DOCSLIB.ORG

The Natural Selection of Metabolism Bends Body Mass Evolution in Time

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Natural Selection of Metabolism Bends Body Mass Evolution in Time bioRxiv preprint doi: https://doi.org/10.1101/088997; this version posted November 28, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. ι∗∗=7=3 bioRxiv (2016) 088997 mrLife.org doi:10.1101/088997 a Malthusian Relativity paper The natural selection of metabolism bends body mass evolution in time Lars Witting Greenland Institute of Natural Resources, Box 570, DK-3900 Nuuk, Greenland Abstract I predict a metabolic time bending of body mass clear fusion that emits energy. And energy driven self- evolution in the fossil record. I show that self-replication replication in replicating molecules selects for an in- generates population dynamic feed-back selection for a body creased use of energy in metabolism (Witting 2016a); a mass that increases exponentially on the per generation use that generates net energy for self-replication and ac- time-scale of natural selection, and that this increase is tivates a population dynamic feed-back that selects for driven partly, or fully, by unconstrained selection for an the evolution of large multicellular animals with sexual exponential increase in mass specific metabolism. The in- reproduction (Witting 2016b). In other words, where it crease in metabolism contracts natural selection time; but, mass specific metabolism evolves also by a mass-rescaling is a mass driven force that forms the mass of stars and that generates a partial decline, and time dilation, with an their release of energy; it is suggested that it is energy increase in mass. The overall contraction or dilation of nat- driven self-replication that selects the energy use and ural selection time is bending evolution in physical time, mass of natural organisms. ^ and this is described by an allometry dw=dt wdt for the Although astronomy and evolutionary biology are / rate of evolution in mass (w) in physical time (t). rather unrelated branches of science, the scientific The bending exponent (dt^ ) is shown to evolve from the methods that were used to reveal this ordering of matter relative importance of metabolism for the evolution of mass, and energy in physics and biology were somewhat sim- and from the spatial dimensions of interactive competition ilar. Where gravity enabled Newton (1687) to explain (1D, 2D, 3D); a prediction that is shown to hold across the 3/2 exponent for the Kepler laws of planetary mo- four scale dependent bending exponents in the fossil record. tion around the Sun, the population dynamic feed-back The exponents are i) 3/2 for 2D and 5/3 for 3D evolution selection of energy driven self-replication enabled Wit- within a niche; as observed for horses over 57 million years of evolution. ii) 5/4 (2D) and 9/8 (3D) for the evolution of ting (2016a,b) to explain the evolution of body mass maximum mass across niches; as found in four mammalian allometries in biology; including a shift in the expo- clades across 30 to 64 million years of evolution. iii) 3/4 nent for mass specific metabolism from a positive 5=6 (2D) and 5/6 (3D) for fast body mass evolution; found for in prokaryotes (DeLong et al. 2010) to a negative 1=4 the maximum mass of trunked, and all terrestrial, mam- for Kleiber (1932) scaling in multicellular animals. mals. And iv) 1 for 2D and 3D evolution along a metabolic This ordering of biology is predicted to spring from bound, as observed across 3.5 billion years of evolution of self-replication selection for a mass specific metabolism the maximum mass in non-sessile organisms. that generates net energy for self-replication. This is Keywords: Evolution, metabolism, body mass, time- done by a net resource assimilation that is selected as a bending, life history, allometry, fossil record biochemical/mechanical handling of resource assimila- tion and the speed, or pace, of this process; with pace 1 Introduction being selected as the mass specific work of metabolism. The unconstrained natural selection that follows gen- The aggregation of inert matter in stars and planets, of erate an acceleration of biotic processes, and a steady organic matter in large organisms, and the associated state selection attractor where interactive competition release of energy from stars and use of energy by or- in multicellular animals selects the increase in net en- ganisms, are some of the most striking features of our ergy into an exponentially increasing mass (Witting universe. An understanding of the formation and en- 1997, 2003). ergetics of these bodies is of immense importance for The importance of the metabolic acceleration for this science. evolution of biotic mass is reflected in the body mass al- It is a pull from gravity that first creates stars from lometries, where the exponents are predicted to evolve interstellar molecular clouds and then activates the nu- as a function of the relative importance of the metabolic 1 bioRxiv preprint doi: https://doi.org/10.1101/088997; this version posted November 28, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 2 bioRxiv (2016) 088997 pace for net resource assimilation. Witting (2016a,b) time, and it is larger than one when evolution is bend- describes the natural selection of these allometric cor- ing upward by a contraction of natural selection time. relations across species, and I extend the theory to de- From the −1=4 exponent of Kleiber scaling, where scribe the natural selection conversion of energy into elephants live much longer the mice, we expect biotic organic mass over evolutionary time, by studying body time dilation and a downward bend trajectory (Okie mass allometries as they unfold in time with an evolving et al. 2013). Yet the body mass trajectory of fossil mass. This will provide a base case for the evolution of horses over the past 57 million years is strongly upward metabolism, mass, and major life history and ecological bend with a dt^ exponent of 1.50 (Witting 1997). This traits in multicellular animals over time, and I test the indicates somewhat surprisingly that the lifespan of the theory by predicting body mass trajectories in the fossil horse has declined quite a bit while its mass increased record from first principles. This implies that I will use from about 25 kg to 500 kg over 57 million years of a predicted time-bend of the body mass trajectories to evolution. I will show not only that a 3=2 exponent test for the relative importance of metabolism for the for the horse is likely to have emerged from a body evolution of biotic masses. mass selection that was driven entirely by metabolic acceleration; but more generally that mass evolution 1.1 Time-bend evolution over time can be described as a continuum across four modes of selection, with each mode being supported by The proposed selection predicts an exponential increase a unique bend of the relevant body mass trajectories in in mass on the per generation time-scale of uncon- the fossil record. strained natural selection in a stable environment (Wit- ting 1997, 2003), given evolutionary rates that are in- 1.2 Empirical test of theory variant on the logarithmic scale of metabolism and mass (Witting 2016a,b). This is in agreement with fossil data The basic idea behind my allometric model is popu- where the maximum size of a clade tends to increase lation dynamic feed-back selection that unfolds from in a near-exponential manner during periods of phylo- pre-mass selection for an exponential increase in re- genetic radiation (e.g., Hayami 1978; Trammer 2005; source handling and metabolic pace (Witting 2016a,b). Smith et al. 2010; Okie et al. 2013). And the correla- The resulting increase in resource assimilation gener- tion of evolutionary rates with the per generation time ates population growth with sustained interactive se- scale of natural selection is well documented both for lection for an exponential increase in mass. The in- morphological (Lynch 1990; Gingerich 1993; Okie et al. crease in mass is then imposing selection for a mass- 2013) and molecular traits (Martin and Palumbi 1993; rescaling, where life history traits (x) evolve allometric x^ Gillooly et al. 2005; Nabholz et al. 2008; Galtier et al. correlations with mass xw = w w , wherex ^w is the expo- 2009; Broham 2011). nent and subscript w denotes mass-rescaling. Yet, the The exponential increase generates a log-linear in- evolution of allometries is more complex because the crease of mass over time, but the log-linearity is bend- pre-mass selection for increased metabolism imposes ing in physical time whenever the time-scale of natural a metabolic-rescaling of the life history. This rescal- selection is evolving with the evolutionary changes in ing is transformed into metabolic-rescaling allometries x^ mass (Witting 1997; Okie et al. 2013). A downward (xβ = w β ) by the dependence of body mass evolu- bending is induced when natural selection time is di- tion on the energy that is generated from the pre- lated by a generation time that increases with mass, mass acceleration of metabolic pace (subscript β de- and an upward bending when natural selection time is notes metabolic-rescaling). The final post-mass allome- x^ contracting from a generation time that declines with tries x = w are then products xβxw with exponents mass. x^ =x ^β +x ^w that depend on the relative importance These potential bends are described by an allometry of metabolic acceleration for the evolution of the net energy of the organism.
Load more

Recommended publications
  • The World at the Time of Messel: Conference Volume
    T. Lehmann & S.F.K. Schaal (eds) The World at the Time of Messel - Conference Volume Time at the The World The World at the Time of Messel: Puzzles in Palaeobiology, Palaeoenvironment and the History of Early Primates 22nd International Senckenberg Conference 2011 Frankfurt am Main, 15th - 19th November 2011 ISBN 978-3-929907-86-5 Conference Volume SENCKENBERG Gesellschaft für Naturforschung THOMAS LEHMANN & STEPHAN F.K. SCHAAL (eds) The World at the Time of Messel: Puzzles in Palaeobiology, Palaeoenvironment, and the History of Early Primates 22nd International Senckenberg Conference Frankfurt am Main, 15th – 19th November 2011 Conference Volume Senckenberg Gesellschaft für Naturforschung IMPRINT The World at the Time of Messel: Puzzles in Palaeobiology, Palaeoenvironment, and the History of Early Primates 22nd International Senckenberg Conference 15th – 19th November 2011, Frankfurt am Main, Germany Conference Volume Publisher PROF. DR. DR. H.C. VOLKER MOSBRUGGER Senckenberg Gesellschaft für Naturforschung Senckenberganlage 25, 60325 Frankfurt am Main, Germany Editors DR. THOMAS LEHMANN & DR. STEPHAN F.K. SCHAAL Senckenberg Research Institute and Natural History Museum Frankfurt Senckenberganlage 25, 60325 Frankfurt am Main, Germany [email protected]; [email protected] Language editors JOSEPH E.B. HOGAN & DR. KRISTER T. SMITH Layout JULIANE EBERHARDT & ANIKA VOGEL Cover Illustration EVELINE JUNQUEIRA Print Rhein-Main-Geschäftsdrucke, Hofheim-Wallau, Germany Citation LEHMANN, T. & SCHAAL, S.F.K. (eds) (2011). The World at the Time of Messel: Puzzles in Palaeobiology, Palaeoenvironment, and the History of Early Primates. 22nd International Senckenberg Conference. 15th – 19th November 2011, Frankfurt am Main. Conference Volume. Senckenberg Gesellschaft für Naturforschung, Frankfurt am Main. pp. 203.
    [Show full text]
  • Unit-V Evolution of Horse
    UNIT-V EVOLUTION OF HORSE Horses (Equus) are odd-toed hooped mammals belong- ing to the order Perissodactyla. Horse evolution is a straight line evolution and is a suitable example for orthogenesis. It started from Eocene period. The entire evolutionary sequence of horse history is recorded in North America. " Place of Origin The place of origin of horse is North America. From here, horses migrated to Europe and Asia. By the end of Pleis- tocene period, horses became extinct in the motherland (N. America). The horses now living in N. America are the de- scendants of migrants from other continents. Time of Origin The horse evolution started some 58 million years ago, m the beginning of Eocene period of Coenozoic era. The modem horse Equus originated in Pleistocene period about 2 million years ago. Evolutionary Trends The fossils of horses that lived in different periods, show that the body parts exhibited progressive changes towards a particular direction. These directional changes are called evo- lutionary trends. The evolutionary trends of horse evolution are summarized below: 1. Increase in size. 2. Increase in the length of limbs. 3. Increase in the length of the neck. 4. Increase in the length of preorbital region (face). 5. Increase in the length and size of III digit. 6. Increase in the size and complexity of brain. 7. Molarization of premolars. Olfactory bulb Hyracotherium Mesohippus Equus Fig.: Evolution of brain in horse. 8. Development of high crowns in premolars and molars. 9. Change of plantigrade gait to unguligrade gait. 10. Formation of diastema. 11. Disappearance of lateral digits.
    [Show full text]
  • Skeleton of the Oligocene (30 Million-Year-Old) Horse, Mesohippus, Is a Featured Exhibit at the New North Dakota Cowboy Hall of Fame in Medora
    Skeleton of the Oligocene (30 million-year-old) horse, Mesohippus, is a featured exhibit at the new North Dakota Cowboy Hall of Fame in Medora By John W. Hoganson Developers of the recently opened North Dakota Cowboy Hall of Fame contacted me about having a fossil exhibit in the new Hall in Medora. Of course, what would be more appropriate than an exhibit interpreting the evolution of the horse? Most people are under the false impression that horses did not inhabit North America until they were introduced by the Spaniards during the early days of conquest. But horses are indigenous to North America. Fossil remains of the earliest horse, referred to as Hyracotherium (or sometimes Eohippus), have been recovered from early Eocene (about 50 million years old) rocks in North America. In fact, they were some of the most abundant mammals that lived during that time. The fossil record of horses in North Dakota extends back to the Oligocene, about 30 million years ago, when the diminutive horse, Mesohippus roamed western North Dakota. Mesohippus was tiny, about the size of a sheep. The adults were only about 20 inches tall at the shoulder. They also had three toes on each foot compared to the modern horse Equus that has one. Mesohippus was also probably more of a browsing herbivore compared to the modern grazing horse. We have found many Mesohippus fossils in North Dakota but no complete skeletons. Consequently, the Mesohippus skeleton on exhibit at the Cowboy Hall of Fame is an exact cast replica. We have also found the remains of 50,000-year-old horses in North Dakota indicating that horses lived here during the last Ice Age.
    [Show full text]
  • Scale-Dependence of Cope's Rule in Body Size Evolution of Paleozoic
    Scale-dependence of Cope’s rule in body size evolution of Paleozoic brachiopods Philip M. Novack-Gottshall* and Michael A. Lanier Department of Geosciences, University of West Georgia, Carrollton, GA 30118-3100 Edited by Steven M. Stanley, University of Hawaii at Manoa, Honolulu, HI, and approved January 22, 2008 (received for review October 10, 2007) The average body size of brachiopods from a single habitat type volume) for 369 adult genera [see supporting information (SI) increased gradually by more than two orders of magnitude during Appendix, Tables 1 and 2] from deep-subtidal, soft-substrate their initial Cambrian–Devonian radiation. This increase occurred habitats demonstrates that brachiopod body size increased sub- nearly in parallel across all major brachiopod clades (classes and stantially and gradually during the Early and Mid-Paleozoic (Fig. orders) and is consistent with Cope’s rule: the tendency for size to 1), from a Cambrian mean of 0.04 ml (Ϫ1.40 log10 ml Ϯ 0.27 SE, increase over geological time. The increase is not observed within n ϭ 18 genera) to a Devonian mean of 1.55 ml (0.19 log10 ml Ϯ small, constituent clades (represented here by families), which 0.06, n ϭ 150). The magnitude of size increase between periods underwent random, unbiased size changes. This scale-dependence is statistically significant. We evaluated within-phylum dynamics is caused by the preferential origination of new families possessing by using maximum-likelihood comparisons among three evolu- initially larger body sizes. However, this increased family body size tionary models: directional (driven, biased, general random does not confer advantages in terms of greater geological duration walk) change (DRW), unbiased (passive) random walk (URW), or genus richness over families possessing smaller body sizes.
    [Show full text]
  • Paleobiology of Archaeohippus (Mammalia; Equidae), a Three-Toed Horse from the Oligocene-Miocene of North America
    PALEOBIOLOGY OF ARCHAEOHIPPUS (MAMMALIA; EQUIDAE), A THREE-TOED HORSE FROM THE OLIGOCENE-MIOCENE OF NORTH AMERICA JAY ALFRED O’SULLIVAN A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2002 Copyright 2002 by Jay Alfred O’Sullivan This study is dedicated to my wife, Kym. She provided all of the love, strength, patience, and encouragement I needed to get this started and to see it through to completion. She also provided me with the incentive to make this investment of time and energy in the pursuit of my dream to become a scientist and teacher. That incentive comes with a variety of names - Sylvan, Joanna, Quinn. This effort is dedicated to them also. Additionally, I would like to recognize the people who planted the first seeds of a dream that has come to fruition - my parents, Joseph and Joan. Support (emotional, and financial!) came to my rescue also from my other parents—Dot O’Sullivan, Jim Jaffe and Leslie Sewell, Bill and Lois Grigsby, and Jerry Sewell. To all of these people, this work is dedicated, with love. ACKNOWLEDGMENTS I thank Dr. Bruce J. MacFadden for suggesting that I take a look at an interesting little fossil horse, for always having fresh ideas when mine were dry, and for keeping me moving ever forward. I thank also Drs. S. David Webb and Riehard C. Hulbert Jr. for completing the Triple Threat of Florida Museum vertebrate paleontology. In each his own way, these three men are an inspiration for their professionalism and their scholarly devotion to Florida paleontology.
    [Show full text]
  • Florida Fossil Horse Newsletter
    Florida Fossil horse Newsletter Volume 10, Number 1, 1st Half 2001 What's Inside? Fossil Horses On the Road: Archaeohippus and Parahippus Check Out the Bluegrass State Meet Our Artists Volunteers Help the Museum While Enhancing Their Own Education Thunderbeasts, Sexual Selection and Extinction Skeleton "Under Construction" Homeschooling Groups Request More Family Days at Thomas Farm Book Review - The Fossil Vertebrates of Florida Introducing A New Logo For Pony Express's 10th Anniversary Fossil Horses On the Road: Archaeohippus and Parahippus Check Out the Bluegrass State Lexington, Kentucky welcomed Miocene horses at a special event at the Lexington Children's Museum, March 3, 2001. Loaned by the Florida Museum of Natural History, many fossils of the two small prehistoric horses from Thomas Farm are being displayed at the Children's Museum through March and April. Touchable casts of the skulls and feet are also charming the kids, who think the "little horses" are just awesome. At the all-day fossil event, a large display was set up with a case for some of the more fragile horse Seth Woodring, 3, of Winchester, made himself a plaster "fossil" with some help from his mother, fossils. Three Beth, and 5-year-old sister, Rayne. David Stephenson photo (reprinted with permission from tables held fossil Herald Leader) bones and casts, with modern horse bones for comparison. Experts Dr. Teri Lear and Dr. Lenn Harrison, with the Department of Veterinary Science at the University of Kentucky, presented Archaeohippus and Parahippus to the public. Teri has participated in several digs at Thomas Farm, and talked with visitors about the Miocene digs and fossils.
    [Show full text]
  • Bruce J. Macfadden*
    MacFadden, B.J., 2006, Early Pliocene (latest Hemphillian) horses from the Yepómera Local 33 Fauna, Chihuahua, Mexico, in Carranza-Castañeda, Óscar, and Lindsay, E.H., eds., Advances in late Tertiary vertebrate paleontology in Mexico and the Great American Biotic Interchange: Universidad Nacional Autónoma de México, Instituto de Geología and Centro de Geociencias, Publicación Especial 4, p. 33–43. EARLY PLIOCENE (LATEST HEMPHILLIAN) HORSES FROM THE YEPÓMERA LOCAL FAUNA, CHIHUAHUA, MEXICO Bruce J. MacFadden* ABSTRACT The latest Hemphillian (Hh4) is characterized by a distinctive equid assemblage, four spe- cies of which are widespread in North America. One of the largest collections of Hh4 equids is from Yepómera, located in Chihuahua, Mexico. Although Yepómera is actually a series of sub-localities, the equids are morphologically similar from each of these and therefore can be considered as a local faunal assemblage of four sympatric species. The distinctive dental patterns, size of the cheek teeth, and (in most cases) metapodial dimensions, make these horses readily distinguishable in the field. Yepómera equids include the monodactyl Astrohippus stockii and Dinohippus mexicanus, and tridactyl Neohipparion eurystyle and Nannippus aztecus. Yepómera is the type locality for the species A. stockii and D. mexica- nus, both described by Lance in 1950. Neohipparion eurystyle and the genus Neohipparion and A. stockii and the genus Astrohippus become extinct at the end of Hh4. Nannippus aztecus is a sister taxon of later Nannippus and D. mexicanus is the sister taxon of Equus, the equid genera that survived in North America during the Plio-Pleistocene. With hypsodonty indices between 2.6 and 3.7, all of the Yepómera horse species have high-crowned teeth, traditionally interpreted as a grazing adaptation.
    [Show full text]
  • Horse Evolution ‐ Extended for the Classroom ‐
    Horse Evolution ‐ Extended for the Classroom ‐ GRADE LEVELS • 5‐8 TIME • 30‐40 minutes LEARNING OBJECTIVES • Environmental pressures can cause small changes in an animal’s physiology. • These small changes are called adaptations. • The accumulation of these small changes over time can drastically change an animal. This is known as evolution. MATERIALS • Air dry clay • Horse feet models • Large ink pads • Warm soap and water (for clean up) BACKGROUND INFORMATION • The first horse ancestor, Eohippus, appeared in North America 60 million years ago. • Changes in the environment over time led to changes in the horses’ anatomy, especially the hoof. • These adaptations caused by environmental pressures are integral in the evolution of the horse. Darwin2009: Partnership for Education – www.sepa.duq.edu/darwin SET UP 1. On a large flat table, display the 4 horse feet models. 2. Before class starts, separate the clay into balls (about the size of a baseball). 3. Have the ink pads close by the horse feet models. INTRODUCTION 1. Have students gather around the table and introduce the activity. Encourage the students to study the horse feet: a. What are some of the differences between the feet? b. What do you think the environment was like? c. Can you guess how old is the oldest skeleton? d. How do you imagine the horse behaved then and now? For example, what would the ancient horse do if he saw a predator (probably hide), versus the modern horse (probably run). 2. Point out the marked difference in the feet of the horses. The feet of the horses provide great insight into how the horse has evolved.
    [Show full text]
  • Stratigraphy, Petrology, and Paleontology of the Late Cretaceous Campanian Mesaverde Group in Northeastern Utah
    Utah State University DigitalCommons@USU All Graduate Plan B and other Reports Graduate Studies 8-2017 Stratigraphy, Petrology, and Paleontology of the Late Cretaceous Campanian Mesaverde Group in Northeastern Utah Christopher Ward Follow this and additional works at: https://digitalcommons.usu.edu/gradreports Part of the Geology Commons, Paleontology Commons, and the Sedimentology Commons Recommended Citation Ward, Christopher, "Stratigraphy, Petrology, and Paleontology of the Late Cretaceous Campanian Mesaverde Group in Northeastern Utah" (2017). All Graduate Plan B and other Reports. 1049. https://digitalcommons.usu.edu/gradreports/1049 This Report is brought to you for free and open access by the Graduate Studies at DigitalCommons@USU. It has been accepted for inclusion in All Graduate Plan B and other Reports by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. Utah State University DigitalCommons@USU All Graduate Plan B and other Reports Graduate Studies Fall 8-10-2017 Stratigraphy, Petrology, and Paleontology of the Late Cretaceous (Campanian) Mesaverde Group in Northeastern Utah Christopher Ward Follow this and additional works at: http://digitalcommons.usu.edu/gradreports Part of the Geology Commons, Paleontology Commons, and the Sedimentology Commons This Report is brought to you for free and open access by the Graduate Studies at DigitalCommons@USU. It has been accepted for inclusion in All Graduate Plan B and other Reports by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. STRATIGRAPHY, PETROLOGY, AND PALEONTOLOGY OF THE LATE CRETACEOUS (CAMPANIAN) MESAVERDE GROUP IN NORTHEASTERN UTAH By Christopher J. Ward A report submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Applied Environmental Geoscience Approved: ____________________ __________________ Benjamin J.
    [Show full text]
  • Neohipparion, a Three-Toed Horse by CHESTER STOCK
    Neohipparion, A Three-Toed Horse By CHESTER STOCK 0 other lineage of mammal-' illustrates quite so are elevated above the ground and no longer function clearly or so full$ its growth or evolution in geo- a supporting elements of the foot. In the retention of Nlogic time as that of the horse. In the history of the the lateral digits the hipparions were distinctly less pro- Equidae many forms antecedent to the living animal are gressive than the contemporary and monodactyl Pliohip- now known, each marked by readily identifiable charac- pus, and it is from the latter that Equu~is now regarded ters in the teeth, skull and skeleton. From Eohippus, to have sprung. the "dawn horse" of approximately 50 million years The hipparion group persisted through the Pliocene, ago, to the equines of today, a score or more different hut disappeared with the coming of the Pleistocene or kind3 of genera and numerous species of extinct horse* Ice Age, at least in North America. During the late have been described. The changes that have produced Miocene or early Pliocene. the true hipparions are found the large and specialized animal of today from the in North America and Eurasia. By the middle of this diminutive and distinctly less specialized Eocene ancestor epoch. perhaps eight or nine millions of years ago. these of long ago are demonstrated by an amazing array of horses gave ua; to the larger. heavier neohipparions fossil remains. fonnd for the most part in the land-laid which were characteristically North American in distri- formations of the western United States.
    [Show full text]
  • The Evolution of Occlusal Enamel Complexity in Middle
    THE EVOLUTION OF OCCLUSAL ENAMEL COMPLEXITY IN MIDDLE MIOCENE TO RECENT EQUIDS (MAMMALIA: PERISSODACTYLA) OF NORTH AMERICA by NICHOLAS ANTHONY FAMOSO A THESIS Presented to the Department of Geological Sciences and the Graduate School of the University of Oregon in partial fulfillment of the requirements for the degree of Master of Science June 2013 THESIS APPROVAL PAGE Student: Nicholas Anthony Famoso Title: The Evolution of Occlusal Enamel Complexity in Middle Miocene to Recent Equids (Mammalia: Perissodactyla) of North America This thesis has been accepted and approved in partial fulfillment of the requirements for the Master of Science degree in the Department of Geological Sciences by: Dr. Edward Davis Chair Dr. Qusheng Jin Member Dr. Stephen Frost Outside Member and Kimberly Andrews Espy Vice President for Research & Innovation/Dean of the Graduate School Original approval signatures are on file with the University of Oregon Graduate School. Degree awarded June 2013 ii © 2013 Nicholas Anthony Famoso iii THESIS ABSTRACT Nicholas Anthony Famoso Master of Science Department of Geological Sciences June 2013 Title: The Evolution of Occlusal Enamel Complexity in Middle Miocene to Recent Equids (Mammalia: Perissodactyla) of North America Four groups of equids, “Anchitheriinae,” Merychippine-grade Equinae, Hipparionini, and Equini, coexisted in the middle Miocene, and only the Equini remains after 16 million years of evolution and extinction. Each group is distinct in its occlusal enamel pattern. These patterns have been compared qualitatively but rarely quantitatively. The processes controlling the evolution of these occlusal patterns have not been thoroughly investigated with respect to phylogeny, tooth position, and climate through geologic time. I investigated two methods of quantitative analysis, Occlusal Enamel Index for shape and fractal dimensionality for complexity.
    [Show full text]
  • Mammalian Faunal Change During the Early Eocene Climatic
    MAMMALIAN FAUNAL CHANGE DURING THE EARLY EOCENE CLIMATIC OPTIMUM (WASATCHIAN AND BRIDGERIAN) AT RAVEN RIDGE IN THE NORTHEASTERN UINTA BASIN, COLORADO AND UTAH by ALEXANDER R. DUTCHAK B.Sc., University of Alberta, 2002 M.Sc., University of Alberta, 2005 A thesis submitted to the Faculty of the Graduate School of the University of Colorado in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Geological Sciences 2010 This thesis entitled: Mammalian faunal change during the Early Eocene Climatic Optimum (Wasatchian and Bridgerian) at Raven Ridge in the northeastern Uinta Basin, Colorado and Utah written by Alexander R. Dutchak has been approved for the Department of Geological Sciences ______________________________ Jaelyn J. Eberle (Supervisor) ______________________________ John Humphrey ______________________________ Mary Kraus ______________________________ Tom Marchitto ______________________________ Richard Stucky Date: ________________________ The final copy of this thesis has been examined by the signatories, and we find that both the content and the form meet acceptable presentation standards of scholarly work in the above mentioned discipline. ABSTRACT Dutchak, Alexander R. (Ph.D., Geological Sciences, Department of Geological Sciences) Mammalian faunal change during the Early Eocene Climatic Optimum (Wasatchian and Bridgerian) at Raven Ridge in the northeastern Uinta Basin, Colorado and Utah Thesis directed by Assistant Professor Jaelyn J. Eberle This project investigated patterns of mammalian faunal change at Raven Ridge, which straddles the Colorado-Utah border on the northeastern edge of the Uinta Basin and consists of intertonguing units of the fluvial Colton and lacustrine Green River Formations. Fossil vertebrate localities comprising >9,000 fossil mammal specimens from 62 genera in 34 families were identified and described.
    [Show full text]