Every scientific investigation is grounded in specific environmental science concepts. Clearly defining key terms and demonstrating conceptual understanding is expected in both investigation reports and VCAA examination responses.
| Term | Definition |
|---|---|
| Biodiversity | Variability among living organisms at genetic, species and ecosystem levels |
| Species richness | Total number of species in a defined area |
| Species evenness | Relative abundance distribution of species |
| Simpson’s Index of Diversity (SID) | Combined measure of richness and evenness: \$1 - \frac{\sum n_i(n_i-1)}{N(N-1)}$ |
| Endemism | Proportion of species found nowhere else |
| Ecosystem | A community of living organisms interacting with each other and their physical environment |
| Habitat | The environment in which a species lives — characterised by physical features |
| Keystone species | A species whose impact on its ecosystem is disproportionately large relative to its abundance |
| Ecological succession | Sequential change in species composition following disturbance |
| Term | Definition |
|---|---|
| Sustainability | Using resources at a rate that allows natural systems to continue replenishing them |
| Ecological integrity | The capacity of an ecosystem to maintain its structure, function and self-organising capacity |
| Threatening process | An activity, event or process that threatens the survival of a species or ecological community |
| Ecosystem service | A benefit provided by an ecosystem to human well-being |
| Adaptive management | A management framework that builds monitoring and learning into the management cycle |
| Term | Definition |
|---|---|
| Enhanced greenhouse effect | The additional warming of Earth’s surface due to human-increased GHG concentrations |
| Greenhouse warming potential (GWP) | Measure of the infrared energy a gas absorbs relative to CO$_2$ over a specified period |
| Carbon sequestration | The capture and long-term storage of atmospheric CO$_2$ |
| Phenology | The study of cyclic and seasonal natural phenomena, including timing of biological events |
| Climate forcing | A factor that alters the balance between incoming solar radiation and outgoing infrared radiation |
| Term | Definition |
|---|---|
| Energy efficiency | Ratio of useful energy output to total energy input |
| Renewable energy | Energy from sources that are naturally replenished on human timescales |
| Base load | Minimum level of electricity demand over a 24-hour period |
| Peak load | Highest level of electricity demand, typically of short duration |
| Embodied energy | Total energy required to produce, transport and install a product |
| EROI (Energy Return on Investment) | Ratio of energy produced to energy consumed in extraction |
For your own investigation, clearly define:
1. The environmental system being studied (ecosystem, species, climate zone, energy system)
2. The variables being measured (operational definition — how will each be measured in practice?)
3. Any indices or calculations used (give the formula)
4. The spatial and temporal scale of investigation (what area? over what time period?)
Example for a revegetation study:
- Define ‘revegetated area’ as ‘land that has been planted with native species for at least 2 years’
- Define ‘reference area’ as ‘adjacent native vegetation of the same ecosystem type undisturbed for >50 years’
- Define ‘species diversity’ using SID with the formula
- Define ‘sampling unit’ as a 10×10 m quadrat randomly placed within each zone
VCAA FOCUS: Investigation report criteria specifically assess whether students define key concepts accurately and use scientific terminology correctly. Abstract or incomplete definitions score poorly. Always link your concepts to the specific investigation — general textbook definitions are insufficient without connection to how you measured or applied them.
