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91.
Li Gang 《植物分类学报:英文版》1993,31(1):80-99
The theoretical bases and approaches of cladistics and some specific
problems that, directly or indirectly, rely on cladistic analysis for their revolution, are outlined and discussed. Seven sections comprise this paper: a ) the philosophical foundation of cladistics; b) the theoretical tenets of cladistics; c) the
operational procedure of cladisties; d) three schools of classification; e) cladistics
and biogeography; f) cladistics and hybrid recognition; and g) is cladistic systematics a scientific theory ?
Considerations of scientific methodology involve philosophical questions.
From this point, Popper'falsificationism serves a good foundation. Popper
emphasizes that all scientific knowledge is hypothetical-deductive, consisting of
general statements (theories) that can never be confirmed or verified but only
falsified. The theories, that can be tested most effectively, are preferable.
Cladistics, aiming at generating accurately expressed and strictly testable systematic
hypotheses, is well compatible with this requirement.
The principles central to the cladistic theory and methodology are: the
Principle of Synapomorphy; the Principle of Strict Monophyly; and the Principle
of Strict Parsimony. The first requires forming nested groups by nesting
statements about shared evolutionary novelties (synapomorphy) postulated from
observed similarities and is the primary one. The second is mainly
methodological, subject to modification and compromise. The principle of strict
parsimony specifies the most preferable hypothesis (namely the one exhibiting
the most congruence in the synapomorphy pattern).
The operational procedure that might be followed in formulating and testing
hypotheses of the synapomorphy pattern (the cladogram itself) consists of five
steps. The erections of monophyletic groups, to a greater or lesser extent, rely
on the hypothesis of the previous systematic studies and is the starting point for
cladistic analysis. Character analysis, which focuses on character distribution and
determination of the polarities, decides the reconstructed phylogeny. A detailed discussion on the methodological principles for identifying transformation sequence is
presented. Many algorithms have been designated to infer the cladogram,
and are basically of parsimony techniques and Compatibility techiques. The thus
yielded cladograms, with their expected pattern of congruent synapomorphies, are
tests of a particular hypothesis of synapomorphy and reciprocally synapomorphies
are tests of cladistic hypothesis (cladogram). Such reciprocity is a strong stimulus
to profound understanding on phylogenetic process and phyletic relationships. The
cladogram and the Linnaean classification have the identical logic structure and
the set-membership of the two can be made isomorphic.
There are three principal approaches to biological classification : cladistics,
phenetics and evolutionary classification. Cladistics is the determination of the
branching pattern of evolution, and in the context of classification, the development of nested sets based on cladograms. Phenetics is the classification by overall
similarities, without regard to evolutionary considerations. Evolutionary classification attempts to consider all meaningful aspects of phylogeny and to use these for
making a classification. The last approach has been done intuitively, without explicit methods. An enumeration of their differences and a discussion on their relative merits are presented.
Three theoretical approaches have been proposed for interpreting
biogeographical history: the phylogenetic theory of biogeography, classical evolutionary biogeography and vicariance biogeography. The former two show some
similarities in that they usually look upon biogeography in terms of centers of
origin and dispersal from the centers. But the first puts a strong emphasis on the
construction of hypotheses about the phylogenetic relationships of the organisms in
question and the subsequent inference of their geographic relationships; the second
advocates a theory which does not have a precise deductive link with phylogenetic
construction and often results in wildly narratative-type hypotheses. The vicariance
approach de-emphasizes the concepts of centers of origin and dispersal and attempts to analyse distribution patterns in terms of subdivision (vicariance) of
ancestral biotas. The development of the theory of plate tectonics and its
universal acceptance enormously stimulate biogeographers to look at the world's
continents and oceans from a mobilist point, which, along with the establishment
of the rigorous tool of the phylogenetic analysis (cladistics), profoundly reshapes
the above three theories.
Hybridization and polyploidy are outstanding features of many plant groups.
But hybridization, or reticulate evolution, is inconsistent with the basic concepts
of cladistics which is an ever-branching pattern. Cladists have suggested several
approaches. One of them analyses all the taxa by a standard cladistic procedure
and closely examines the cladograms for polytomies and character conflicts that
may indicate possible hybrids. Such generated hypothesis of hybridization can be
corroborated or falsified by other forms of data, such as distribution, polyploidy,
karyotype and pollen fertility.
There are three criteria to justify a theory to be scientific: a) whether it is a
theory composed of hypotheses strictly falsifiable; b) whether it has predictive
effect; and c) whether it has a explanatory value. Cladistic systematics aims at
generating cladograms, which are hypotheses of the nested pattern of
synapomorphy, phylogenetic process and phyletic relationships, susceptible to
testing by postulated synapomorphies. The predictive effect of systematics relies on
the acceptance of hypotheses of congruence about the correlation of characters,
which has been well founded. For non-systematic biologists, phylogenetic
classification can be used as axiom to form a preliminary and fundamental
explanation. 相似文献
92.
《Arthropod Structure & Development》2014,43(1):63-75
The external and internal anatomy of millipedes (Diplopoda) is poorly known compared to some of the other myriapod and arthropod groups. Due to both language barriers, which hindered the assessment of the character-rich older literature, and non-phylogenetic thinking, our knowledge of morphological characters useful for phylogenetic work diminished over the last decades. Here, a new character matrix with 64 characters, mainly derived from old literature data, is used to reconstruct a phylogeny of Diplopoda. As a tool to further our knowledge about the morphology of the different millipede orders, we show how micro-computer tomography (μCT) can be used to assess and illustrate specific parts of the Platydesmida. With the advent of μCT it is now possible to analyse many taxa and characters in a comparatively short time. A focus is put on potential phylogenetically useful characters. Our results support a Verhoeffian classification of the Diplopoda: Polyxenida + Chilognatha. Pentazonia are the sistergroup to the Helminthomorpha. Colobognatha form the sistergroup to Eugnatha, the latter split into monophyletic Juliformia and Polydesmida + Nematophora. 相似文献
93.
Louise S. Mead 《Evolution》2009,2(2):310-314
A common misconception of evolutionary biology is that it involves a search for “missing links” in the history of life. Relying
on this misconception, antievolutionists present the supposed absence of transitional forms from the fossil record as evidence
against evolution. Students of biology need to understand that evolution is a branching process, paleontologists do not expect
to find “missing links,” and evolutionary research uses independent lines of evidence to test hypotheses and make conclusions
about the history of life. Teachers can facilitate such learning by incorporating cladistics and tree-thinking into the curriculum
and using evograms to focus on important evolutionary transitions. 相似文献
94.
A simple example of conflicting data, relevant to comparison between standard and three‐item parsimony analysis, is two characters (nodes, trees) differently relating four taxa: (AB)CD and A(BCD). This conflict is differently resolved by standard and three‐item analysis, which with fractional weighting yields the unique result (AB)(CD). There is reason to consider this result as the more accurate resolution of these conflicting data. 相似文献
95.
Tomohisa Yukawa Hideaki Ohba Kenneth M. Cameron Mark W. Chase 《Journal of plant research》1996,109(2):169-176
Phylogenetic analyses using two chloroplast DNA data sets, derived from variation of the ribulose-bisphosphate carboxylase
gene (rbcL) and restriction sites, were performed to examine relationships among 13 taxa in subtribe Dendrobiinae, one of the most
taxonomically complicated groups in Orchidaceae, and its putative sister groups. Owing to a limited number of informative
substitutions, therbcL data set did not provide conclusive evidence in itself. The data set combiningrbcL and restriction site mutations, however, provided the following insights: (1)Pseuderia belongs with tribe Podochileae rather than tribe Dendrobieae. (2) Subtribe Dendrobiinae is monophyletic ifPseuderia is excluded. (3) ExcludingPseuderia, Dendrobiinae comprises three major clades: Clade 1 (Dendrobium sectionSpatulata, Cadetia, Diplocaulobium, andFlickingeria); Clade 2 (Dendrobium sectionsDendrobium andCallista); and Clade 3 (Epigeneium). (4)Epigeneium diverged early from the lineage including Clades 1 and 2. (5) Relative toCadetia, Diplocaulobium, andFlickingeria, Dendrobium is shown to be para-/polyphyletic. (6)Diplocaulobium andFlickingeria constitute a monophyletic clade, from which cladeDendrobium sectionSpatulata andCadetia form succesive sister groups. Among these results, (1) and (5) are especially stable in view of the congruence between the
separate and combined analyses as well as robust internal support. 相似文献
96.
Summary The secondary structure of 5S rRNA has been elucidated by a cladistic analysis resulting in minimal models for eukaryotes, eubacteria, and halophilic-methanogenic archaebacteria, as well as for an ur-5S rRNA. This ancestor of all present-day 5S rRNA molecules is compared with an ur-tRNA and can be fitted into a tRNA-like structure allowing tertiary-structure interactions at the equivalent positions. A phylogenetic analysis of eukaryotic 5SrRNA and 16S rRNA sequences confirms particular monophyletic taxa: rhodophytes (red algae), chlorobionts (green algae and plants), metazoans (multicellular animals), euglenozoans (euglenids and trypanosomatids), a group of zygomycetes (excluding Kickxellales), a group of ascomycetes (excluding Protomycetales), two distinct groups of basidiomycetes, and a group consisting of phaeophyceans (brown algae) and oomycetes (water molds). The Euglenozoa show a distinct relation to the Eumycota (true fungi) and Metazoa. An analysis of archaebacterial sequences substantiates the paraphyletic nature of this third urkingdom defining the eubacteria as a sister group of the halophile-methanogens and defining the eukaryotes as a sister group of a particular lineage of the eocytes/sulfur-dependents. The latter fact implies that even the eocytes/sulfur-dependent archaebacteria are paraphyletic.Presented at the FEBS Symposium on Genome Organization and Evolution, held in Crete, Greece, September 1–5, 1986Dedicated to the memory of Erik Huysmans who died on July 8, 1986, at the age of 29. 相似文献
97.
Thomas G. Lammers Tod F. Stuessy Mario O. Silva 《Plant Systematics and Evolution》1986,152(3-4):243-266
The systematic relationships ofLactoridaceae are problematical, with alternative assignments toMagnoliales, Laurales, andPiperales. Phenetic analyses suggest thatLactoridaceae are best accomodated withinMagnoliales and are most closely related toAnnonaceae. Cladistic analyses indicate that the family is a relatively derived member of theMagnoliales, with affinities toAnnonaceae, Eupomatiaceae, Himantandraceae, andMyristicaceae. These analyses together with fossil pollen data are used to interpret the phylogeny ofLactoridaceae and its relatives. 相似文献
98.
B Blumenberg 《Bio Systems》1985,18(2):149-184
Sexual dimorphism as a function of variation in hominoid tooth metrics has been investigated for four groups of taxa: Recent great apes (two subfamilies), Dryopiths (one subfamily), Ramapiths (one subfamily) and hominids (one family). Gorilla, and to a lesser extent Pan, appear characterized by very high levels of sexual dimorphism and meet several criteria for statistical outliers. Recent great apes are the only group exhibiting consistently high levels of sexual dimorphism. Ramapiths are the only group characterized by low levels of sexual dimorphism and their relative canine length is most similar to Dryopiths. Both Dryopiths and hominids contain taxa with low and intermediate levels of sexual dimorphism. The Gingerich and Shoeninger hypothesis relating coefficients of variation to occlusal complexity is supported. Non-parametric statistics suggest that homogeneity of coefficient of variation profiles over most of the tooth row is characteristic of only the Dryopiths and a composite data set composed of the Dryopith plus Ramapith tooth measurements. Oxnard's model for the multifactorial basis of multiple sexual dimorphisms is also supported. The Dryopith and hominid patterns of sexual dimorphism are similar, an observation that suggests phylogenetic relationship. At the taxonomic level of subfamily or family, sexual dimorphism is a character of cladistic usefulness and possible phylogenetic valence. Assuming that breeding system and sexual dimorphism are functional correlates as many workers suggest, then Ramapithecus sp. China, Sivapithecus indicus and possibly Australopithecus boisei are good candidates for having possessed monogamous breeding/social structures. All Dryopith taxa, S. sivalensis, Sivapithecus sp. China, A. afarensis, Homo habilis and H. erectus emerge as the best candidates for having possessed a polygynous breeding/social structure. No biometrical affinities of Ramapiths with hominids can be demonstrated and some phylogenetic relationship with Dryopiths is suggested. Kay's interpretation of Ramapith sexual dimorphism and taxonomic affinity is not supported. The lack of control over temporal and geographic range variation is discussed and the loose association of these variables with differences in tooth morphology is noted. The high heritability of tooth size also suggests that assignment of "high" or "low" index values to extinct taxa as a measure that describes evolving clades at discrete points in evolutionary time is appropriate.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
99.
We previously isolated and characterized a new free amino acid withd-configuration at the α-carbon,trans-3, 4-dehydro-d-2-aminopimelic acid and its related amino acids,d-2-aminopimelic acid and 4-hydroxy-l-2-aminopimelic acid fromAsplenium unilaterale. In this paper, we report that the biosynthetic relationshps among these three amino acids were studied using14C-and3H-labeled compounds as tracers. Glutamate and aspartate were shown to be good precursors and it was suggested that 4-hydroxy-l-2-aminopimelic acid is biosynthesized first and the twod-amino acids are derived from it. Furthermore, the distribution patterns of these non-protein amino acids inAsplenium sect.Hymenasplenium were examined in detail and they were evaluated by their biosynthetic pathway. Morphological characters especially on their
rhizomes were also examined and their character phylogeny was determined by outgroup comparison. Taking all the characters
available into account, the phylogenetic relationship among 7 species ofAsplenium sect.Hymenasplenium in Japan and Taiwan is discussed by the transformed cladistic method. 相似文献
100.
Much cladistic theory is flawed because it confuses two temporal sequences: 1. cladogenetic (branching) chronology; 2. anagenetic (primitive-advanced) polarity. The first is largely inherent and exposed by a straigram; the second requires an independent polarisation of the changes subsequent to cladogenetic branchings. Failure to consistently distinguish between these always causes confusion, but destroys cladistic theory, because plesiomorphy and apomorphy refer to anagenesis, and autapomorphy and synapomorphy refer to cladogenetis. They cannot, however, be identified wholly independently, because cladogenetic chronology establishes anagenetic polarity by out-grouping, under limited conditions; and anagenetic polarity establishes cladogenetic chronology in multiple cladistic events. The principle ‘common characters are primitive’ is more accurately expressed as ‘characters of greater s read are cladogenetically earlier', and establishes cladogenetic relationships, never anagenetic polarity as usually thought. The full temporal analysis of biological patterns, therefore, involves eight stages: 1. Homologue identification; 2. Homolostrata delimitation and definition; 3. Stratigram formation; 4. Cladogenetic sequencing; 5. Anagenetic polarity determination (chronogramy); 6. Cladogenetic and anagenetic co-analysis; 7. Cladogram construction; 8. Phylogenetic interpretation. 相似文献