Answer:
1. Changes in energy flow and chemical cycle can affect the productivity of the ecosystem.
2. Disturbance is a key feature of the community because it is the disturbance that produces diversity within the community.
3. A niche is the combination of an organism’s habitat, its adaptations and its role in the habitat. In the absence of competition from other species an organism can occupy its range and it is called fundamental niche. Due to competition its niche narrows and the narrowed down niche is called realized niche.
4. In its niche Chthamalus, a type of barnacle has to face competition from Balanus which is also a barnacle. Thus the realized niche of Chthamalus is the high tide zone. In the absence of competition from Balanus whole of the inter-tidal zone is the niche of Chthamalus which is its fundamental niche.
5. Species richness decreases on moving from lower latitudes to higher latitudes. Species richness is more near the equator and on moving towards the poles it decreases.