scholarly journals Evolutionary relationships between the varieties of green algae Pediastrum boryanum and P. duplex s.l. (Chlorophyceae, Hydrodictyaceae)

Fottea ◽  
2018 ◽  
Vol 18 (2) ◽  
pp. 170-188 ◽  
Author(s):  
Joanna Lenarczyk ◽  
Marta Saluga
Keyword(s):  
Green Algae ◽  
Evolutionary Relationships ◽  
Pediastrum Boryanum

scholarly journals Evolutionary relatedness does not predict competition and co-occurrence in natural or experimental communities of green algae

2015 ◽  
Vol 282 (1799) ◽  
pp. 20141745 ◽  
Author(s):  
Markos A. Alexandrou ◽  
Bradley J. Cardinale ◽  
John D. Hall ◽  
Charles F. Delwiche ◽  
Keith Fritschie ◽  
...  
Keyword(s):  
Green Algae ◽  
Species Interactions ◽  
Laboratory Experiments ◽  
Evolutionary Relationships ◽  
Biological Traits ◽  
Phylogenetic Distance ◽  
Ecological Data ◽  
Experimental Systems ◽  
Evolutionary Relatedness ◽  
Close Relatives

The competition-relatedness hypothesis (CRH) predicts that the strength of competition is the strongest among closely related species and decreases as species become less related. This hypothesis is based on the assumption that common ancestry causes close relatives to share biological traits that lead to greater ecological similarity. Although intuitively appealing, the extent to which phylogeny can predict competition and co-occurrence among species has only recently been rigorously tested, with mixed results. When studies have failed to support the CRH, critics have pointed out at least three limitations: (i) the use of data poor phylogenies that provide inaccurate estimates of species relatedness, (ii) the use of inappropriate statistical models that fail to detect relationships between relatedness and species interactions amidst nonlinearities and heteroskedastic variances, and (iii) overly simplified laboratory conditions that fail to allow eco-evolutionary relationships to emerge. Here, we address these limitations and find they do not explain why evolutionary relatedness fails to predict the strength of species interactions or probabilities of coexistence among freshwater green algae. First, we construct a new data-rich, transcriptome-based phylogeny of common freshwater green algae that are commonly cultured and used for laboratory experiments. Using this new phylogeny, we re-analyse ecological data from three previously published laboratory experiments. After accounting for the possibility of nonlinearities and heterogeneity of variances across levels of relatedness, we find no relationship between phylogenetic distance and ecological traits. In addition, we show that communities of North American green algae are randomly composed with respect to their evolutionary relationships in 99% of 1077 lakes spanning the continental United States. Together, these analyses result in one of the most comprehensive case studies of how evolutionary history influences species interactions and community assembly in both natural and experimental systems. Our results challenge the generality of the CRH and suggest it may be time to re-evaluate the validity and assumptions of this hypothesis.

The Evolutionary Relationships between Endosymbiotic Green Algae of Paramecium bursaria Syngens Originating from Different Geographical Locations

2016 ◽  
Vol 64 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Patrycja Zagata ◽  
Magdalena Greczek-Stachura ◽  
Sebastian Tarcz ◽  
Maria Rautian
Keyword(s):  
Green Algae ◽  
Paramecium Bursaria ◽  
Evolutionary Relationships ◽  
Geographical Locations

Freeze-Fracture Replication in the Ultrastructure of Blue-Green Algae

1967 ◽  
Vol 25 ◽  
pp. 74-75
Author(s):  
L. V. Leak
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Green Algae ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Electron Microscopic ◽  
Photosynthetic Membranes ◽  
Blue Green Algae ◽  
Cell Biol ◽  
Cellular Components

Electron microscopic observations of freeze-fracture replicas of Anabaena cells obtained by the procedures described by Bullivant and Ames (J. Cell Biol., 1966) indicate that the frozen cells are fractured in many different planes. This fracturing or cleaving along various planes allows one to gain a three dimensional relation of the cellular components as a result of such a manipulation. When replicas that are obtained by the freeze-fracture method are observed in the electron microscope, cross fractures of the cell wall and membranes that comprise the photosynthetic lamellae are apparent as demonstrated in Figures 1 & 2.A large portion of the Anabaena cell is composed of undulating layers of cytoplasm that are bounded by unit membranes that comprise the photosynthetic membranes. The adjoining layers of cytoplasm are closely apposed to each other to form the photosynthetic lamellae. Occassionally the adjacent layers of cytoplasm are separated by an interspace that may vary in widths of up to several 100 mu to form intralamellar vesicles.

A Scanning Electron Microscopic Study of Pro-Vascular Cellular Morphology in Chaetophora Incressata

1985 ◽  
Vol 43 ◽  
pp. 638-639
Author(s):  
A. E. Hotchkiss ◽  
A. T. Hotchkiss ◽  
R. P. Apkarian
Keyword(s):  
Green Algae ◽  
Vascular Plants ◽  
Vascular System ◽  
Higher Plants ◽  
Wall Structure ◽  
Electron Microscopic ◽  
Physiological Processes ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Multicellular green algae may be an ancestral form of the vascular plants. These algae exhibit cell wall structure, chlorophyll pigmentation, and physiological processes similar to those of higher plants. The presence of a vascular system which provides water, minerals, and nutrients to remote tissues in higher plants was believed unnecessary for the algae. Among the green algae, the Chaetophorales are complex highly branched forms that might require some means of nutrient transport. The Chaetophorales do possess apical meristematic groups of cells that have growth orientations suggestive of stem and root positions. Branches of Chaetophora incressata were examined by the scanning electron microscope (SEM) for ultrastructural evidence of pro-vascular transport.

Biochemical Composition of Green Algae at Different Stages of Their Growth

2015 ◽  
Vol 51 (4) ◽  
pp. 39-45
Author(s):  
N. I. Kirpenko ◽  
O. M. Usenko ◽  
T. O. Musiy
Keyword(s):  
Green Algae ◽  
Biochemical Composition
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