How is biodiversity described and why does it matter to human wellbeing?
the levels of biodiversity (genetic, species and ecosystem) and the value of biodiversity through ecosystem services and human wellbeing
A focused answer to the VCE Environmental Science Unit 3 dot point on the three levels of biodiversity and the value of biodiversity through ecosystem services and human wellbeing, with Australian examples.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
What this dot point is asking
VCAA wants you to describe biodiversity at three nested levels and to explain why it matters by linking it to ecosystem services and human wellbeing. You should be able to define each term, give Australian examples, and explain how losing biodiversity reduces the services people depend on.
The three levels of biodiversity
Biodiversity is the variety of life at all levels of biological organisation. It is measured at three levels.
Genetic diversity is the variety of alleles (gene versions) within a species. High genetic diversity means a population can adapt to change (drought, disease, new predators) because some individuals carry useful alleles. Low diversity makes a population vulnerable. The remaining population of the Tasmanian devil has low genetic diversity, which is one reason Devil Facial Tumour Disease has spread so readily, as many individuals share similar immune genes.
Species diversity is the variety of species in an area. It has two components: richness (the number of different species) and evenness (how equally individuals are spread among those species). A patch of Victorian box-ironbark forest with 40 bird species shared fairly evenly is more diverse than one dominated by a single introduced species.
Ecosystem diversity is the variety of habitats, communities and ecological processes across a region. Australia ranges from the Great Barrier Reef and tropical rainforest to alpine bogs, mallee and arid spinifex grassland. This variety of ecosystems supports the variety of species and genes within them.
These levels are nested: genetic diversity sits within species, and species sit within ecosystems. Damage at one level flows through to the others.
Ecosystem services: why biodiversity is valued
Ecosystem services are the benefits that humans gain from functioning ecosystems. The Millennium Ecosystem Assessment groups them into four categories.
Supporting services are the basic processes that make all other services possible: soil formation, nutrient cycling, photosynthesis and primary production. Without these, no food or clean water is possible.
Provisioning services are tangible products: food, fresh water, timber, fibre, and genetic resources for medicine and crops. Murray-Darling Basin wetlands provision irrigation water and fisheries.
Regulating services are the benefits from regulation of ecosystem processes: climate regulation (carbon storage in forests and seagrass), flood control by mangroves and wetlands, water purification, and pollination. Australian native bees and other insects pollinate crops worth hundreds of millions of dollars each year.
Cultural services are non-material benefits: recreation, tourism, aesthetic value, and spiritual and cultural significance. The Great Barrier Reef and Uluru-Kata Tjuta hold deep cultural value for Aboriginal Traditional Owners and support a large tourism economy.
Biodiversity and human wellbeing
Human wellbeing has several dimensions: the basic materials for a good life (food, shelter), health, security, good social relations, and freedom of choice. Each draws on ecosystem services and therefore on biodiversity.
When biodiversity declines, services degrade. Clearing native vegetation in Western Australia's wheatbelt raised water tables and brought salt to the surface (dryland salinity), reducing the provisioning service of productive farmland. Bleaching events on the Great Barrier Reef reduce both the regulating service of coastal protection and the cultural and economic service of tourism. Protecting biodiversity is therefore not separate from human interests: it is the foundation of the services that sustain people.
Intrinsic versus instrumental value
Biodiversity also has intrinsic value (worth in its own right, independent of usefulness to humans) as well as instrumental value (usefulness as a resource or service). Many conservation arguments combine both: a species may be protected because it provides pollination (instrumental) and because it has a right to exist (intrinsic).
Exam-style practice questions
Practice questions written in the style of VCAA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
2025 VCAA3 marksA group of Environmental Science students measured the species diversity at their local park, finding both exotic and native species in a quadrat. Explain the difference between species richness and relative abundance with reference to the students' data.Show worked answer →
A 3 mark answer defines both terms and applies each to the data.
1 mark: species richness is the number of different species present in the sample. In the students' data there were five species (tussock grass, bearded oatgrass, rough spear grass, housefly and ant), so the species richness is 5.
1 mark: relative abundance is the proportion (or relative number) of individuals belonging to each species, that is, how common each species is compared with the others.
1 mark: apply it to the data. The exotic separated tussock grass (25 of 34 individuals) has by far the highest relative abundance and dominates the sample, while species such as the oatgrass, housefly and ant each have very low relative abundance. So although richness is 5, the community is uneven because one species dominates.
2025 VCAA3 marksThe southern pygmy perch was reintroduced to Bendigo Creek in 2020. Conservationists performed genetic analysis of the population in 2022. Explain why the conservationists were interested in measuring the genetic diversity of the perch population after the reintroduction program.Show worked answer →
A 3 mark answer connects genetic diversity to the success and resilience of the reintroduced population.
1 mark: genetic diversity is the variety of alleles (gene versions) within the population.
1 mark: a reintroduction often starts from a small number of founder individuals, so the new population can have low genetic diversity and a risk of inbreeding, which raises the chance of genetic disease and reduces fitness.
1 mark: measuring genetic diversity tells conservationists whether the population has enough variation to adapt to change (disease, drought, predators) and remain viable in the long term. Low diversity would signal a need for further intervention, such as introducing individuals from other populations to boost the gene pool.