Lecture 2: Ecosystem Processes Flashcards
Regardless of level of organization…
organisms and ecosystems generally made of same stuff
Hierarchies in nature are:
- nested
- interdependent / integrated system
- non-reducible
Hierarchical thinking
approach to studying complex systems w/o using full reductionism
ecosystem
biotic community and the abiotic environment with which it interactd
community
all populations inhabiting a given area and interacting directly/indirectly
population
all individuals of the same species living in a given area at a given time
organization of hierarchy sample order
landscape
ecosystem
community
population
organism
system
“regularly interacting & interdependent components forming a unified whole”
Which levels display homeostasis (equilibrium)?
organism and below
Which levels show homeorrhesis (pulsing states)?
above organism
Ecosystem ecology
- focus specifically on feedbacks between abiotic and biotic components of ecosystem
- links other disciplines @ broader/higher & lower/mechanistic scales
- ecosystems = complex adaptive systems
Complex adaptive systems
system in which perfect understanding of components =/= perfect understanding of whole system behavior
Characteristics of Complex Adaptive Systems
- Components
- Interactions
- Feedbacks
- Self-organization
- Adaptation
Components
- many
- open system
- no central command, control, plan
Interactions
- structure & behavior self-organize through these
Feedbacks
- something about that interaction feeds back to change X
a) predator-prey networks
b) complex networks
Self-organization
- ecosystems tend to follow simple rules & resource availability (self-organization default behavior)
- ult. resource: SUN
- organisms’ growth limited by resources & metabolism
- interactions affect resource acquisition & metabolism
1) components interact
2) local feedbacks form
3) feedbacks that allow organisms to persist are self-reinforcing
4) local systems emerge
5) networks of local structures
6) basic biological & ecological rules mean that similar patterns emerge
Adaptation
- each component slightly different
- variation affect interaction outcomes
- each local interaction has consequence & judge
- consequence: effect on fitness
- judge is natural selection
- populations adapt to one another through feedbacks
Environmental change
affects general conditions & interactions
Emergent properties
property of unit that cannot be predicted from studying its individual components
examples:
* trophic structures
* collective behaviors
* atmosphere regulation
* nutrient cycling
* diversity productivity relationships
Most (but not all) ecosystems:
- gain energy from Sun
- gain materials from air & rocks
- transfer materials & energy among different components of system
- release energy & materials back –> environment
