Evolution And Speciation In Protozoa
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Evolution And Speciation In Protozoa
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Author : T.J. Pandian
language : en
Publisher: CRC Press
Release Date : 2023-02-24
Evolution And Speciation In Protozoa written by T.J. Pandian and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-02-24 with Science categories.
The polyphyletic Protozoa have explored the possibility of performing almost all metazoan functions with a few subcellular organelles. Their unicellularity and structural simplicity have (i) limited diversity to 32,950 species, (ii) restricted spatial distribution to aquatic habitats (94%, against 15% in Metazoa), (iii) demonstrated the ubiquitous dominance of clonality, (iv) reduced sexualization in 50% species, (v) facilitated the use of vegetative gametes in 40% species and (vi) secondary loss of sex in 10% species. With the fastest multiplication rates, i.e. once every 6-60 hours, they occur in high densities of 105-106 cell/ml. Their diverse and complicated life cycles are described in 30 types. Being risky, the cycle involves two hosts in clonality > hermaphroditism > motility. Motility ranges from 2-3 μm for Rhizopoda to 400-2,000 μm for Ciliophora. Not surprisingly, 6,800 species of arcellinids, filosians and formainifers are testated or shelled. Within 1,229 sessile species, the peritrichid and suctorian ciliates are better adapted to coloniality. Unlike those of many Metazoa, the protozoan cyst is a dynamic stage, in which clonal or sexual reproduction occurs. Over 81% protozoans encyst, as it ensures (i) 90% survival during unfavorable conditions (against 15 in 12% non-encysted protozoans), (ii) genome transfer through generations, (iii) dispersal into new habitats and (iv) transmission to new hosts. Their mean body size ranges from 2 μm to 2 mm – a range over 1,000-times – only 8% aquatic metazoans cover a similar size range. In comparison to 77% macrophagy in Metazoa, only 46% protozoans are macrophagous predators. Within motile microphagy, protozoans filter 3-2 times smaller food particle at 50% cheaper clearance cost. This efficiency has expanded microphagy to 15% in protozoans, against 3% in Metazoa. Hence, their turnover rate in trophic dynamics is twice faster than that of metazoans. Foraminifers serve as ecological sensitive indicators in petroleum exploration and rise in sea level. For the first time, incidences of clonality and meiosis as well as symbiosis and parasitism have been shown to hint at the origin and evolution of different protozoan taxonomic groups during the geological past.
Evolutionary Relationships Among Protozoa
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Author : Graham H. Coombs
language : en
Publisher: Springer
Release Date : 1998-10-31
Evolutionary Relationships Among Protozoa written by Graham H. Coombs and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998-10-31 with Science categories.
The evolutionary biology of protozoa is a field in which exciting changes are taking place. Relationships between different groups of protozoa are undergoing extensive review and the revised views will have significant repercussions for future investigations. New data from molecular and ultrastructural studies have changed our perception of evolution among this diverse group of organisms in recent years. This volume, part of the Systematics Association Special Volume Series, aims to review this important area and give an up-to-date synthesis of current understanding. The various chapters are deliberately broad in scope and explore areas such as the contribution of different techniques and approaches to the understanding of protistan evolution and the biochemical and physiological aspects of that evolution; there are also chapters that analyse and explore specific protistan groups. In addition some of the chapters discuss topics that are currently very controversial within this field, such as the finding that the 18S rRNA phylogenetic tree of protozoa is probably unreliable. The world-renowned editors have assembled an international team of outstanding scientists whose contributions have produced a volume of interest to all evolutionary biologists and especially those interested in protozoa.
Evolution And Speciation In Fungi And Eukaryotic Biodiversity
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Author : T. J. Pandian
language : en
Publisher: CRC Press
Release Date : 2023-10-13
Evolution And Speciation In Fungi And Eukaryotic Biodiversity written by T. J. Pandian and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-10-13 with Science categories.
Being sessiles like autotrophic plants and heterotrophics as animals, fungi are fascinating eukaryotes. In them, the need for external digestion has demanded surface expansion and limited tissues to 2/y. The mycorrhizas facilitate 85% angiosperms to acquire water and minerals, enhance productivity and fight against drought and pollutants. During the geological past, lichens have weathered rock and formed the present landscape. Only 121 fungal species excrete digestive enzymes to meet industrial demand. The beneficial fungi contribute 1,000 billion US$. Parasitic fungi cause 1.6 million human deaths and > 20% loss of commercial crops. Despite their ecological and economic importance, no university offers a degree course in Mycology. For 2,056,907 eukaryotic species, this book elaborates the role played by environmental factors (i) spatial distribution, (ii) light-temperature, (iii) precipitation-liquid water and biological attributes, (iv) cellularity, (v) symmetry, (vi) clonality, (vii) sexuality, (viii) modality and (ix) motility that either accelerate or decelerate biodiversity. About 20 and 80% eukaryotes are aquatics and terrestrials. Decreasing light intensity and temperature reduce diversity from the equator toward the polar zones. Water availability also reduces the diversity from 5.4 - 65.5 species/km2 in tropical evergreen forests to 2 in deserts and polar zones. Unicellularity and radial symmetry decelerate the diversity to 200 in mammals reduce clonality from 100 to 0%. Strategies developed by eukaryotes reduce selfing by
The Protozoan Nucleus Morphology And Evolution
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Author : Igorʹ Borisovich Raĭkov
language : en
Publisher: Springer
Release Date : 1982
The Protozoan Nucleus Morphology And Evolution written by Igorʹ Borisovich Raĭkov and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 1982 with Cell nuclei categories.
Ecology Of Protozoa
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Author : Genoveva F. Esteban
language : en
Publisher: Springer Nature
Release Date : 2021-01-04
Ecology Of Protozoa written by Genoveva F. Esteban and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-01-04 with Science categories.
This book emphasises the important role that protozoa play in many natural ecosystems. To shed new light on their individual adaptive skills, the respective chapters examine the ecology and functional biology of this diverse group of eukaryotic microbes. Protozoa are well-established model organisms that exemplify many general problems in population ecology and community ecology, as well as evolutionary biology. Their particular characteristics, like large population sizes, life cycles and motile sensory behaviour, have a profound impact on their survival, distribution, and interaction with other species. Thus, readers will also be introduced to protozoan habitats in a broad range of environments. Even though this group of unicellular organisms is highly diverse, the authors focus on shared ecological patterns. Students and scientists working in the areas of eukaryotic microbiology and ecology will appreciate this updated and revised 2nd Edition as a valuable reference guide to the “lifestyles” of protozoa.
Endless Forms
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Author : Daniel J. Howard
language : en
Publisher: Oxford University Press, USA
Release Date : 1998
Endless Forms written by Daniel J. Howard and has been published by Oxford University Press, USA this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with Science categories.
Speciation is one of the great themes of evolutionary biology. It is the process through which new species are born and diversity generated. Yet for many years our understanding of the process consisted of little more than a perception that if populations are isolated geographically, they will diverge genetically and may come to form new species. This situation began to change in the 1960s as an increasing number of biologists challenged the exclusivity of allopatric speciation and began to probe more deeply into the actual process by which divergence occurs and reproductive isolation is acquired. This focus on process led to many new insights, but numerous questions remain and speciation is now one of the most dynamic areas of research in modern evolutionary biology. This volume presents the newest research findings on speciation bringing readers up to day on species concepts, modes of speciation, and the nature of reproductive barriers. It also discusses the forces that drive divergence of populations, the genetic control of reproductive isolation, and the role played by hybrid zones and hybridization in speciation.
Evolutionary Biology Of Parasites
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Author : Peter W. Price
language : en
Publisher: Princeton University Press
Release Date : 1980-05-21
Evolutionary Biology Of Parasites written by Peter W. Price and has been published by Princeton University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 1980-05-21 with Science categories.
In spite of the fact that parasites represent more than half of all living species of plants and animals, their role in the evolution of life on earth has been substantially underestimated. Here, for the first time within an evolutionary and ecological framework, Peter Price integrates the biological attributes that characterize parasites ranging from such diverse groups as viruses, bacteria, protozoa, and fungi, to helminths, mites, insects, and parasitic flowering plants. Synthesizing systematics, ecology, behavioral biology, genetics, and biogeography, the author outlines the success of parasitism as a mode of life, the common features of the wide range of organisms that adopt such a way of life, the reasons for parasites' extraordinary potential for continued adaptive radiation, and their role in molding community structure by means of their impact on the evolution of host species. In demonstrating the importance of parasitic interactions for determining population patterns and geographical distributions, Dr. Price generates further discussion and suggests new areas for research.
The Protozoan Nucleus
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Author : Igor B. Raikov
language : en
Publisher: Springer
Release Date : 2014-08-23
The Protozoan Nucleus written by Igor B. Raikov and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-08-23 with Science categories.
A Functional Biology Of Free Living Protozoa
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Author : J.A. Laybourn-Parry
language : en
Publisher: Springer
Release Date : 1984-04-30
A Functional Biology Of Free Living Protozoa written by J.A. Laybourn-Parry and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 1984-04-30 with Science categories.
General Editor: Peter Calow. Department of Zoology. University of Sheffield. England The main aim of this series will be to illustrate and to explain the way organisms 'make a living' in nature. At the heart of this - their func tional biology - is the way organisms acquire and then make use of resources in metabolism, movement, growth, reproduction, and so on. These processes will form the fundamental framework of all the books in the series. Each book will concentrate on a particular taxon (species, family, class or even phylum) and will bring together information on the form, physiology, ecology and evolutionary biology of the group. The aim will be not only to describe how organisms work, but also to consider why they have come to work in that way. By concentrating on taxa which are well known, it is hoped that the series will not only illustrate the success of selection, but also show the constraints imposed upon it by the physiological, morphological and developmentallimita tions of the groups. Another important feature of the series will be its organismic orienta tion. Each book will emphasise the importance of functional integra tion in the day-to-day lives and the evolution of organisms. This is crucial since, though it may be true that organisms can be considered as collections of gene-determined traits, they nevertheless interact with their environment as integrated wholes and it is in this context that individual traits have been subjected to natural selection and have evolved.
A Functional Biology Of Free Living Protozoa
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Author : J.A. Laybourn-Parry
language : en
Publisher: Springer
Release Date : 1984-05-14
A Functional Biology Of Free Living Protozoa written by J.A. Laybourn-Parry and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 1984-05-14 with Science categories.
General Editor: Peter Calow. Department of Zoology. University of Sheffield. England The main aim of this series will be to illustrate and to explain the way organisms 'make a living' in nature. At the heart of this - their func tional biology - is the way organisms acquire and then make use of resources in metabolism, movement, growth, reproduction, and so on. These processes will form the fundamental framework of all the books in the series. Each book will concentrate on a particular taxon (species, family, class or even phylum) and will bring together information on the form, physiology, ecology and evolutionary biology of the group. The aim will be not only to describe how organisms work, but also to consider why they have come to work in that way. By concentrating on taxa which are well known, it is hoped that the series will not only illustrate the success of selection, but also show the constraints imposed upon it by the physiological, morphological and developmentallimita tions of the groups. Another important feature of the series will be its organismic orienta tion. Each book will emphasise the importance of functional integra tion in the day-to-day lives and the evolution of organisms. This is crucial since, though it may be true that organisms can be considered as collections of gene-determined traits, they nevertheless interact with their environment as integrated wholes and it is in this context that individual traits have been subjected to natural selection and have evolved.