Conservation of biodiversity practice questions.

State which measure best combines both the number of species and the relative abundance (evenness) of individuals in a community.

• Species richness
• Simpson's index
• Population density
• Carrying capacity

Answer: Simpson's index

Richness counts only how many species are present; a diversity index such as Simpson's reflects both richness and the evenness of abundance among those species.

A conservation biologist aims to protect the widest range of distinct evolutionary lineages in a region. Which level of biodiversity does this aim target?

• Habitat diversity only
• Genetic diversity within one population
• Species diversity across ecosystems
• Diversity of abiotic factors

Answer: Species diversity across ecosystems

Protecting the greatest range of distinct evolutionary lineages is best served by conserving species diversity across ecosystems, which captures the widest variety of organisms.

Two woodlands each contain 100 individuals split among 5 species. Wood X has 96,1,1,1,1; Wood Y has 20,20,20,20,20. Determine which statement is correct.

• Both have identical biodiversity because richness is equal
• Wood Y has higher diversity because it is more even
• Wood X has higher diversity because one species dominates
• Evenness has no effect on a diversity index

Answer: Wood Y has higher diversity because it is more even

Richness is equal (5 species), but Wood Y is far more even, so a diversity index such as Simpson's gives it the higher value.

Outline which of the following is an example of in-situ conservation.

• A captive breeding programme in a zoo
• A seed bank storing dried seeds
• A national park protecting a habitat
• A botanic garden growing rare plants

Answer: A national park protecting a habitat

In-situ conservation protects organisms within their natural habitat; national parks and nature reserves are the classic example, whereas zoos, seed banks and botanic gardens are ex-situ.

Suggest the most likely direct cause of the recent sharp rise in the global rate of species extinction.

• Natural background extinction alone
• Habitat loss and overexploitation
• Continental drift over millions of years
• Reduced volcanic activity

Answer: Habitat loss and overexploitation

The current elevated extinction rate is driven mainly by human activities: habitat loss, overexploitation, pollution, invasive species and climate change, far exceeding the natural background rate.

Explain why an introduced (invasive) species can reduce biodiversity in a new ecosystem.

• It always increases the number of trophic levels
• It outcompetes or preys on native species
• It immediately hybridises with all native species
• It only affects abiotic factors, not organisms

Answer: It outcompetes or preys on native species

Invasive species often lack natural predators and can outcompete or prey on native species that have not co-evolved defences, driving local extinctions and lowering diversity.