The Evolutionist Phylogeneticist Conflict and Classification

Phylogenetic systematic practice requires the conversion of a cladogram into a classification. Hennig (1966) realized that the cladistic system would raise conflicts with other types of classifications. First, branch points in the cladogram are delineators of successively inclusive (increasingly higher ranking) groups as we move toward the root. All subgroups of a group have the same character states that define the more inclusive group, unless recognized reversals have occurred. Any two sister...

Macroevolution and the Fall of Goldschmidt

Hopeful monsters and hopeless mooting. Studies of macroevolution tend to either idolize or denigrate the role of the geneticist Richard Goldschmidt. I find myself in between the extremes. He is best remembered for hopeful monsters (Goldschmidt 1933, 1940), those few monstrosities that he claimed to be the stuff of major species-level saltations in evolution. He relied on hypothetical chromosomal mutations that accumulated cryptically in populations until a threshold was breached, propelling the...

Preface to the First Edition

I have so many things to write about, that my head is as full of oddly assorted ideas, as a bottle on the table is filled with animals. - Charles Darwin, 1832, Rio de Janeiro Evolutionary biology enjoys the peculiar dual status of being that subject which clearly unites all biological endeavors, while occasionally seeming to be nearly as remote from complete understanding as when Darwin brought it within the realm of materialistic science. Somehow, the basic precepts first proposed by Darwin...

Advantages of the Genealogical Approach

Genealogies and character transitions. A framework established from a genealogical algorithm permits a useful analysis of character variation in the context of macro-evolutionary hypotheses. Many macroevolutionary hypotheses attempt to provide mechanisms to explain differential taxon longevity. Claims that taxon longevity depends on biogeographic range (e.g., Boucot 1978 Jackson 1974 Levinton 1974) or that taxon longevity is the result of differential speciation rate or survival of species...

Pelmatza Eleutherza

Permission For Caminalcules

CA HE CR CY ED A 0 EC HO CA HE CR CY ED A 0 EC HO Figure 2.17. A partial cladogram of the Echinodermata, including some fossil groups. HO Holothuroids EC Echinoids O Ophiuroids A Asteroids ED Edrioasteroids CY Cystoids CR Crinoids HE Helicoplacoids CA Carpoids. extinct after Smith 1984 . Figure 2.17. A partial cladogram of the Echinodermata, including some fossil groups. HO Holothuroids EC Echinoids O Ophiuroids A Asteroids ED Edrioasteroids CY Cystoids CR Crinoids HE Helicoplacoids CA...

Cladograms and phylogenies

A cladogram is a diagram posed as a hypothesis of the genealogical relationships among a series of taxa, grouped by their synapomorphies. A phylogeny, by contrast, is a hypothesis depicting the exact history of the evolutionary connections among the taxa. It may invoke a specific extinct ancestor that is not preserved as a fossil. I illustrate the distinction between a cladogram and a phy-logeny in Figure 2.5. For the two-taxon case, we assume that one or the other...

Fossil Caminalcules

In a phylogeny, phenetic groupings will fail to link the genealogically closest branch points and place emphasis on the degree of phenetic divergence. This criticism, which was Farris's fatal shot at phenetics, has come back to haunt phylogenetic approaches as well. Felsenstein 1982 pointed out that unequal rates of evolution, combined with short internal internode lengths, is an impediment to the success of phylogenetically based methods employing parsimony. This was shown in a simulation...