Which term describes a non-native species that can cause ecological harm?

• A. Keystone species
• B. Invasive species
• C. Heredity
• D. Pioneer species

Answer: (B)

Non-native species that cause ecological harm are invasive species. The defining idea is that while many non-native organisms exist, invasives spread aggressively and disrupt native ecosystems, outcompeting local species for resources, altering habitats, and sometimes bringing new diseases or predators. This distinguishes them from other terms: a keystone species is one that has a disproportionately large effect on its environment, but not necessarily because it is non-native or harmful; pioneer species are the first organisms to colonize a disturbed area and usually help start recovery; heredity refers to genetic inheritance, not ecological impact. So the best fit for a non-native organism that harms ecosystems is invasive species.