摘要:

SummaryThe phylogeny of eucaryotic algae can be best illustrated by establishing lines of algal evolution leading from simple unicells to an elaborated tissue thallus. These evolutionary lines of algal morphological progress represent the Classes. The single grades of algal advance in a class represent a lower taxonomic rank, the Order, which is thus defined morphologically by the level of plant body construction. It represents a particular degree of morphological differentiation and a step in the phylogenetic progress. One or more parallel evolutionary lines may occur within the highest rank of taxa, the Division. Apart from the procaryotic Cyanophyceae, nine classes evolved in parallel within the plants called algae: 1. Chlorophyceae (the ancestors of higher land plants), 2. Conjugatophyceae, 3. Charophyceae, 4. Chrysophyceae, 5. Xanthophyceae, 6. Bacillariophyceae, 7. Phaeophyceae, 8. Dinophyceae, 9. Rhodophyceae. Flagellates that cannot be placed with respect to their morphology and structure in monadoid orders of algal classes, are excluded from the system and termed “residual flagellates”: Euglenales, Cryptomonadales, Vacuolariales, Dictyochales and other orders of colorless flagellates.

ISSN:0040-0262    

DOI:10.2307/1218767

出版商:Wiley    

年代:2019

数据来源: WILEY

ISSN:0040-0262    

DOI:10.1002/j.1996-8175.1974.tb04038.x

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryThe affinities of the phylum Charophyta and the general evolutionary trends undergone by this group since the Late Silurian are discussed briefly. The main emphasis is placed on the Mesozoic family Clavatoraceae as the rapid changes in the utricle, a supplementary envelope investing the female gametangium, have led to quite diversified and elaborate structures that allow more detailed phylogenetic studies.Three lineages are analysed which, throughout the Lower Cretaceous, show a sequence of gradual changes linking quite distinct extreme types. These lineages concern respectively the genusGlobator, the generaPerimnesteandAtopochara, and the generaFlabellocharaandClypeator, for each of which new data are presented.The relationships between the three subfamilies and the several genera of the Clavatoraceae are discussed, as well as the mode of extinction of the group at the end of the Cretaceous and the rates of taxonomic evolution in the studied lineages. A biochronological zonation is established for the Lower Cretaceous on the basis of the three described evolutionary sequences. The zonation, with nine biozones from the Berriasian to the Cenomanian, seems to be useful in correlating non‐marine formations on a worldwide scale.

ISSN:0040-0262    

DOI:10.2307/1218769

出版商:Wiley    

年代:2019

数据来源: WILEY

ISSN:0040-0262    

DOI:10.1002/j.1996-8175.1974.tb04040.x

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummarySarcodinid taxonomy was previously revised by Jahn and Bovee (1965) on the basis of the two readily distinguishable methods of ameboid locomotion, respectively the contractile‐hydraulic and the active sliding systems. Pseudopodial form and structure were regarded as characters of ordinal rank. The present general summary of the classification and the status of further investigations, continues the reclassification to the family level, citing authors and dates, as well as presenting brief definitions of subclasses, orders (and superorders and suborders where applicable), families and subfamilies. New taxa proposed include the families Striamoebidae and Discamoebidae, both of Bovee and Jahn, and their type genera,StriamoebaandDiscamoebaof Bovee, andPentagoninaBovee and Jahn (nom. nov. proPentagoniaGauthier‐Lièvre and Thomas, 1958nonCozzens, 1846). The tentative phylogenetic scheme proposed by Bovee and Jahn in agreement with the symbiotic theory of eukaryotic origins is briefly outlined.

ISSN:0040-0262    

DOI:10.2307/1218771

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryStudies on the evolution and phylogeny of various groups of the Protozoa, a major taxon or portion of the eukaryotic kingdom Protista, have been proceeding apace, particularly in recent years, although they appear to have attracted little attention to date among students of evolutionary biology in general. In searching for the reasons for this apparent fact the “shortcomings” of the protozoa themselves, as objects of phylogenetic investigation, may be held responsible. Such difficulties are discussed under six broad headings: the very nature of the Protozoa (microscopic size, unicellularity, common absence of sexuality, ubiquity), the frequent lack of fossil material, the paucity of described species, the scarcity of morphological features, the even greater rareness of non‐morphological characteristics usable in comparative study, and the unevenness in both our specific and general knowledge of these microorganisms. At the same time, new approaches and recent research in progress mitigate the awesomeness of these challenges to a degree which should allow us to recognize that such work is not being carried out entirely in vain. Many examples, often from the ciliate literature, are cited in illustration of points made. If protozoologists interested in phylogenetic problems can more successfully avoid the pitfalls inherent in their research, apply approaches broader in nature yet technically as sophisticated as possible, take into account constructive criticism, whether from insiders or outsiders, and learn from the experiences of other evolutionary biologists, they and their works will then be predictably deserving of considerably wider respect and recognition than apparently they are presently accorded.

ISSN:0040-0262    

DOI:10.2307/1218772

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryVariation was measured in samples of populations of species from four plant families including tropical, temperate and cosmopolitan taxa. Populations of species of Asclepiadaceae, Bromeliaceae, Leguminosae and Umbelliferae were sampled. Employing a simple application of numerical phenetics and tested character lists, estimates of within‐group overall variation were made. The coefficients of phenetic variation (CPV) are compared among the various groups. The groups considered are populations as well as taxa at several levels in the classification hierarchy, although in all cases, individuals sampled randomly from putative populations are the operational taxonomic units (OTUs). A small number of individuals is employed with a large number of characters. This application of numerical phenetics serves both alpha taxonomic and biosystematic goals and an OTU x OTU matrix of distance values is the basis for obtaining estimates of a population's variability. The phenetic distances between OTUs are the variates. Distinct trends of within‐group variation are consistent as they were revealed in the four families. Intrapopulational coefficient of phenetic variation for populations of the tropical family Bromeliaceae is estimated as nearly double that for the other three families. The intraspecific variation as portrayed by CPV in the Asclepiadaceae and Leguminosae is about half that for the tropical family, Bromeliaceae. As sampled a clear distinction is evidenced in the change in variation between various taxonomic ranks for the families. The difference in CPV between the intrapopulational and intraspecific levels for the Leguminosae and Bromeliaceae is nearly double the difference between these two ranks for the Asclepiadaceae. Results show that the method has descriptive and heuristic value for systematics.

ISSN:0040-0262    

DOI:10.2307/1218773

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryThe discovery of betalains and specific P‐type sieve‐tube plastids inHalophytum, a genus which has been treated as both a member of Chenopodiaceae as well as a distinct family, confirms the alignment of the genus with the nine betalain‐containing families of the Centrospermae all of which have characteristic P‐type sieve‐tube plastids.

ISSN:0040-0262    

DOI:10.2307/1218774

出版商:Wiley    

年代:2019

数据来源: WILEY

ISSN:0040-0262    

DOI:10.1002/j.1996-8175.1974.tb04045.x

出版商:Wiley    

年代:2019

数据来源: WILEY

摘要:

SummaryThe discovery of betalains and P‐type sieve‐tube plastids inPetiveriaandAgdestis(Phytolaccaceae) supports the assignment of these genera to the Centrospermae.

ISSN:0040-0262    

DOI:10.2307/1218776

出版商:Wiley    

年代:2019

数据来源: WILEY