Conservation of biodiversity connects biodiversity measurement, human-driven losses, ecosystem evidence, and targeted conservation strategies for protecting species, communities, and evolutionary history.
Biodiversity is the variety of life, measured at genetic, species and ecosystem levels.
Genetic diversity helps populations respond to change; species diversity describes richness and relative abundance; ecosystem diversity captures different habitats and ecological processes. A place can be rich at one level and poor at another. Use the evidence scale and context before drawing a broad conclusion.
State the level before measuring:
A forest may contain many species but little genetic diversity in a bottlenecked tree population, so one metric cannot describe all biodiversity.
Species count alone is not a complete biodiversity measure.
This objective is assessed through structured response, commonly using State / Discuss / Calculate.
State / Discuss / Calculate / Analyse / Compare / Evaluate / Distinguish / Suggest
Build the answer around this relationship: Biodiversity includes ecosystem diversity, species diversity and genetic diversity.
Equating richness with overall biodiversity when evenness also affects diversity.
Representative question
Entire communities need to be conserved in order to preserve biodiversity. Suggest different quantitative methods to measure changes in biodiversity in a community over time.
a. use transects/quadrats;
b. count number of species/individuals;
c. measure richness and evenness;
d. use Simpson (reciprocal) index;
e. indicator species/biotic index to reflect a specific environmental condition;
f. changes in Simpson index/richness/evenness/indicator species indicate changes in the community biodiversity;
4 max
Current biodiversity is the result of speciation, extinction, migration and environmental change, and it differs from biodiversity in the geological past.
Fossils and molecular evidence reveal earlier lineages, while modern surveys show present distributions. Comparisons depend on sampling, taxonomic definitions and the time scale chosen. Use the evidence scale and context before drawing a broad conclusion.
Compare past and present with care:
A fossil record can show that a marine group was once widespread even if only a few species survive today.
The fact that a species is absent from one modern survey does not prove global extinction.
Anthropogenic extinction occurs when human pressures reduce a species to zero surviving individuals across its natural range.
Habitat loss, overharvesting, invasive species, disease and climate change can reduce population size below recovery thresholds. Small populations then face inbreeding, demographic chance and further habitat loss. Use the evidence scale and context before drawing a broad conclusion.
Trace an extinction pathway:
Targeted hunting combined with slow reproduction can remove adults faster than a population replaces them, even when some habitat remains.
Local disappearance is extirpation; extinction means the species is gone globally.
This objective is assessed through multiple choice, commonly using Identify.
Identify
Build the answer around this relationship: Anthropogenic extinction is extinction caused by human activities.
Representative question
The North Island giant moa (Dinornis novaezealandiae) went extinct some time between the arrival of humans in New Zealand and the 1800s.
What do scientists believe to be the cause of this extinction?
Deforestation
New diseases
Competition with other megafauna
Overhunting
D
Ecosystem loss occurs when habitat area, structure or function is reduced by direct land-use change or indirect environmental pressures.
Deforestation, drainage, fragmentation and development remove or divide habitat. Pollution, altered fire regimes, invasive species and climate change can then degrade what remains and disrupt flows of energy and nutrients. Use the evidence scale and context before drawing a broad conclusion.
Identify the causal chain:
A road can remove a strip of forest and also isolate populations, increase edge heat and introduce invasive species.
Protecting the remaining area alone may not restore function if indirect pressures continue.
This objective is assessed through multiple choice, structured response, commonly using Outline / Explain / Describe.
Outline / Explain / Describe / Suggest
Build the answer around this relationship: Deforestation reduces biodiversity by removing habitat and essential resources.
Naming deforestation without explaining loss of habitat, food, shelter or breeding sites.
Representative question
The satellite images show changes in the area covered by forest, much of which is mixed dipterocarp forest, on the island of Borneo in Southeast Asia.
Which human activities are most likely to have caused the changes shown in the map?
Logging and palm oil plantation
Logging and rewilding
Mining and afforestation
Afforestation and palm oil plantation
A
Evidence for a biodiversity crisis comes from consistent trends in abundance, range, extinction risk, genetic diversity and ecosystem integrity.
Long-term monitoring, museum records, remote sensing and standardized surveys can distinguish real declines from changing detection effort. Multiple indicators are stronger than one dramatic case. Use the evidence scale and context before drawing a broad conclusion.
Evaluate a trend by checking:
A repeated decline in standardized bird counts across many sites is stronger evidence than one year of observations from a single park.
A crisis claim should report scale and uncertainty rather than imply every species is declining equally.
The biodiversity crisis is caused by interacting pressures such as habitat change, overexploitation, invasive species, pollution and climate change.
Drivers can combine: fragmentation makes populations more vulnerable to warming, while pollution and invasive predators add stress. Interactions can produce faster decline than any one pressure alone. Use the evidence scale and context before drawing a broad conclusion.
Separate primary drivers from mechanisms:
A reef may lose corals through warming, acidification and disease together, so reducing one pressure may not restore it alone.
Listing threats is not enough; explain how they act and interact on the population or ecosystem.
This objective is assessed through structured response, commonly using Outline / State.
Outline / State
Build the answer around this relationship: Urbanization and agricultural land clearance reduce habitat and fragment ecosystems.
Representative question
List human actions that could threaten populations of insect pollinators such as bees.
a. use of pesticides/insecticides (which may kill/harm pollinators);
b. urbanization;
c. loss of habitat/change of land use (monocultural/intensive farming practices);
d. use of herbicide or removal of "weeds" reducing food sources;
e. introduction of alien species;
For a. or d. the mention of a specific pesticide or herbicide would be ok.
3
Marking guidance:
max
Conservation can protect habitats, manage populations, restore ecosystems and reduce the pressures causing decline.
In-situ reserves protect ecological processes; ex-situ breeding can preserve genetic material; restoration and sustainable-use rules address damaged or harvested systems. Effective plans monitor outcomes and adapt actions. Use the evidence scale and context before drawing a broad conclusion.
Choose a strategy by asking:
A threatened amphibian may need habitat protection, disease control and a carefully managed captive-breeding release rather than one action alone.
A reserve without enforcement or connectivity may protect a boundary on a map but not the population’s survival.
This objective is assessed through essay response, structured response, commonly using Discuss / Outline / Distinguish.
Discuss / Outline / Distinguish / Explain / Suggest
Build the answer around this relationship: In situ conservation protects species within their natural habitats and communities.
Defining in situ and ex situ without linking each approach to its conservation advantages and limits.
Representative question
Discuss in situ and ex situ conservation of endangered species.
a. both methods ensure continuing survival of species/recover endangered species;
b. in situ (conservation) occurs in natural habitat;
c. ex situ (conservation) takes place outside original/natural habitat/occurs in artificial/controlled habitat;
d. in situ not as disruptive;
e. in situ encourages conservation of natural habitat;
f. ex situ may be last chance for survival / increase breeding
OR
needed if species too rare to be left in the wild;
g. one example of either type of conservation;
Marking guidance:
Max 3 marks if only in situ or ex situ discussed;
Or converse for marking points d and e
4 max
The EDGE of Existence approach prioritizes species that are both evolutionarily distinct and globally endangered.
Evolutionary distinctiveness estimates how much unique evolutionary history a species represents; global-endangerment status estimates extinction risk. Combining them directs limited conservation resources toward irreplaceable branches and urgent threats. Use the evidence scale and context before drawing a broad conclusion.
Interpret an EDGE priority:
Protecting a highly distinct, critically endangered mammal can preserve more unique evolutionary history than protecting a common close relative.
EDGE ranking does not mean other species have no value; it is a prioritization tool under limited resources.
This objective is assessed through structured response, multiple choice, commonly using Outline / Describe.
Outline / Describe
Build the answer around this relationship: EDGE species are both evolutionarily distinct and globally endangered.
Explaining EDGE only by expanding the initials without linking distinctiveness to extinction risk.
Representative question
Outline the importance of the EDGE of Existence programme.
a. estimates the expected loss of evolutionary history (per unit time) / helps maintain the evolutionary history
OR
focuses on species that belong to small clades (few or no close relatives);
b. focuses on species with populations in danger of extinction;
c. conservation actions can be taken for EDGE species
OR
EDGE lists inform/inspire/suggest priorities for conservation;
Marking guidance:
Do not award marking points for just repeating what ED and GE stand for.
2
max
A strong conservation answer follows a chain: define biodiversity, measure evidence of decline, identify human drivers, then justify conservation action. Biodiversity includes ecosystem, species, and genetic diversity; species diversity uses richness and evenness. Evidence comes from estimates, fossils, repeated surveys, IPBES reports, and indices. Drivers include extinction pressure, ecosystem conversion, population-driven resource demand, pollution, and invasive species. Responses include in situ, ex situ, and EDGE prioritization.