Indoor Air sciences CSMI Practice Exam

Which type of organism is established as saprobic in nature?

1. Photosynthetic algae

2. Fungi decomposing organic matter

3. Viruses infecting living cells

4. Pathogenic bacteria in soil

The correct answer is: Fungi decomposing organic matter

The classification of organisms as saprobic pertains to their role in the ecosystem, particularly how they obtain energy and nutrients from organic materials. Fungi are well-documented saprobes because they thrive on decomposing organic matter, breaking it down into simpler compounds. This process is vital for nutrient cycling within ecosystems, as it transforms dead organic material into forms usable by other organisms. Fungi release enzymes that digest complex organic substances, allowing them to absorb the smaller molecules. This decomposition not only provides food for the fungi but also enriches the soil and plays a crucial role in maintaining the health of the ecosystem. In contrast, the other options represent different ecological roles. Photosynthetic algae primarily produce their own food through photosynthesis rather than decomposing matter. Viruses, on the other hand, necessitate living cells for replication and cannot be classified as saprobic since they do not decompose organic matter. Similarly, pathogenic bacteria may cause harm to living organisms or contribute to the decomposition process but are not strictly classified as saprobes like fungi, which are specialized for breaking down organic materials.