1.3: Energy and Equilibrium Flashcards
First law of thermodynamics
The law of conservation:
Energy can neither be created nor destroyed, but only transformed
(total amount energy in an isolated system doesn’t change but the energy can transform)
Second law of thermodynamics
The entropy of a system increases over time; the only way to avoid entropy is a continuous input of additional energy
What is entropy? How can it be avoided?
Entropy is the increase in disorder and randomness in a system
A continuous input of energy into the system
What state do complex systems often exist in? What does this mean? How is this state controlled?
A steady state equillibrium:
- inputs and outputs are balanced within a consistent range
It is controlled by a series of positive and negative feedback loops
What is negative feedback?
Negative feedback counteracts change
What is positive feedback?
Positive feedback amplifies change and moves away from a state of equilibrium - to a possible tipping point.
What is daisy world? What were the components?
Daisy world is a computer simulation created by James Lovelock that simplifies how states and equilibrium work.
The white daisies have high albedo (reflect light) and prefer high temperatures.
The black daisies have low albedo (absorbs light) and prefers low temperatures.
How does daisy world demonstrate states and what type of state is it? What would it take to change this type of state?
Daisy world demonstrates how negative feedback counteracts change and keeps it in a steady-state equilibrium.
More black = higher temp = more white = lower temp = more black…
To change the state of equilibrium and enter.a new state, the abiotic factors would have to be changed, influencing a positive feedback cycle that would lead to a tipping point.
Steady state systems:
- input and outputs oscillate between set parameters to stay balanced
- storage remains roughly constant
- maintained by negative feedback
Two examples of positive feedback in the global climate system:
increase temp = more ice melting = decrease surface albedo = more light absorbed = increases temp
increase temp = increase rate of organic matter decay = more release of co2 = increase temp
Two examples of negative feedback in the global climate system:
increase temp = increase precipitation = increase in clouds = increases albedo = less light absorbed = lower temp = less precipitation …
increase co2 = more plant growth = more co2 absorbed
What happens when there is more positive than negative feedback? What is an example of this?
A tipping point will be reached
The system will transition to a new alternative state in a new equilibrium
Can also be a result of random events
Succession is an example of the change to a new state with a new equilibrium in the same location
Ecosystem stability:
what are push factors? what are these push factors?
Push factors are disturbances in an ecosystem
1. Climate
2. Biodiversity and trophic complexity
3. Nutrient stores
4. Frequency of disturbance
Coral bleaching case study
2 alternative states:
1. Healthy state:
- healthy coral
- good mix algae and coral
- Coral bleaching:
- a stress response due to change in abiotic factors (temp, pH)
- in a new alternative state
Explain each push factor:
- Climate:
- tropical/temperate climates > polar/desert biomes - Biodiversity and trophic complexity:
More species + food chain links are more stable. (Removing species will destabilise these systems) - Nutrient stores:
large nutrient stores > small stores - Frequency of disturbance: easier to resist small, infrequent disturbances than large or more frequent ones
