Search results for: the-evolution-of-mammalian-characters

The Evolution of Mammalian Characters

Author : D. M. Kermack
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This book is not intended to give a full and comprehensive account of the Mesozoic mammals, and nor is it intended as a handbook for research workers studying pre-Tertiary mammals. Our intention is to give an account of the origin and evolution of certain of the characters of the Mammalia. We have tried to portray the fossils we describe as the living animals they once were, not as dead bones. Our account ends with the end of the Lower Cretaceous, since by that time the major characters of the mammals had become established. There exist a number of characters which, at the present day, are confined to the Mammalia. These include: (1) a jaw articulation formed by the squamosal and the dentary; (2) a chain of three bones, malleus, incus and stapes connecting the tympanic membrane to the inner ear; (3) the presence of hair or fur; (4) the presence of milk-glands in the female; (5) the left aortic arch is the systemic arch; (6) the phalangeal formula in both manus and pes is 2.3.3.3.3; (7) some of the teeth have more than one root. Of these characters (1) or (2) are sufficient by themselves to define a mammal; characters (6) and (7) are known to have been already in existence in some of the mammal-like reptiles - the ancestors of the mammals.

The Origin and Evolution of Mammals

Author : T. S. Kemp
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Mammals are the dominant large animals of today, occurring in virtually every environment. This book is an account of the remarkable 320 million year long fossil record that documents their origin, their long spell as no more than small, nocturnal creatures, and their explosive radiation since the extinction of the dinosaurs 65 million years ago. Tom Kemp also unveils the exciting molecular evidence, which, coupled with important new fossils, is presently challenging current thinking on the interrelationships and historical biogeography of mammals. The Origin and Evolution of Mammals will be of interest to advanced undergraduate and graduate students as well as researchers in vertebrate palaeontology, biogeography, mammalian systematics and molecular taxonomy. It will also be welcomed by vertebrate fossil enthusiasts and evolutionary biologists of all levels with an interest in macroevolutionary problems.

Mammalian Evolutionary Morphology

Author : Eric J. Sargis
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This book celebrates the contributions of Dr. Frederick S. Szalay to the field of Mammalian Evolutionary Morphology. Professor Szalay is a strong advocate for biologically and evolutionarily meaningful character analysis. He has published about 200 articles, six monographs, and six books on this subject. This book features subjects such as the evolution and adaptation of mammals and provides up-to-date articles on the evolutionary morphology of a wide range of mammalian groups.

Cranial Anatomy of Kryptobaatar Dashzevegi Mammalia Multituberculata and Its Bearing on the Evolution of Mammalian Characters Bulletin of the AMNH

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The Origin and Evolution of Mammals

Author : T. S. Kemp
File Size : 85.33 MB
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Mammals are the dominant large animals of today, occurring in virtually every environment. This book is an account of the remarkable 320 million year long fossil record that documents their origin, their long spell as no more than small, nocturnal creatures, and their explosive radiation since the extinction of the dinosaurs 65 million years ago. Tom Kemp also unveils the exciting molecular evidence, which, coupled with important new fossils, is presently challenging current thinking on the interrelationships and historical biogeography of mammals. The Origin and Evolution of Mammals will be of interest to advanced undergraduate and graduate students as well as researchers in vertebrate palaeontology, biogeography, mammalian systematics and molecular taxonomy. It will also be welcomed by vertebrate fossil enthusiasts and evolutionary biologists of all levels with an interest in macroevolutionary problems.

Cranial Anatomy of Kryptobaatar Dashzevegi Mammalia Multituberculata and Its Bearing on the Evolution of Mammalian Characters

Author : John R. Wible
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Amniote Paleobiology

Author : Matthew T. Carrano
File Size : 62.87 MB
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Living amniotes—including all mammals, birds, crocodilians, snakes, and turtles—comprise an extraordinarily varied array of more than 21,000 species. Found in every major habitat on earth, they possess a truly remarkable range of morphological, ecological, and behavioral adaptations. The fossil record of amniotes extends back three hundred million years and reveals much about modern biological diversity of form and function. A collaborative effort of twenty-four researchers, Amniote Paleobiology presents thirteen new and important scientific perspectives on the evolution and biology of this familiar group. It includes new discoveries of dinosaurs and primitive relatives of mammals; studies of mammalian chewing and locomotion; and examinations of the evolutionary process in plesiosaurs, mammals, and dinosaurs. Emphasizing the rich variety of analytical techniques available to vertebrate paleontologists—from traditional description to multivariate morphometrics and complex three-dimensional kinematics—Amniote Paleobiology seeks to understand how species are related to each other and what these relationships reveal about changes in anatomy and function over time. A timely synthesis of modern contributions to the field of evolutionary studies, Amniote Paleobiology furthers our understanding of this diverse group.

Evolutionary History of the Marsupials and an Analysis of Osteological Characters

Author : Frederick S. Szalay
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"This book is the only single-authored, comprehensive volume on the history of marsupials which deals with both the living and extinct groups, and will interest all paleontologists and biologists concerned with mammalian evolution."--BOOK JACKET.

The Evolution of Mammalian Sociality in an Ecological Perspective

Author : Clara B. Jones
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This brief discusses factors associated with group formation, group maintenance, group population structure, and other events and processes (e.g., physiology, behavior) related to mammalian social evolution. Within- and between-lineages, features of prehistoric and extant social mammals, patterns and linkages are discussed as components of a possible social “tool-kit”. "Top-down” (predators to nutrients), as well as “bottom-up” (nutrients to predators) effects are assessed. The present synthesis also emphasizes outcomes of Hebbian (synaptic) decisions on Malthusian parameters (growth rates of populations) and their consequences for (shifting) mean fitnesses of populations. Ecology and evolution (EcoEvo) are connected via the organism’s “norms of reaction” (genotype x environment interactions; life-history tradeoffs of reproduction, survival, and growth) exposed to selection, with the success of genotypes influenced by intensities of selection as well as neutral (e.g. mutation rates) and stochastic effects. At every turn, life history trajectories are assumed to arise from “decisions” made by types responding to competition for limiting resources constrained by Hamilton’s rule (inclusive fitness operations).

Nasal Turbinates and the Evolution of Mammalian Endothermy

Author : Willem J. Hillenius
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Although endothermy is one of the most significant evolutionary developments in the vertebrates, its origins among extinct taxa have traditionally been difficult to determine. Endothermy is primarily an attribute of the "soft anatomy," and its key features, such as complex lungs, elevated blood oxygen carrying capacity and mitochondrial density, do not fossilize. Previously, only one preservable morphological feature, the presence of complex nasal turbinates, has, anecdotally, been considered very suggestive of endothermy in the ancestry of mammals. This thesis examines the functions of the nasal turbinates of extant mammals with respect to physiological characteristics of endothermy. The fossil record of nasal turbinates is also studied. Nasal turbinates serve two distinct functions: olfaction and conditioning of respiratory air. The respiratory turbinates have previously been found to reduce respiratory water loss in desert mammals. Experimental data presented here indicate that these structures also substantially reduce respiratory water loss in non-desert mammals. These data support the conclusion that respiratory turbinates represent an adaptation to reduce desiccation associated with high pulmonary ventilation rates, and may have evolved in association with the origin of elevated ventilation rates and endothermy. Conversely, no particular correlation with endothermy exists for the olfactory turbinates. In extant mammals, the nasal turbinates attach to ridges along the lateral walls of the nasal cavity, which present a characteristic pattern. Studies of similar ridges in the nasal cavities of the ancient mammals and their ancestors, the mammal-like reptiles (Therapsida), indicate that respiratory turbinals first appear in two groups of advanced therapsids, Therocephalia and Cynodontia. This suggests that the evolution of "mammalian" oxygen consumption rates may have begun as early as the Late Permian, 260 million years ago, and developed largely independently in therocephalians and cynodonts. Full mammalian endothermy may have taken as much as 40 to 50 million years to develop.