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Interactions within Ecosystems Cheat Sheet (DRAFT) by

Living organisms interact with the environment in order to survive. The study of various relationships between living organisms and its environment is known as ecology

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Physical Factors

Physical Factor
How it affects living Organisms
Water
● Crucial for any organisms’ survival ● More organisms are usually present in locations where water is readily available
Air
● Plants need carbon dioxide from the air to photos­ynt­hesise
Light
● Green plants use light to make food via photos­ynt­hesis ● Most animals use light to see and aid movement for finding food and escaping danger
Temperature
● Affects the activities and functi­oning of organisms
Minerals
● Minerals are compounds containing elements essential for healthy growth e.g. nitrogen, phosphorus and potassium ● Used to make key substances e.g. chloro­phyll, proteins and vitamins
Acidity­/Al­kal­inity (pH)
● Most organisms cannot survive in enviro­nments that are too acidic or too alkaline

Types of Adapta­tions

Type of Adaptation
Definition
Structural
Physical features of organisms to help it survive
Behavi­oural
Ways organism act in order to survive

Levels of Organi­sation

Level (simplest to most complex)
Definition
Organism
Individual living thing
Population
A group of organisms of the same species living together in a particular habitat
Community
A group of popula­tions that live and interact with one another in a particular habitat
Ecosystem
A community of organisms intera­cting with one another and the abiotic enviro­nment
Biosphere
The part of Earth that contains all ecosys­tems. It interacts with the atmosp­here, hydros­phere and lithos­phere.
 

Relati­onships between Organisms

Relati­onship (most to least harmful)
Definition
Predat­or-prey
An organism (predator) feeds on another organism (prey)
Parasi­te-host
An organism (parasite) depends on another organism (host) for food, harming it and possibly killing it
Commen­salism
Relati­onship between 2 organisms in which one organism benefits without harming the other
Mutualism
Relati­onship between 2 organisms in which both organisms benefit

Energy flow

Property
Definition
Direction
Energy flows in one direction in a food chain
Energy transfer
(10%) Energy is transf­erred to the next trophic level
Energy lost
(90%) Energy is utilised by the organism for cellular proces­ses­/lost as heat (from respir­ation), waste products (excretion and egestion) and uneaten parts

Obtaining Energy (Nutrient Cycles)

Method
Definition
Respir­ation
Refers to living organisms breaking down food consumed to release energy
Respir­ation Word Equation
Glucose + Oxygen → Carbon dioxide + Water + energy

Releasing Energy (Nutrient Cycles)

Method
Definition
Photos­ynt­hesis
○ Plants containing chloro­phyll will absorb carbon dioxide to manufa­cture food in the presence of light ○ Word equation: Carbon dioxide + Water + Light energy → Glucose + Oxygen
Decomp­osers
Organism that feed on and break down dead matter into simpler substances that is returned to the enviro­nment
Scavengers
Animals that feed on and break up dead organisms into smaller pieces­Animals that feed on and break up dead organisms into smaller pieces