Rather, common ancestry is supported by morphological (typological) genetic, and temporal evidence.
It's actually well-known that there is considerable incongruence between various morphological trees and genetic trees. And genetic trees don't always resolve an ancestral relationship either because the different loci within the same species often show incongruence. 100% congruence is rarely found.
There are several reasons for this. Homoplasy and recombination make resolution sometimes very difficult. Plus, the correspondence between genotype and phenotype is rarely one to one. What's more, tree construction is based on data sets with varying ratios of signal to noise. One can imagine that morphological data sets are incomplete and very noisy, yet, the classic trees were constructed with them.
There are some examples where the genetic data has turned the morphological relationships completely on their heads.
Here are a just few references out of the many hits on a search for discordance/incongruence-morphological-genetic/phylogenetic incongruence, etc.
Syst Biol 1999 Dec;48(4):683-714
Data set incongruence and correlated character evolution: an example of functional convergence in the hind-limbs of stifftail diving ducks.
McCracken KG, Harshman J, McClellan DA, Afton AD.
Proc Natl Acad Sci U S A. 1994 Oct 11;91(21):9861-5.
Molecules vs. morphology in avian evolution: the case of the "pelecaniform" birds.
Hedges SB, Sibley CG.
To be sure, this doesn't turn common ancestry on its head, but it is important to remember that in biology, things are never very clean.
Yes, indeed! I never studied biology to any great depth, but enough that this much became clear. Thanks for the info.
Creationists (I wish there was a separate and single word to distinguish the mulishly antievolutionary sort from simple believers in the docrine of Creation) place great emphasis on the complexity of biological organisms, but then in respect to certain lines of argument (and also as a more general tendency it seems) will treat of biological phenomena as though they should express the simplicity of gear driven clockwork.