IB ESS EXAM | STUDY GUIDE | 2026
System - Answers - An assemblage of parts and their relationship forming a functioning
entirely or whole
Open System - Answers - Exchanges matter AND energy
Closed System - Answers - Exchanges ONLY energy
Isolated System - Answers - DOES NOT exchange matter or energy. Theoretical.
1st Law of Thermodyamics - Answers - Energy is neither created nor destroyed. IT
ONLY CHANGES FORMS.
2nd Law of Thermodynamics - Answers - The entropy of a closed system increases.
When energy is transformed into work, some energy is always lost as waste and/or heat
Steady-State Equilibrium - Answers - In open systems.
Continuous inputs and outputs of energy and matter.
The system as a whole remains in a constant state.
There are no long term changes.
Static Equilibrium - Answers - There is no change over time.
When the state of equilibrium is distributed, the system adapts a new equilibrium.
Stable Equilibrium - Answers - The system returns to the same equilibrium after a
disturbance.
Unstable Equilibrium - Answers - The system returns to a new equilibrium after a
disturbance.
Positive Feedback - Answers - Results in a FURTHER DECREASE OF OUTPUT.
The system is destabilized and pushed into a new state of equilibrium.
Negative Feedback - Answers - Tends to stabilize systems in the event of a
disturbance.
Transfers- Literal movement. - Answers - Movement of material through living
organisms.
Movement of material in non-living processes.
The movement of energy.
Transformations- Changing from one thing to another. - Answers - Matter to matter.
Energy to energy.
, Matter to energy.
Energy to matter.
The Gaia Hypothesis - Answers - The Earth is a living organism/system.
Biotic Factors - Answers - Living components
Abiotic Factors - Answers - Non-living physical and chemical components
Species - Answers - A particular type of organism
Population - Answers - A group of individuals of the same species living in the same
area at the same time and are capable of interbreeding.
Habitat - Answers - The environment where a species normally lives.
Ecological Niche - Answers - The role of an organism.
Community - Answers - A group of populations living and interacting with each other in
a common habitat.
Ecosystem - Answers - A community of independent organism (biotic factors) and the
physical environment (abiotic factors) which they inhabit.
Biome - Answers - A collection of ecosystems sharing common climatic conditions.
Respiration - Answers - The process of breaking down food to release energy.
Respiration Formula - Answers - C6H12O6 + O2 -> CO2 + H2O + ATP
Photosynthesis - Answers - The process in which producers make their own glucose
and produce water and carbon dioxide.
Photosynthesis Formula - Answers - CO2 + H20 -> C6H12O6 + O2
Biomass - Answers - The living mass of an organism(s).
It's dry mass.
Gross Primary Productivity - Answers - The total gain in energy/biomass per unit area
per unit time BY PRODUCERS.
Gross Secondary Productivity - Answers - The total gain in energy/biomass per unit
area per time BY CONSUMERS.
Net Productivity - Answers - The same thing as Gross Productivity, but after losses from
respiration.
System - Answers - An assemblage of parts and their relationship forming a functioning
entirely or whole
Open System - Answers - Exchanges matter AND energy
Closed System - Answers - Exchanges ONLY energy
Isolated System - Answers - DOES NOT exchange matter or energy. Theoretical.
1st Law of Thermodyamics - Answers - Energy is neither created nor destroyed. IT
ONLY CHANGES FORMS.
2nd Law of Thermodynamics - Answers - The entropy of a closed system increases.
When energy is transformed into work, some energy is always lost as waste and/or heat
Steady-State Equilibrium - Answers - In open systems.
Continuous inputs and outputs of energy and matter.
The system as a whole remains in a constant state.
There are no long term changes.
Static Equilibrium - Answers - There is no change over time.
When the state of equilibrium is distributed, the system adapts a new equilibrium.
Stable Equilibrium - Answers - The system returns to the same equilibrium after a
disturbance.
Unstable Equilibrium - Answers - The system returns to a new equilibrium after a
disturbance.
Positive Feedback - Answers - Results in a FURTHER DECREASE OF OUTPUT.
The system is destabilized and pushed into a new state of equilibrium.
Negative Feedback - Answers - Tends to stabilize systems in the event of a
disturbance.
Transfers- Literal movement. - Answers - Movement of material through living
organisms.
Movement of material in non-living processes.
The movement of energy.
Transformations- Changing from one thing to another. - Answers - Matter to matter.
Energy to energy.
, Matter to energy.
Energy to matter.
The Gaia Hypothesis - Answers - The Earth is a living organism/system.
Biotic Factors - Answers - Living components
Abiotic Factors - Answers - Non-living physical and chemical components
Species - Answers - A particular type of organism
Population - Answers - A group of individuals of the same species living in the same
area at the same time and are capable of interbreeding.
Habitat - Answers - The environment where a species normally lives.
Ecological Niche - Answers - The role of an organism.
Community - Answers - A group of populations living and interacting with each other in
a common habitat.
Ecosystem - Answers - A community of independent organism (biotic factors) and the
physical environment (abiotic factors) which they inhabit.
Biome - Answers - A collection of ecosystems sharing common climatic conditions.
Respiration - Answers - The process of breaking down food to release energy.
Respiration Formula - Answers - C6H12O6 + O2 -> CO2 + H2O + ATP
Photosynthesis - Answers - The process in which producers make their own glucose
and produce water and carbon dioxide.
Photosynthesis Formula - Answers - CO2 + H20 -> C6H12O6 + O2
Biomass - Answers - The living mass of an organism(s).
It's dry mass.
Gross Primary Productivity - Answers - The total gain in energy/biomass per unit area
per unit time BY PRODUCERS.
Gross Secondary Productivity - Answers - The total gain in energy/biomass per unit
area per time BY CONSUMERS.
Net Productivity - Answers - The same thing as Gross Productivity, but after losses from
respiration.
