Arthropods make up approximately what percent of all known animal species?

Arthropods make up approximately what percent of all known animal species?

• A. 50%
• B. 60%
• C. 75%
• D. 90%

Answer: (C)

Arthropods are the most species-rich group of animals, so the idea being tested is how much of animal biodiversity is accounted for by this group. Their success comes from a body plan that supports great diversification: an exoskeleton, segmented bodies, and many jointed limbs, plus the ability to occupy nearly every habitat. Insects alone make up a large share, and when you include all other arthropods—arachnids, crustaceans, myriapods—the total described species are distributed overwhelmingly toward this group. That cumulative dominance lands around three-quarters of all known animal species, or about 75%. So this option best reflects the real pattern of animal diversity. The other percentages would understate or overstate their share relative to how many species we’ve described.

Arthropods are the most species-rich group of animals, so the idea being tested is how much of animal biodiversity is accounted for by this group. Their success comes from a body plan that supports great diversification: an exoskeleton, segmented bodies, and many jointed limbs, plus the ability to occupy nearly every habitat. Insects alone make up a large share, and when you include all other arthropods—arachnids, crustaceans, myriapods—the total described species are distributed overwhelmingly toward this group. That cumulative dominance lands around three-quarters of all known animal species, or about 75%. So this option best reflects the real pattern of animal diversity. The other percentages would understate or overstate their share relative to how many species we’ve described.