Читать книгу Principles of Microbial Diversity - James W. Brown - Страница 28

So, all organisms are mostly the same. What does this mean? Primarily, it means that all organisms share a common ancestry. In other words, all known organisms can trace their history back to a single origin of life. This might not have been the case; other lineages, if they ever existed, seem to be extinct (or perhaps undiscovered or unrecognized?).

The fact that all organisms are very much alike also means that the last common ancestor of all known living things was a complex organism or population of organisms. Most of biochemical evolution predates the last common ancestor. The last common ancestor had all of the biochemistry that is now universal, which means nearly everything. Biochemical evolution occurred very early in the emergence of life. The diversity in extant life (known modern life) is in peripheral biochemistry—just the details!