The sign in Starbucks should read, "Friends are like snowflakes: more different and more beautiful each time you cross their paths in our common descent".
In science, one explains effects by citing causes, and that is exactly what is going on when one explains biological patterns in terms of common descent, natural selection, or some other from the suite of causes that are part of evolutionary theory.
One cannot compare the chemical structure of, say, an adenine nucleotide, ATP, NAD+, and coenzyme A and not recognize that these vital components of life may in fact be the result of common descent from a progenitor pool of organic molecules followed by divergence, nor that the startling similarity displayed represents actual molecular homology.
Some, along with widespread misunderstandings of evolutionary mechanisms such as natural selection, undoubtedly contribute to the staggeringly low public acceptance of the principle of common descent in North America (Alters and Nelson 2002; Miller et al. 2006).
This is not to say that no one at the time embraced the importance of variation, evolution, and common descent in understanding hereditary and infectious disease (e.g., Aitken 1885), and over time many scientists and physicians advocated the union of evolution and medicine (Huxley 1881; Aitken 1885; Richardson 1893; Morton 1926; Bynum 1983; Porter 1998; Zampieri 2009).
The percentage of genetic identity shared between any two individuals in the pedigrees through common descent was calculated for all possible pairs (related and unrelated) using S.A.G.E.
Further difficulty arises as families are defined quite legitimately in different ways: by common descent or by common possession of distinguishing features.
Although parasite taxonomic diversity and the measures of sampling effort might not be shared through common descent in birds, they may be correlated with other host characteristics that are inherited (e.g. body size).
To achieve the control for species-specific effects due to common descent in the interspecific context of DRB1*03, we applied the general method of phylogenetic analysis based on generalised least-squares (PGLS) models [ 80, 81] that incorporated primate phylogeny [ 42] and statistical weights.
In principle, due to the common descent of all living organisms, discoveries made in one species might provide scientists with valuable information about another species.
