ESS Topic 1 exam - Foundations of ESS

Subtopics: 1.1 (Environmental Value Systems), 1.2 (Systems & Models), 1.3 (Energy & Equilibrium)

big ideas for 1.1

1) there is a spectrum of EVSs, each with its own premises and implications

2) historical events, among other influences, affect the development of EVSs and environmental history movements

Environmental Value System

a worldview that shapes the way people perceive and evaluate environmental issues (cultural, economic, & socio-political influences)

ecocentric

nature centered, holistic + sustainable worldview, minimum disturbance of nature - deep and soft ecologists

anthropocentric

people/human-centered, humans are responsible for sustainable global systems through control of population + resource use - environmental managers

technocentric

technology centered, tech provides solutions for any environmental issues - cornucopia (mankind can find themselves out of any issue)

environmental value system + spectrum of EVS

intrinsic value

inward value of nature regardless of its practical (economic) use to humans (ethical, spiritual, philosophical)

environmental history movement

big ideas for 1.2

1) A systems approach can help in the study of complex environmental issues

2) The use of systems and models simplifies interactions but may provide a more holistic view without reducing issues to single processes

reductionist

look @ indiv. parts

hollistic

look @ whole

system

assemblage of parts and their relationship forms a function entirety w/inputs and outputs (ex. computers)

emergent properties

the whole can do things that the indiv. parts cannot

societal systems

• value systems

• economic systems

• social systems

influenced by geographic location, religion, culture, etc

earth as a system

includes abiotic (non-living) & biotic (living) components

• biosphere

• atmosphere

• hydrosphere

• lithosphere

gaia hypothesis

earth functions as a single living global system w/homeostatic mechanisms (ex. temp, climate, ocean salinity, etc)

systems elements

• inputs, symbol: arrows in →, described as: energy or matter that enters a system

• outputs, symbol: arrows out ←, described as: something produced @ the end of a system

• storages, symbol: box, described as: where energy/matter is accumulated

• flows, symbol: arrows, described as: movement of energy/matter

• boundaries, symbol: lines —, described as: outer limit of a system

* know how to draw these systems

* energy enters system as sunlight, matter cycles through

transformation

moves energy & matter, but in the process of doing so there is a change in state or form (ex. water → liquid → gas)

transfer

moves energy/matter from one place to another w/out changing it (ex. water flowing across land)

open system

system in which both materials + energy are exchanged across boundaries (mass in, mass out, energy in, energy out)

closed system

system where energy is exchanged across boundaries, but matter is not : RARE (approximation: global geochemical cycles like water cycle)

isolated system

no exchange of energy or material across system boundaries (only hypothetical)

models

simplified version of reality → used to understand how system works + predict

advantages:

• predict & simplify complex systems

• brings out patterns

• inputs & outputs exchanged + examined w/out waiting for real events

disadvantages:

• lack of detail/accuracy

• rely on expertise of those making them

• different interpretations possible

• vested interests → political hijack

big ideas for 1.3

1)The laws of thermodynamics govern the flow of energy in a system and the ability to do work

2) Systems can exist in alternative stable states or as equilibria between which there are tipping points, 

3) Destabilizing position feedback mechanisms will drive systems toward these tipping points, whereas stabilizing negative feedback mechanisms will resist such changes

first law of thermodynamics

energy cannot be created or destroyed; it can change from one form to another

• all energy comes from sunlight

• less energy at higher trophic levels

• in open systems energy is constantly entering, but never increasing

second law of thermodynamics

when energy is being converted to one form from another, some of it is lost as heat: entropy (measure of how much is lost)

• energy lost at each trophic level in a food chain is about 90%

• higher trophic levels must consume more

steady-state equilibrium

• maintains a steady state due to constant flow of inputs and outputs

  • ecological systems require inputs/outputs

static equilibrium

always in balance, no inputs/outputs, inanimate objects

• doesn’t apply to natural systems

positive feedback loop

amplifies change → deviation from stability, diverges from equilibrium

• removing forest amplifies erosion

negative feedback loop

dampens effects and promotes return to stability

• predator/prey relationships

resilience

capacity of an ecosystem to respond to a disturbance (better w/more biodiversity, + alternate energy/matter pathways)

threshold

critical points at which the systems response and behavior changes abruptly (really hard to predict, changes hard to reverse)

push factor

what is moving it away from equilibrium

some important events during the environmental movement (make sure to know details about a couple)

• Founding of IUCN (Oct. 5, 1948)

• Minamata (1950s)

• Rachel Carson’s Silent Spring Published (1962)

• Bhopal (Dec. 3, 1984)

• Chernobyl (April 26, 1986)