lecture 4 ecology Flashcards
how have we defined ecosystem function so far
- species interactions
- energy and nutrient flow (how nutrients are cycled within ecosystems)
how ecosystems “work” – what is being altered
humans are altering ecosystem function
important questions we ask ourselves:
- what is a healthy ecosystem,
- does health = good function
- how does an ecosystem ‘function’
components of an ecosystem ( draw mapping)
living and non living componenets (living organisms, dead organisms) — biotic factors
(physical environment) – abiotic factors
in a sqaure (physical environment) top will be primary producers which are autotrophs, then we will have primary consumers (which consume the primary producers) then we will have secondary consumers (consume organisms further down into food web)
we will then have decomposers (feed on dead organic matter) and then we will have detritus (which is the dead organisms)
what are primary consumers examples of
herbivores
what are primary consumers, secondary consumers, and decomposers and example of
heterotrophs
what are the primary producers examples of
autrophs
what are autotrophs
organisms that make their own food/chemical energy
what re heterotrophs
organisms that get energy from consumer other organisms (living or non living)
living component – more detail definition
group of organisms that process energy and nutrients in SIMILAR ways
the compoenents are connectewd, what two ways does energy and nutrients flow – draw mapping of arrows.
between organisms and between evironment
red arrow = bw organisms
blue arrow = bw environment
– red arrow bw primary producer and primary consumer because primary consumer eats PP obtaining energy and nutrients from it.
– red arrow bw primary consumer and second consumer because second consumer eats and obtains energy from promary consumer
– red arrow between detritus and secondary because secondary die and vbecome dead organisms.
– red arrow between primary and detritus because they die and become dead organisms between decomposers and secondary because secondary also eat decomposers (some of them)
– two arrows between decomposers and detritus because decomposers can die and they also break down dead organsisms to obtain energy.
black arrows coming out of each thing and a black arrow from environmewnt to PP
how is the ecoysystem function characterized
by connenctions between components and flow of energy and nutrients
what are ecosystems powered by
majority powered by the sun
energy flow firsat step (sun, PP)
Primary producers capture radiants energy )photosynthesis) and store it as chemical energy (molecular bonds in orangic compounds (carbohydrate, sugars, ATP))
Energy flow second step (PP, PC)
Ecosystems transfer chemical energy through consumption (transfer to consumers) and Death (transfer to detritus)
detritus and consumptions –
not sonsumed directly, usually floats in ewaters, or falls to the ground, energy is locked up and decomposers will feed on the nutrients.
what is also happening as energy is entering the ecosysatem –
energy is also lost (heat Loss) through respiration – therefore the energy flow is not a perfect loop.
what direction is energy flow
irt is a one-way flow – enters as radiant energy, stored and transferred as chemical energy, and leaves as heat energy. – has to be a continued input of sunlight to maintain one-way energy flow
how can we compare ecosystem energy flow
- amount of energy reaching ecosystem
- efficiency of energy capture
- transfer rates
- rates of energy loss
ecosystem nutrient cycling
more of a closed loop
- we need nutrients in addition to sunlight to build new biomass.
- nitrogen compoinds
- flows from organisms to physical enviironment and back to ecosystem via the primary producers.
– circular flow of nutrients – nutrients mostly retained – cycle bw organisms and physical enviornment
CO2 in the cycle
plants get CO2 (gas) from atmosphere and convert it to organic carbon. Org. C is transfewrreed among components. CO2 is returned into atmosphere through respiration.
what component plays an important role in nutrient cycling
decomposers
– invertebrates, fungi, bacteria
– they obtain chemical energy and nutrients that qwere locked up in detritus and return some nutrients back to physical environmeny to keep flow of nutrients going
how can we compare ecosystem nutrient cycles - give examples for some
-nutrient stores in physicasl environment (soil [diff levels of nutrients])
- efficiency of nutrient uptake (macroalgae (high nutrient) vs corals (low nutrient)
- transfer rates
- retention of nutrients (retained within ecosystem)
little recap of nutrient and energy flow
– an ecosystem processes and transfers energy and nutrients
– fueled by energy from outside the ecosystem
– cycle and recylce nutrients from and to the physical enviornment
