Urban Economics: How Cities Drive Economic Development

Symbiosis and mutualism seem to be the fundamental forms of interaction in nature, which mostly acted through the course of evolution to shape the fate of species. Symbiosis is defined as the close and usually long-term relationship between different biological species, while mutualism is a certain type of symbiosis in which both the partners benefit. These interactions are very important for the survival and thriving of many organisms that they have dominated the evolutionary trajectories of innumerable species.

Mutualistic relationships are to be found in all types of ecosystems. A classical example is flowering plants with their pollinators: bees, birds, and bats. Plants offer nectar and pollen as food, while the pollinators aid in plant reproduction by carrying the pollen from one bloom to another. Mutualistic interactions, such as the one between plants and pollinators, have driven coevolution between them, resulting in species diversification and the evolution of specialized structures and behaviors.

Another example is the symbiosis involving some fungi and the roots of plants: the mycorrhizae. Fungi enhance the absorption of water and other essential nutrients, mainly phosphorus, :wq from the soil to plants, while plants, in return, provide the fungi with carbohydrates produced photosynthetically. This mutualism enables an increase in plant growth and resistance, thus adding to ecosystem stability and productivity.

Symbiosis is also more directly critical to the evolution of more complex life forms because of mutualism. For example, in both ancient prokaryotic cells, it is currently believed that their evolution into much larger, far more complex eukaryotic cells involved some kind of symbiotic relationship. It is likely that, indeed, the little organelles within eukaryotic cells that actually produce energy-mitochondria-evolved from some kind of symbiosis between the ancient eukaryote and some bacterium. This sort of turnover in cellular complexity would eventually enable the further evolution of multicellular organisms.