rationalskepticism.org

Wortfish wrote:

Rumraket wrote:

Calilasseia wrote:Wrong. It does imply universal common descent, courtesy of the fact that current populations inherited their genetic constitution from relevant ancestors.

No c'mon. The fact that macroevolution is a fact, as in we know that speciation happens and that species can radically change morphology and biochemistry through evolutionary change on geological time-spans, does not itself imply that all species currently known must share a common genealogical realationship.

There is evidence that they do, but the mere definition of the term macroevolution isn't evidence for anything. Macroevolution could be true, while universal common descent could be false. There could concievably have been multiple independent origins of life, and different parts of extant biodiversity could in such a scenario trace their ancestry to independent origins. We could at least in principle have two parallel trees of life, or even more.

In other words, life could be polyphyletyic rather than monophyletic.

Here we commence to beat Pauling's poor 40-year dead horse. If there is one historical phylogenetic tree which unites all species in an objective genealogy, all separate lines of evidence should converge on the same tree (Penny et al. 1982; Penny et al. 1991; Zuckerkandl and Pauling 1965). Independently derived phylogenetic trees of all organisms should match each other with a high degree of statistical significance.
(...)
So, how well do phylogenetic trees from morphological studies match the trees made from independent molecular studies? There are over 1038 different possible ways to arrange the 30 major taxa represented in Figure 1 into a phylogenetic tree (see Table 1.3.1; Felsenstein 1982; Li 1997, p. 102). In spite of these odds, the relationships given in Figure 1, as determined from morphological characters, are completely congruent with the relationships determined independently from cytochrome c molecular studies (for consensus phylogenies from pre-molecular studies see Carter 1954, Figure 1, p. 13; Dodson 1960, Figures 43, p. 125, and Figure 50, p. 150; Osborn 1918, Figure 42, p. 161; Haeckel 1898, p. 55; Gregory 1951, Fig. opposite title page; for phylogenies from the early cytochrome c studies see McLaughlin and Dayhoff 1973; Dickerson and Timkovich 1975, pp. 438-439). Speaking quantitatively, independent morphological and molecular measurements such as these have determined the standard phylogenetic tree, as shown in Figure 1, to better than 38 decimal places. This phenomenal corroboration of universal common descent is referred to as the "twin nested hierarchy". This term is something of a misnomer, however, since there are in reality multiple nested hierarchies, independently determined from many sources of data.

... However, as illustrated in Figure 1, the standard phylogenetic tree is known to 38 decimal places, which is a much greater precision than that of even the most well-determined physical constants. For comparison, the charge of the electron is known to only seven decimal places, the Planck constant is known to only eight decimal places, the mass of the neutron, proton, and electron are all known to only nine decimal places, and the universal gravitational constant has been determined to only three decimal places.