What type of organisms primarily contribute to photosynthesis in an ecosystem?

Plants are the primary contributors to photosynthesis in an ecosystem because they contain chlorophyll, a pigment that captures sunlight. Through the process of photosynthesis, plants convert carbon dioxide and water into glucose and oxygen, using sunlight as the energy source. This process not only provides food for the plants themselves but also serves as the fundamental source of energy for other organisms within the ecosystem, from herbivores that consume the plants to carnivores that feed on those herbivores.

While certain bacteria and protists can also perform photosynthesis, such as cyanobacteria and some phytoplankton, the major role in terrestrial ecosystems is played by plants. Animals, on the other hand, are consumers that depend on either plants or other animals for their energy and nutrients, thus do not contribute directly to photosynthesis. Therefore, plants are recognized as the primary autotrophs in ecosystems, playing a crucial role in energy flow and nutrient cycling.