Habitats are smaller areas like a wood or a rocky beach. An organisms niche is all the information required to define its place in its habitat. The transfer of energy and nutrients through a series of organisms is known as a food chain. Each stage is a trophic level. These are consumed by herbivores and then carnivores.
Producers can vary in size, e.g. an oak tree.
Range of numbers is often too great for graph paper. Seasonal changes, e.g. organisms in a lake. Biomass Produce a better picture but are time consuming and involve killing the organism. Measures the standing crop not the productivity. A problem with small organisms with a short life cycle.