3 ms·

Why would anyone expect “trees” to be monophyletic?

• da39a3ee 5y ago
  I'm sorry, I should have explained the jargon here. A "monophyletic" set of organisms is defined to be a set for which there exists a common ancestor, which ancestor has no descendents outside the set. (Try to ignore sexual reproduction when thinking about that; think about "lineages" of "species" first.) This concept is the basis of modern biological taxonomy. A "tree" is a plant with very pronounced woody structures. There is nothing about the botanical concept of a "tree" that immediately suggests they should be monophyletic. At least to someone with general biological knowledge, it would seem entirely possible that this woody morphological form could have arisen multiple times independently, and indeed that is what one would suspect, given knowledge of the prevalence of convergent evolution elsewhere.