Which two human activities are commonly cited as altering ecosystem dynamics, potentially reducing biodiversity and disrupting energy flow?

• A. Pollution and habitat destruction
• B. Seasonal changes and natural disturbances
• C. Predator introductions and migration
• D. Volcanic eruptions and earthquakes

Answer: (A)

Human activities that disrupt ecosystems typically alter how energy moves through the system and reduce the variety of life. Pollution introduces toxins, nutrient overloads, and other stressors that can suppress primary producers, harm wildlife, and create low-oxygen dead zones; with fewer producers and stressed populations, less energy enters and moves up the food web, making energy transfer less efficient and the ecosystem less stable. Habitat destruction, such as clearing land, urban development, or fragmentation, removes or isolates habitats, shrinking the number of species and disrupting interactions like predation and pollination. When biodiversity declines and interactions change, the pathways through which energy flows are altered, often weakening the overall structure of the ecosystem. These two human actions are frequently cited because they directly influence both the amount of energy available at different levels and the diversity of organisms that help transfer that energy. The other options describe natural processes or scenarios that are not as consistently linked to broad, long-term changes in biodiversity and energy flow.