1.3 Energy and Equilibrium Flashcards
1st Law of Thermodynamics
Energy in an isolated system and is neither created nor destroyed, only changes forms.
2nd Law of Thermodynamics
the entropy of an isolated system, not in equilibrium, will tend to increase over time. this reduces amount available to do work.
Entropy Definition
The measure of disorder in a system.
Entropy is simply a quantitive measure of what the 2nd law describes: dispersal of energy in a process of our material world.
Entropy explanation
Increase of entropy from energy transformations = Reduces energy available to do work
1st Law of Thermodynamics represented in a Food Chain + Energy Production System
Solar energy → absorbed by plants → made into chemical energy → plants eaten by animals & used for energy
2nd Law of Thermodynamics represented in a Food Chain + Energy Production System
When one animal feeds off another → loss of heat (energy) in respiration and movement
More and more energy is lost as one moves up trophic levels
Inefficiency/decrease in available energy along the food chain
Steady-State equilibrium definition
occurs in open systems where there are countinous inputs and outputs of energy and matter, but the system as a whole remains in a more or less constant state. there are no long term changes but there may be small fluctuations in the short term.
Stable equilibrium definition
The tendency in a system for it to return to a previous equilibrium condition following disturbance.
Static equilibrium definition
Occurs when there is no change over time.
When it is disturbed, it either returns to equilibrium (stable) or adopts a new equilibrium (unstable)
Resilience definition + explanation
The ability of a system to return to its initial state after how a system responds to a disturbance.
The MORE resilient a system → the MORE disturbance it can deal with
e.g. in agriculture, we want stability so we can predict that the amount of food we grow is about the same each year. If this does not happen, it can lead to famine.
Factors that can increase resilience (8)
- higher temps, light+water availability, resulting in faster growth rates: tropical rain forest
- greater genetic diversity
- greater species diversity
- reduce an invasive species
- less pollution
- faster rate of reproduction (r-strategist)
- large ecosystem
- spread over a large geographical energy
Tipping points definition
Small changes in systems that tip the equilibrium over a threshold, potentially transforming into a very different system.
- changes that are hard to reverse
- long-lasting changes
- involve positive feedback
Tipping points real life example
River Eutrophication
- rain washes fertilisers from farmers fields into rivers
- extra nutrients result in excessive plants growth
- light is blocked by decomposing plant material
- oxygen levels fall + animals die
- river becomes eutrophic + takes great effort to restore
Negative feedback loop definition
Stabilises steady-state equilibrium by neutralising any deviation from an equilibrium. It results in self-regulation of a system.
Negative feedback loop example
Predator-Prey model
- When prey populations (hare) increases, there is more food for predators (lynx) so they eat+breed more predators which eat more prey so that prey numbers decrease