Cows and birds cooperate to increase survival
Cow with attendant white egrets. Getty/Craig Pershouse

Symbiogenesis is an evolution term that relates to the cooperation between species in order to increase their survival.

The crux of the theory of natural selection, as laid out by the “Father of Evolution” Charles Darwin, is competition. Mostly, he focused on competition between individuals of a population within the same species for survival. Those with the most favorable adaptations could compete better for things like food, shelter, and mates with which to reproduce and make the next generation of offspring that would carry those traits in their DNA.

Darwinism relies on competition for these sorts of resources in order for natural selection to work. Without competition, all individuals would be able to survive and the favorable adaptations will never be selected for by pressures within the environment.

This sort of competition can also be applied to the idea of coevolution of species. The usual example of coevolution typically deals with a predator and prey relationship. As the prey get faster and run away from the predator, natural selection will kick in and select an adaptation that is more favorable to the predator. These adaptations could be the predators becoming faster themselves to keep up with the prey, or maybe the traits that would be more favorable would have to do with the predators becoming stealthier so they can better stalk and ambush their prey. Competition with other individuals of that species for the food will drive the rate of this evolution.

However, other evolutionary scientists assert that it is actually cooperation between individuals and not always competition that drives evolution. This hypothesis is known as symbiogenesis. Breaking down the word symbiogenesis into parts gives a clue as to the meaning. The prefix sym means to bring together.

Bio of course means life and genesis is to create or to produce. Therefore, we can conclude that symbiogenesis means to bring individuals together in order to create life. This would rely on cooperation of individuals instead of competition to drive natural selection and ultimately the rate of evolution.

Perhaps the best known example of symbiogenesis is the similarly named Endosymbiotic Theory popularized by evolutionary scientist Lynn Margulis. This explanation of how eukaryotic cells evolved from prokaryotic cells is the currently accepted theory in science. Instead of competition, various prokaryotic organisms worked together to create a more stable life for all involved. A larger prokaryote engulfed smaller prokaryotes that became what we now know as various important organelles within a eukaryotic cell. Prokaryotes similar to cyanobacteria became the chloroplast in photosynthetic organisms and other prokaryotes would go on to become mitochondria where ATP energy is produced in the eukaryotic cell. This cooperation drove the evolution of eukaryotes through cooperation and not competition.

It is most likely a combination of both competition and cooperation that fully drive the rate of evolution through natural selection.

While some species, such as humans, can cooperate to make life easier for the entire species so it can thrive and survive, others, such as different types of non-colonial bacteria, go it on their own and only compete with other individuals for survival. Social evolution plays a large part in deciding whether or not cooperation will work for a group which would in turn reduce the competition between individuals. However, species will continue to change over time via natural selection no matter if it is through cooperation or competition. Understanding why different individuals within species choose one or the other as their primary way of operating may help deepen the knowledge of evolution and how it occurs over long periods of time.