Topic 1 - SystemsIB Topics 1.1.1, 1.1.2, 1.1.3

Systems A system is an

assemblage of parts and the relationships between them that constitute a whole

Examples:

System Types Open

Both matter and energy are exchanged across the boundaries of the system

System Types Closed

Energy is exchanged, but no matter is exchanged

System Types Isolated

No matter or energy is exchanged

System Components Systems consist of:

Storages Of matter and

energy Flows

Inputs into, outputs out of the system

Processes Transfer or

transform energy or matter

Gaia Proposed by James

Lovelock in the 1970s

Suggests that life on Earth helps to regulate Earth’s conditions Ocean salinity Global temp Oxygen content

Gaia Main Ideas “Earth is a self-

regulating superorganism”

“Living and non-living components work together”

“Everything on Earth is connected”

“Earth will continue after humans”

Topic 1 - EnergyIB Topic 1.1.4

Energy Energy exists in

multiple forms: Light Chemical Electrical Heat

1st Law of Thermodynamics Energy cannot be

created or destroyed, it can only change forms

1st Law of Thermodynamics (related to ecosystems) All the energy into a system must equal

the energy stored plus energy lost

2nd Law of Thermodynamics Energy goes from

a concentrated form to a dispersed form

(Useable energy to non-useable energy)

2nd Law of Thermodynamics (related to ecosystems) New energy needs

to be added to the system

Topic 1 - EquilibriaIB Topic 1.1.5

Equilibrium Static Equilibrium

No input or outputs of matter or energy

No change in the system over time

Equilibrium Steady-State

Equilibrium Inputs and

outputs of matter and energy

System remains stable over time

Stable vs Unstable Equilibrium Stable Unstable

Topic 1 - FeedbackIB Topic 1.1.6

Feedback Positive Feedback

A change in the system leads to increased change

The system goes away from equilibrium

Negative Feedback Changes in the

system lead to stability

The system maintains equilibrium

Examples: Global warming causes methane release

from permafrost

Examples: Global warming causes ice to melt and

water absorbs sunlight

Examples: Lynx – Hare population

Examples: Increased CO2 increases photosynthesis

Topic 1 – Transfers and TransformationsIB Topic 1.1.7

Transformations The change of

energy or matter to a new product

Involve a change of state

Transfers Energy and matter

move through a system without changing state

Usually involve a change in location

Topic 1 – Flows & StoragesIB Topic 1.1.8

Flows Inputs and

Outputs Energy and matter

moving from one place to another

Storages (stocks) Matter and energy

is stored in stocks or reservoirs

Topic 1 - ModelsIB Topic 1.1.10

Models A model can be

any representation of a real system.

Ex: Aquarium Diagram Computer Model

Example: Make a model

with the following terms: Forest floor People Trees Animals Forest Plants Soil

Models Advantages Disadvantages