Different evolutionary lines that encounter extremely similar forces of natural election tend to become more similar as they evolve. This is known as

convergent evolution

Explanation:

Convergent evolution is the evolutionary process by which independent species evolve similar phenotypic traits as a consequence of the adaptation to similar environmental conditions and/or ecological niches. A well-known example of convergent evolution are the wings of birds, insects and bats that evolved separately in these different lineages. Convergent evolution is opposite to divergent evolution in which closely related organisms evolve different phenotypic traits (for example, Darwin's finches, which are closely related species that have both similar and different traits).

when a reversible reaction is occurring in both directions at the same rate; the products and reactants do not change in concentration. a chemical reaction where the compound is broken into its constituent parts.