1.3 energy and equilibria

Question 1

first law of thermodynamics

Answer 1

energy can neither be created nor destroyed, but only transformed

Question 2

entropy

Answer 2

increase in disorder and randomness in a system

Question 3

second law of thermodynamics

Answer 3

entropy of a system increases over time; the only way to avoid entropy is a continuous input of additional energy

Question 4

what does an increase in entropy mean?

Answer 4

a decline in the amount of energy available to do work

Question 5

complex systems

Answer 5

• often exist within a steady state equilibrium
• controlled by a series of positive and negative feedback loops

Question 6

negative feedback

Answer 6

• counteracts change and works to return a system to a state of equilibrium

Question 7

positive feedback

Answer 7

• amplifies change and moves a system away from a state of equilibrium
• temp increases –> ice melts –> lower ocean albedo –> more solar energy –> temp increases

Question 8

daisy world model

Answer 8

• negative feedback loop
• white daisies reflect heat, atmosphere colder, die because it’s too cold –> black daisies absorb heat, atmosphere warmer, die because it’s too warm
• more white daisies –> high albedo –> lower temp –> more black daisies –> lower albedo –> higher temp

Question 9

albedo

Answer 9

measure of % of light reflected - reflectivity of the surface

Question 10

steady-state system

Answer 10

• inputs/outputs remain roughly balanced
• system exists within set parameters
• if inputs or outputs vary too much, system is overwhelmed and positive feedback pushes it over a tipping point and into a new steady state

Question 11

daisyworld inputs, outputs, and store

Answer 11

input: light energy
output: temp
store: daisies (mass)

Question 12

succession

Answer 12

how the structure of a biological community changes over time
- vegetation and species

Question 13

snowball earth

Answer 13

• runaway ice house effect
• more glaciers –> more albedo –> more sun energy reflected –> lower temp

Question 14

tipping point

Answer 14

a part of the human-environment system that can lever far-reaching change in the system
- the point at which a series of small changes or incidents becomes significant enough to cause a larger, more important change.
- the critical point in a system beyond which a significant and often unstoppable effect or change takes place

Question 15

case study - coral bleaching

Answer 15

• great barrier reef, australia
• bleaching is a stress response due to harmful chemicals
• reefs can recover but because of the frequency it prevents the recovery process –> tipping point, unable to recover, coral death
• corals die –> more algae –> less O2 levels

Question 16

ecosystem stability + factors affecting it

Answer 16

• different ecosystems have different abilities to resist push factors and maintain their equilibrium
• climate, biodiversity, and frequency of disturbance

Question 17

resistant ecosystems

Answer 17

maintain ‘business as usual’ in response to a disturbance: negative feedback maintains conditions within a dynamic equilibria

Question 18

resiliant ecosystems

Answer 18

initially impacted by a disturbance, but are able to return to a steady state afterwards

Question 19

consequences of tipping points

Answer 19

• loss of biodiversity –> habitat destruction, species extinctions, or shifts in species composition due to changes in environmental conditions
• collapse of ecosystem services –> tipping points can disrupt ecosystem services, leading to decrease in agricultural productivity, water quality, and resilience to natural disasters