Lecture 23 Flashcards
Ecosystem ecology ?
emphasizes energy flow & chemical cycling between organisms & the environment (biotic + abiotic)
Energy flow?
Energy flows through the biotic component (Producer, Consumer, Decomposer) of the ecosystem
Nutrient Cycling ?
Nutrients cycle from the abiotic to the biotic & back again
nutrition of decomposers?
Heterotrophs
Digest then ingest
Most fungi, most bacteria, some protists
To recycle nutrients, an ecosystem must have, at a minimum:
producers and decomposers.
what would happen if eliminate consumers?
No one would eat the producers, all the food would be for decomposers. If we take out consumers, no pollinator, then types of plant selected for –> no pollinators.
Trophic levels
is the position it occupies in a food chain.
Primary producers: trophic level 1. They are at the bottom of all food chains
Consumers:
Primary consumers: trophic level 2
Secondary consumers: trophic level 3
Tertiary consumers: trophic level 4
Decomposers:
If they decompose a plant, they are at trophic level 2
If they decompose a tertiary consumer, they are at trophic level 5
Food webs:
Complex of interconnected food chains in an ecosystem
Each chain can have an impact on others
Trophic efficiency
It is usually about 10% , with a range of 5% to 20%
where is the energy “lost” in trophic efficiency
In the bonds: within molecules (ex amino acids) and between molecules (ex peptide bonds)
not digested, feces
cell. respiration
Why energy transfer b/w trophic levels is so low
Not all the energy in one organism enters the next.
Didn’t/couldn’t consume the entire organism
- Most of the energy that does enter the next organism is lost to feces (couldn’t digest) or to the heat of cellular respiration (recall: glucose → ATP + heat)
Why are birds & mammals < efficient than fish
BECAUSE MOST OF THE ENERGY IS LOST AS HEAT AND FISH ARE COLD BLOODED BUT THEIR METABOLIC RATE IS LOW, LESS CELLULAR RESPIRATION.
