ISSN:0373-4137    

DOI:10.1080/11250008909355643

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0373-4137    

DOI:10.1080/11250008909355644

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In order to construct a broad molecular phylogeny of protists, we have sequenced the 5’ terminal part of the nuclear encoded large subunit ribosomal RNA from representatives of several pro‐tistan phyla. Using a distance matrix‐method we have constructed a dendrogram which reveals, in agreement with classical systematics, a number of clusters separated by large evolutionary distances (those of the ciliates, the chromophytes, the chlorophytes, ...). The divergence of these groups is far antedated by the emergence of some flagellated groups such as the Euglenozoa. From this analysis, several major biological inferences can be made among which the ancient origin of the flagellar apparatus and the late occurrence of chloroplastic endosymbiosis.

ISSN:0373-4137    

DOI:10.1080/11250008909355645

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Some background information is first presented concerning the historically and evolutionarily significant prokaryote‐eukaryote split of the biotic world, widely accepted some 25 years ago, and the (re)emergence of the field of neoHaeckelian protistology in still more recent times. Two questions are then posed: how did eukar‐yogenesis come about, and what protistan groups may have served as progenitors of the plant, fungal, and animal kingdoms? Before either of these complex inquiries can be discussed properly, some data need to be given concerning the protists themselves, and progress made to date in research on these evolutionarily important forms of life requires brief review.

ISSN:0373-4137    

DOI:10.1080/11250008909355646

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0373-4137    

DOI:10.1080/11250008909355647

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The locomotory patterns of Protozoa have been compared, in an attempt to draw a general picture of how these protists solved the problem of relating properly with their environment. Locomotion seems to have evolved according to a progressive complexification not only of the engines (from prokaryotes to eukaryotes) but also of the systems that control how they work (different beating patterns of the eukaryotic flagella and cilia under a sophisticated control of the electrophysiological potentials of the cell). Among ci‐liates, the Hypotrichida with their ciliary engines (cirri) and electric control (cell membrane more complex and sophisticated), have reached the highest peak of specialization. The evolutionary leap to a multicellular organization typical of Metazoa did not play any relevant role in locomotion: it was only with the appearance of the most complex phyla (Mollusca, Annelida) that a new locomotory asset was gained (muscular layers or bundles) and perfected by the coupling of muscles and levers (art), especially by Arthropoda and Chordata.

ISSN:0373-4137    

DOI:10.1080/11250008909355648

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The homologies and analogies of the biological systems involved in the effects of heavy metals are examined in a phylogenetic perspective.

ISSN:0373-4137    

DOI:10.1080/11250008909355649

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0373-4137    

DOI:10.1080/11250008909355642

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor