Since 1788, which group has experienced losses numbering over 9,000 species?

• A. Birds
• B. Mammals
• C. Fungi
• D. Invertebrates

Answer: (D)

The pattern here is about where biodiversity losses accumulate the most over long time periods. Invertebrates—the large group that includes insects, mollusks, crustaceans, worms, and others—make up the vast majority of Earth's species. Because there are so many of them and many have very small, specialized ranges, they are exceptionally vulnerable to changes like habitat loss, pollution, pesticides, climate shifts, and invasive species. That combination leads to a long record of extinctions, with numbers exceeding 9,000 for invertebrates since 1788. Birds and mammals, by contrast, have far fewer documented extinctions, partly because they’re better studied and often have larger, more protective ranges. Fungi face significant threats too, but their extinction records are harder to track due to gaps in taxonomy and monitoring. So, the group with the highest accumulated losses in this timeframe is invertebrates, reflecting both their enormous diversity and their particular vulnerability to rapid environmental change.