Ontario Grade 9 Science Class Practice Exam 2026 - Free Grade 9 Science Practice Questions and Study Guide

An ecosystem is characterized by the interaction of living organisms, known as biotic factors, with their environment, which includes non-living components, known as abiotic factors. This concept reflects how both living things, such as plants and animals, and non-living elements like water, air, soil, and climate, play essential roles in sustaining the system as a whole. The interdependencies within an ecosystem are vital for processes such as nutrient cycling, energy flow, and habitat provision.

For instance, plants (biotic) rely on sunlight, water, and soil minerals (abiotic) to grow, while animals (biotic) depend on plants for food and oxygen. The combined interaction between these biotic and abiotic factors creates a balanced environment where living organisms can thrive, reproduce, and interact with each other. Understanding this interconnectedness is crucial in biology and ecology, as it helps explain the functioning and stability of natural systems.