examples of omnivores, consuming:
- Autotrophs (fruits, berries)
- Herbivores (Grasshoppers)
- Carnivores
- Old leather boots
All organisms in an ecosystem are either __________________ or ________________________
Consumed by other organisms, enter the pool of dead organic matter (detritus)
In any ecosystem, only a small portion of NPP is _________, while most ends up as ________-
Consumed, detritus
Dead plant, animal, and microbial matter (detritus), as well as wastes (feces), are consumed by ___________________ during the process of ____________
Decomposers (detritivores), decomposition
Detritus is considered part of the _______ trophic level, so ___________ are included with the ______ level
First, detritivores, second
Understand that detritus does NOT have any NPP, but still can be considered on the first trophic level
A ___________ is a graphical representation of __________________ with respect to trophic relationships
Trophic pyramids, energy or biomass
Because a proportion of the energy at each trophic level is _____ during transfer to the next trophic level, _____________ may never be ________-
Lost, energy pyramids, inverted
It is possible for ___________ to be _________ (more biomass at higher trophic levels)
Biomass pyramids, inverted
Examples are usually ______________
Aquatic (marine, specifically)
-Large baleen whales feeding on tiny phyto- or zooplankton with short lifespans and high turnover
Only ________ of energy from the first trophic level makes it to the next trophic level
~10%
Trophic efficiency is a measure of how much energy from one trophic level makes it to the next trophic level. Trophic efficiency consists of three components:
1) Consumption efficiency
2) Assimilation efficiency
3) Production efficiency
Consumption efficiency
Measures how much energy at one trophic level is consumed by the next trophic level
Ranges from ~5% to ~50% in different ecosystems
The rest of the energy is simply not eaten
All autotrophic energy may not be consumed by herbivores due to:
- The autotrohp’s chemical (screenplay compounds) and physical (spines and thorns) defenses
- Nutrient-poor components (wood) compared to nutrient-rich components (leaves)
Assimilation efficiency
Measures how much energy from one trophic level is incorporated into the next trophic level by digestion and used for maintenance and defense
Ranges from ~20% to ~80%
The energy that is not assimilated is lost as wastes (feces)
Assimilation efficiency is __________ in carnivores than herbivores because:
GREATER;
Plant matter contains much indigestible material, such as cellulose and lignin
Animals have similar carbon to nitrogen ratios as the carnivores consuming them, so they can more easily be assimilated
Production efficiency
Measures how much energy from one trophic level goes into the production of new biomass for the next trophic level (in the form of growth and reproduction)
Ranges from ~1% to ~50%
The rest of the energy is lost as heat during cellular respiration
