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