scholarly journals Study of the Biological Diversity of Benthic algae in the Tigris River, Baghdad - Iraq

2021 ◽  
Vol 779 (1) ◽  
pp. 012126
Author(s):  
Hind Ibrahem Ahmad
Keyword(s):  
Biological Diversity ◽  
Benthic Algae ◽  
Tigris River

scholarly journals Qualitative and Quantitative study of Epipelic algae in Tigris River within Baghdad City, Iraq

2014 ◽  
Vol 11 (3) ◽  
pp. 1074-1082
Author(s):  
Baghdad Science Journal
Keyword(s):  
Benthic Algae ◽  
Lotic Ecosystems ◽  
Qualitative And Quantitative ◽  
Tigris River ◽  
Spatial And Temporal Distributions ◽  
Number Species ◽  
Study Sites ◽  
One Year ◽  
Qualitative And Quantitative Study

The present study conducted to study epipelic algae in the Tigris River within Baghdad city for one year from September 2011 to August 2012 due to the importance role of benthic algae in lotic ecosystems. Five sites have been chosen along the river. A total of 154 species of epipelic algae was recorded belongs to 45 genera, where Bacillariophyceae (Diatoms) was the dominant groups followed by Cyanophyceae and Chlorophyceae. The numbers of common types in three sites were 47 species. Bacillariophyceae accounted 88.31% of the total number of epipelic algae, followed by Cyanophyceae 7.14 % and Chlorophyceae 4.55%. A 85 species (29 genera) recorded in site 1, 103 species (34 genera) in site2, 112 species (35 genera) in site3, 96 species (32 genera) in site4, and 85 species (29 genera) in site5. Spatial and temporal distributions of epipelic algae were noticed in this study. The higher total number of epipelic algae (91504.01cell cm-2) was recorded at site 5 in spring 2012, while the lower was (37017.98cell cm-2) in summer 2012 at site1. Some genera have recorded higher number species during the study period; these genera were Nitzschia, Navicula, Cymbella, Gomphonema, Synedra, Achnanthes, Oscillatoria, and Lyngbya. The study revealed that Bacillariophyceae were more prominent within all study sites and followed by Cyanophyceae, while a few numbers of Chlorophyceae was appeared.

scholarly journals Benthic Algae in Lower Zab Tributary and Tigris river

2004 ◽  
Vol 1 (2) ◽  
pp. 311-316
Author(s):  
Baghdad Science Journal
Keyword(s):  
Benthic Algae ◽  
Nitzschia Palea ◽  
Tigris River ◽  
Pennate Diatoms ◽  
Achnanthes Minutissima

Benthic algae of Tigris river and one of its northern tributary the lower Zab were study at monthly intervals during Nov. 2001-Oct. 2002. Four sites were selected, a total of 115 species of algae were identified during this study, diatoms was the dominating group (86 species) followed by Chlorophyta (18 species), Cyanophyta (7species), Euglenophyta (2 species) and one species for each of Pyrrophyta and Chryzophyta. Pennate diatoms formed the major density within the identified algae and distributed among all stations especially the species Achnanthes minutissima, Navicula gracilis and Nitzschia palea, the diatoms bloomed in spring and autumn seasons. Bio-diversity and density of benthic algae in Tigris river was affected negatively by the entering waters from Lower Zab tributary, this was indicated by the decreasing values after the confluence.

Letters. Biological diversity

1983 ◽  
Vol 17 (4) ◽  
pp. 160-160
Author(s):  
David Whitman
Keyword(s):  
Biological Diversity

Homology, Genes, and Evolutionary Innovation

2014 ◽  
Author(s):  
Günter P. Wagner
Keyword(s):  
Evolutionary Biology ◽  
Regulatory Networks ◽  
Biological Diversity ◽  
Cell Types ◽  
Origin And Evolution ◽  
Major Transitions ◽  
Form And Function ◽  
Historical Continuity ◽  
Evolutionary Innovation ◽  
Character Identity

Homology—a similar trait shared by different species and derived from common ancestry, such as a seal's fin and a bird's wing—is one of the most fundamental yet challenging concepts in evolutionary biology. This book provides the first mechanistically based theory of what homology is and how it arises in evolution. The book argues that homology, or character identity, can be explained through the historical continuity of character identity networks—that is, the gene regulatory networks that enable differential gene expression. It shows how character identity is independent of the form and function of the character itself because the same network can activate different effector genes and thus control the development of different shapes, sizes, and qualities of the character. Demonstrating how this theoretical model can provide a foundation for understanding the evolutionary origin of novel characters, the book applies it to the origin and evolution of specific systems, such as cell types; skin, hair, and feathers; limbs and digits; and flowers. The first major synthesis of homology to be published in decades, this book reveals how a mechanistically based theory can serve as a unifying concept for any branch of science concerned with the structure and development of organisms, and how it can help explain major transitions in evolution and broad patterns of biological diversity.

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