1.3 - Energy And Equilibrium Flashcards
State the first law of thermodynamics
Energy can neither be created nor destroyed; it can only change form.
Also know as the law of conservation of energy
What happens to energy within the first law of thermodynamics
In ecosystems energy enters the system in the form of sunlight, its converted into biomass via photosynthesis, passes along the food chain as biomass, is consumed and ultimately leave as heat. Heat is released because of the inefficient transfer of energy. The total amount of energy has not changed but the amount of available energy has reduced
What is the second law of thermodynamics
In any energy conversion there is less usable energy at the end of the process than at the beginning. Energy goes from a concentrated form into a more dispensed form. Entropy increases
How does the energy change in the second law of thermodynamics referring to a food chain
At each tropic level the energy that is passed along is dispensed to different forms such as growth, movement and heat (this reduces the amount of energy available for the next level)
Define entropy
A measure of the disorder in a system
Define equilibrium
The tendency of a system to return to its original state following a disturbance
Compare “static equilibrium” and “steady state equilibrium”
In static equilibrium there is no change over time. Most non living systems are in a state of static equilibrium. A steady state equilibrium is a characteristic of an open system where there are continuos inputs and outputs of energy and matter. The system as a whole stays the same.
Give an 3 examples of steady state equilibrium
- a country population: a place will have births and deaths, but will ultimately remain unchanged
- climax ecosystem: there are no long term changes. Inputs and outputs are balanced
- human body temperature?: when it rises we sweat too coll down, stays at 37 degrees
State 3 examples of static equilibrium
- a hat on a hook: the hat is not in motion, remaining in equilibrium. There are no inputs or outputs creating change
- pile of rocks: forces within the system are balanced - no output or input
- building: no change in the system
Compare stable equilibrium and unstable equilibrium
In stable equilibrium the system tends to return to the same equilibrium after the disturbance whereas in an unstable equilibrium it returns or moves to a new equilibrium
Is a simple ecosystem or a more complex ecosystem more likely to maintain a stable equilibrium when faced with disturbance? Exaplain your answer, using examples
The more diverse and complex an ecosystem, the more resilient it tends to be as there are many interactions between different species and so equilibrium can be maintained. For example the Daintree rainforest in Queensland is a mature forest so it’s highly diverse. If a disease were to wipe out one species of trees the forest would be able to return to the original equilibrium by making new interactions. A simple ecosystem would not.
Define negative feedback
Feedback that counteracts any change away from equilibrium, contributing to stability
Outline an example of negative feedback
Global temperatures rise causing more ice caps to melt. This increases the water vapour in the air + more clouds. More solar radiation is reflected by the clouds decreasing global temperatures
Define positive feedback
Results in a further increase or decrease change in response to change in the system. Moves the system away from its original equilibrium towards instability
Outline “the vicious cycle of poverty” as an example of positive feedback
Low income -> decreased access to to education -> lower job prospects -> less income
An IB student has a lot of work to do and gets stressed. As a result, they might struggle to focus on their work, and delay in completing it. The workload piles up more and more because they aren’t getting through it, making them more stressed.
What type of feedback mechanism is being described here? Explain your answer.
Positive feedback - end result is a new equilibrium with the student less able to do work
Describe the term resilience
Refers to the tendency of a system to avoid tipping points and maintain stability through steady state equilibrium. Returns to initial state following a disturbance
Describe the term tipping point
When small changes in a system add up together and tip the equilibrium over a threshold to a new unstable equilibrium
Explain how the size of storges and the diversión y of a system can affect its resilience
The more diverse and complex an ecosystem the more resilient it tends to be as there are more interactions between species. The bigger the storage the less significant a small change would be
State and explain the resilience of the stated system:
A large forest ecosystem with high biodiversity
High
There are more interactions between organisms if the biodiversity is high. If there is a change eg. A decrease in population of a particular species through disease, those organisms that feed on it will have alternative food sources to turn to. The system will remain mostly unchanged
State and explain the resilience of the stated system:
A large field with only corn growing with small numbers of insects feeding on the corn
Low
A monoculture of corn can be wiped out by a disease - small gene pill reduced resistance to disease. Also vulnerable to pests
State and explain the resilience of the stated system:
An isolated village community in the gobi desert with a population of around 1000 people
Low/moderate
Small, isolated population has low genetic diversity. This makes population vulnerable to disease. Food quality is poor with migration the reliance is increased to moderate
State and explain the resilliance of the stated system:
The community of shanghai, china. Population roughly 24,000,000
High
Large population implies large genetic diversity. Access to varied resources. Disease does spread quickly due to high population density
Explain how the extensive use of fossil fuels, resulting in increased atmospheric levels of greenhouse gases hours gases might affect the resilience of a ocean food web
Low resilliance. More co2 and so2 due to fossil duel combustions leads to acid rain and ocean acidification. Reduces the ability of circumstances to form shells and leads to coral bleaching. Both result in the deceased of species diversity.
