Question

Explain why a phylogeny is a hypothesis

Answer 1

Technically, the term 'phylogeny' refers to the evolutionary history of a group of organisms. The terms 'phylogenetic tree' and 'evolutionary tree' are equivalent and refer to the tree-like structures that represent our hypotheses about that evolutionary history.

A phylogenetic tree is a hypothesis about evolutionary relationships. The location and order of evolutionary history has unfolded. As with any other hypothesis, these hypothesis are tests: When new evidence is obtained we test our current phylogenetic trees, or our current inferences about evolutionary events, against this new evidence to see whether our previous hypotheses are consistent with the new findings. If so, the phylogenetic trees that we have constructed remain our working hypothesis; if they aren’t, we reevaluate and modify the tree given our new evidence. Allof science operates in this fashion, and the study of phylogeny, while focused on past events, is no different.