What is a contributing reason that Australia’s biodiversity is highly vulnerable to modern ecological threats?

• A. Long isolation of species evolution
• B. High rainfall
• C. Flat terrain
• D. Intense predation by birds

Answer: (A)

Long isolation of species evolution means Australia developed a fauna with many unique, highly specialized organisms that occupy narrow ecological niches and have restricted ranges. When species evolve in isolation, they encounter fewer predators, diseases, and competing species that are common elsewhere, so they often lack defenses against threats that come with globalization—such as invasive predators (cats, foxes), new pathogens, and rapid habitat and climate changes. This makes populations small and vulnerable, with limited genetic diversity to adapt quickly, so modern threats can cause sharp declines or extinctions. The other factors listed don’t capture why Australia’s biodiversity is so at risk on a global scale; rainfall, terrain, or bird predation aren’t the fundamental drivers of this particular vulnerability.