WHy is it important to consider only homologous characters in reconstructing phylogenetic trees? Thank You.
Because analogous traits have no relation to each other, they are simply traits that 2 different species have evolved due to similar selective pressures. For instance, a sea urchin vs. a cactus, they both share this spiky spine trait, however they do not share a common ancestor, we cannot build a phylogenetic tree with this information.
We can with homologous traits because they are derived from a common ancestor.