Introduction To Evolution - Co-evolution

Co-evolution

Co-evolution is a process in which two or more species influence the evolution of each other. All organisms are influenced by life around them; however, in co-evolution there is evidence that genetically determined traits in each species directly resulted from the interaction between the two organisms.

An extensively documented case of co-evolution is the relationship between Pseudomyrmex, a type of ant, and the acacia, a plant that the ant uses for food and shelter. The relationship between the two is so intimate that it has led to the evolution of special structures and behaviors in both organisms. The ant defends the acacia against herbivores and clears the forest floor of the seeds from competing plants. In response, the plant has evolved swollen thorns that the ants use as shelter and special flower parts that the ants eat. Such co-evolution does not imply that the ants and the tree choose to behave in an altruistic manner. Rather, across a population small genetic changes in both ant and tree benefited each. The benefit gave a slightly higher chance of the characteristic being passed on to the next generation. Over time, successive mutations created the relationship we observe today.