What is an ecosystem?

An ecosystem is best defined as a community of living organisms interacting with their physical environment. This definition captures the dynamic relationships between biotic factors, such as plants, animals, and microorganisms, and abiotic factors, including air, water, soil, and climate. These interactions create a complex web of life where organisms depend on each other and their environment for survival and reproduction.

In an ecosystem, energy flow and nutrient cycles are governed by these interactions, making it more than just a simple pathway of energy transfer. For instance, plants (producers) convert sunlight into energy through photosynthesis, which is then passed on to herbivores (primary consumers) and subsequently to carnivores (secondary consumers). This intricate network highlights the importance of both biotic and abiotic components working together.

Other definitions, such as a linear sequence of energy flow or simply a group of species, do not encompass the full complexity of interactions and relationships that define an ecosystem. While a habitat and its abiotic factors are parts of an ecosystem, they alone do not complete the definition without considering the living organisms and their interactions with each other and the physical environment. Thus, the holistic nature of the interactions that define an ecosystem makes this choice the most accurate representation of the concept.