A New Method for Cladistic Analysis—Median Elimination Series (MES)-文献传递-植物通论文库

作者：Li Chao-Luan

期刊：植物分类学报 1990年 1期

Keywords:Cissus, Cladistic analysis, Co-variation, Median Elimination Series, Reverse evolution,

Abstract:

The use of parsimony (or the principle of simplicity) in phylogenetic infere-

nce is reviewed. The major problem in using parsimony for phylogenetic reconstruction is

that neither a single solution for a given set of data nor the most parsimonious tree could be

provided. Therefore, based on recognition and judgement of similarity of organisms by Hen-

nig‘s advanced character (1965) and some particular principles from evolutionary theory of

Darwinism accepted by many systematists as general truths (Bonde 1977; Wiley 1975; Gaffrey

1979), the author has developed a new method, Elimination Series through Median Selection

(Median Elimination Series, MES for short), for phylogenetic analysis. In addition to using

the advanced characters for understanding the relationships between taxa, MES emphasizes that

the mosaic characters including both primitive and advanced in an array of characters play

an important part in determining the nodes or branches and distinguishing the taxa.The

author considers median units as ancestors in a phylogenetic tree like Farris, but the concept

and algorithm of “median” differ from Farris‘ (1970) in: (1) The author‘s median involves

the top taxon and unplaced one, but Farris‘ median does the top taxon, its ancestor as well as

unplaced one; (2) The median taken by the author is of common value or the least one

among the associated characters of two taxa. However, the median taken by Farris is median

numerical value among the three (3) The median or median unit called by the author is the

numerical value of the relatively primitive character or taxon between the advanced characters

or the taxa stood apart from the original position. Farris‘ one is the median position or num-

ber in the center of three taxa or its associated characters. The author recognizes that rever-

sion of characters is possible and obtains the knowledge of it from observation and analysis

of characters of organisms or scientific experiment and distinguished through analysis of mor-

phocline and co-variation in a series of taxa, but not from induction only by mathematical

model based on the principle of simplicity. The author divides co-variation into 4 types:

1. Progressive co-variation. Transformation series of characters A and a is as follows:

A → A‘

a → a‘

reversed co-variation. Transformation series of characters A and a is as follows:

A ← A‘

a ← a‘

3. Progression-reversion co-variation. Transformation series of characters A and a is

follows:

A → A‘

a ← a‘

4. Reversion-progression co-variation. Transformation series of characters A and a is as

follows:

A ← A‘

a → a‘

The characters next to the arrows should be advanced. Co-variation for most of the species

of Cissus from China belongs to the type 1 and that for C. repanda Vahl. to the type 3, without

types 2 and 4. In determining the progressive co-variation, reverse evolution of character

could be distinguished through the analysis of morphocline and co-variation. The author has

recognized two types of cyclic polarity, including unidirectional and bidirectional ones. For

the former, the character may return back to the original state through more than one step. In

fact, this is a complex reversion. For the latter, the character may reach a advanced state from

the original one via two different ways. In fact, this is special progressive transformation se-

ries and it may often occur in complex reticulate evolution as a small net, for example, in evo-

lution of leaf fragment and others of angiosperms (Meyen 1973). The cyclic polarity in C.

repanda Vahl. is bidirectional (see transformation series 11 of the characters in Cissus). Trans-

formation series of All the characters have been determined on the basis of analysis of mor-

phocline, co-variation and cyclic polarity. In this paper, the three steps of understanding

phylogenetic system are developed: (1) recognition of homologous characters; (2) discovery of

internal relationships between homologous characters in order to obtain transformation series

or phylogeny of homologous characters; (3) discovery of internal relationships between phylo-

genies of homologous characters in order to get a phylogenetic system of organisms or approa-

ching understanding essence of evolution. The result inferred by MES is based on some prin-

ciples of evolution from Darwin and Hennig but not judged by the principle of simplicity or

parsimony from Popper (1960, 1968). The statement in this paper attempts to show that if a

dilemma in modern cladistics could be solved, its principles must be reconsidered.

A New Method for Cladistic Analysis—Median Elimination Series (MES)

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