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Paper Abstract: Describes the evolutionary development of horses. Evidence obtained from fossil records that supports the anagenetic view of horse phylogeny as well as cladogenetic pattern. Fossil record as a clasic example of macroevolution. Branching speciation. Support of the view that a gradual microevolutionary process occurred within the species. Focuses on the North American Eocene and Oligocene fossil records. Paper Introduction: A Cladogenetic View of the Early Evolutionary History of Horses Abstract Drawing upon the theoretical and empirical literature, this report describes the evidence obtained from the fossil record that supports the anagenetic view of the horse phylogeny and its early evolutionary development. The anagenetic perspective advances the notion that a gradual microevolutionary process has occurred within a species. It is also associated with phyletic transformation from ancestral to descendant species. The fossil record for horses presents, in general, a progressive replacement of one genus with another without a strong indication of temporary overlapping. However, the literature also suggests that anagenetic development was dominant within the Eocene and Oligocene, while genetic diversity (branching) suggesting a Text of the Paper: The entire text of the paper is shown below. However, the text is somewhat scrambled. We want to give you as much information as we possibly can about our papers and essays, but we cannot give them away for free. In the text below you will find that while disordered, many of the phrases are essentially intact. From this text you will be able to get a solid sense of the writing style, the concepts addressed, and the sources used in the research paper. record that supports theanagenetic view of the fossil record for horses presents and Oligocene whilegenetic diversity branching suggesting AmericanEocene and Oligocene fossil records Both periods of horses family Equidae over the that any given fossillocality in North America from about to variousenvironments and ways of life the view of many professionals is that acladogenetic or branching diversity and numbers ofspecies The and the Oligocene with specific reference to Miohippus and paleontologists named an average of three new species course of the twentieth century the and linear in terms of evolution in different branches of the family was beidentified in the fossil record He also suggests that two major modes of species descendant species Cladogenesis orbranching as opposed to phyletic speciation achieved prominencebecause of what MacFadden characterizes by transformational change within populationsrather than by theadaptive radiation of hypsodont forms the pattern was decidedlycladogenetic claimed that it was only at a comparatively lateepoch in the Perissodactyles the earliest ancestralforms of Ridgeway believes that in pre-glacial times North conquest Fewsatisfactory explanations for this one or more predators Another theory states that at the beginning Pocket in south-central Coloradoprovides evidence of two disparate species continued throughout the Oligocene and Miocene that recent work has elucidated the species-level systematics of middle-Miocene with cladogenetic evolution MacFadden identified thekey morphological Eocene Increased ratio of brain size to Recent apparatus MacFadden p At the beginning Miohippus The latter two were much SouthDakota and adjacent states Most significantly in facial and bodyproportions muzzlewas lengthened and a larger gap between the the eye Hulbert also points out Desmatippus alongwith Parahippus and Archaeohippus had all North America Theanchitheres retained the low-crowned relatively simple teeth and significant cladogenetic branching took place in numerous clades with high-crowned and evolution MacFadden also believes that the fossil record tooth-crown height This suggests that evolved in partbecause of the existence of new food controversial conclusion MacFadden believes that the coexistence of so many rapidly to include largespecies and even a few a linear progression in terms ofdevelopment Miocene to occur MacFadden is convinced that the advent years ago horse diversity dropped the Northern Hemisphere A combination ofnatural climate have affected horse diversity As of diversified rapidly between and million years ago Nevertheless the great diversity of species in the fossil record is said to have been responsible for theextinction of four the late Miocene Each of these events speaks Summary and Conclusions The purpose of this anagenetic orprogressing in a virtually straight single line of on the evolutionary trunk This discussion not only to paleontologists and newinvestigative technologies established theories of necessity joke Natural History Hulbert R of horses Natural History MacFadden Influence of the ThoroughbredHorse New York Benjamin upon the theoretical and empirical literature this reportdescribes the within a species It is alsoassociated with overlapping However the literature also from the second half ofhorse simple anagenetic progressionof genera from Mesohippus to Miohippus representing a across thecontinent have been identified as livedside-by-side However from about million years ago as many as a dozen species have been Miocene Hulbert Earlier MacFadden and Simpson thisreport to draw upon the literature and Cladogenesis Hulbert states that paleontologists have been analyzing vogue andthen falling by the wayside as new fossil like George Gaylord Simpson arguedthat the definitivepattern of steady change from four to three and totally random process He argued also influenced this evolutionaryprocess Simpson MacFadden moves forward from anagenesis as associated with macroevolution Simpson and other early paleontologists evolution Gould claims that Simpson held a the fossil record it is becoming increasinglyobvious that during the inthe late Eocene and continuing into and beyond the to occur in the Tertiary period abundantly in deposits of the most recent varied significantly in size butdisappeared from America their evolutionary tether in the attainment of which may most probably have horses known as hyracotheresappeared in the faunas of North America the directconnection between North America and Europe history and became increasinglyadapted for living in open habitats patterns of an importantadaptive radiation What occurred Table I Key Morphological Characters cheek Recent teeth springing foot newtypes of horses appeared in North America These that we have a wealth of evidence from was lost andthere were three toes known as a facial fossa were present on the cladogenetic branching can be observed By the the late Oligocene Miohippus two a body weight of to kilograms Ultimately horses in the North Americanfossil record relates to diet Fossil interpreted diet of extinct horses is awidely compares different fossil recordsor equid clades found the fossil recordand stated that the teeth high-crowned teeth in horses represented anirreversible divided up the niches and resources available to them It descendant species beinglarger on average than their ancestors the fossil occupying severaldifferent niches Clearly this supports the idea zone A multitude of evolutionary changes through branching anddiversification ultimately a return to pre-Miocene levels of only three to the end ofbranching Additionally competition with cud-chewing Northern Hemisphere Hulbert states that evolving from a common fossil record notwithstanding it was Equus which would and the Old World the advent of more species in the second event Hulbert cladogenetic process of evolution was on the topic For many years paleontologists held that have found evidence supporting a cladogeneticevolutionary pattern in of thecladogenetic interpretation It also demonstrates that as the researchers such as Hulbertand MacFadden References MacFadden B J Fossil Horses V Dietary data straight from A Cladogenetic View of the horse phylogeny and its early evolutionarydevelopment The anagenetic perspective in general a progressivereplacement of one genus a cladogenetic developmentalpattern can be are considered to be atime of past millionyears is a classic example of macroevolution MacFadden NorthAmerica million years ago itis usually MacFadden also says that horsediversity increased so dramatically speciation took place during the Eocene andcontinued into the fossil record says MacFadden is an excellent mediumfor andMesohippus Such an examination will demonstrate that from the of fossil horses peryear Many palentological interpretations are controversial withcontending trail of horseevolution has followed what Hulbert calls a evolutionary pattern There was saysSimpson no not revealed as anorthogenetic process in the fossil parallel andconvergent evolution took place simultaneously evolution and thespeciation process generally interpreted is the dominant mode ofspeciation in rapidly evolving clades particularly as its importance insystematic methodologies and evolutionary by accumulation across numerous events of discrete branchingspeciation Thus the following discussion will reflect a the history of mammals that the ancestors the horses and tapirs of today can America possessed at least nine disappearance have been offered thoughRidgeway makes reference to is that an infestationof parasites of various types may of the Eocene epoch about one larger and one smaller Atthe end of the periods Hulbert says that at this juncture North American horse phylogeny and been responsiblefor characters recognized within the evolution of the familyEquidae body size and expanded neocortex Mesohippus of the late Eocene contemporary moreadvanced than the Haplohippus and are Mesohippus and Miohippus had much more classic horse-likefeatures than older anterior nipping teeth orincisors and the that Miohippus was the genera emerged Of these groups it wasfrom Anchitherium that the paddedfeet of Miohippus but reached a considerable size Hulbert MacFadden has suggested that one of the critical teeth forgrazing on abrasive plants particularly grasses The connection supports varied patterns infood consumption ranging from grazing to browsers fairly significantcladogenetic branching was in fact taking place However when the species switchedback to eating browse the species ofsimilar ancestry and general dwarf lineages Contrary to Cope's Rule in whichan increase in horses says MacFadden appear to of hypsodonty high-crowned dentition in Miocene dramatically MacFadden identifies the fossil changes leading to increased global aridity and lessproductive twomillion years ago only the single with hipparionine horses predominating in North Americanfaunas hasconvinced paleontologists that cladogenetic branching was going on apace inthis genera and ten species of further to thequestion of what kind of report was to examine a specific evolutionarytopic and evolution Morerecently as the work serves to explicate the thesis advanced inthe outset of the requirerevision Simpson's seminal work in this field is C The ancestry of the horse B J Ancient diets ecology and extinction of million-year-old Blom Simpson G G Horses New York Oxford evidence obtained from the fossil phyletic transformation from ancestral to descendantspecies The suggests thatanagenetic development was dominant within the Eocene development The report focuses therefore on the North single trunk of thephylogenetic tree Introduction The fossil record containing abundant remains of ancientmembers of the family MacFadden states ago the fossilrecord suggests that horses evolved rapidly adapting to found What this suggests in agree that an anagenetic macroevolutionarytransformation took place leading to limited to examine the fossil record from thelate Eocene theequid fossil record for well over years Between evidence is uncovered Throughout the evolution of the horse family was definitely not orthogenetic orstraight finally one toe Foot andtoe thata distinct process known as transformation leading to specialization can the work of Simpson anddifferentiates between the or phyletictransformation from ancestral to did discusscladogenesis it is only recently that cladogenesis has life long commitment to thepredominant role of evolution second half of horse evolution represented Oligocene The Emergence of Speciated Branching Ridgeway has With two extinct families of geological agein almost every part of America and at the time of the Spanish speed these horsesfell prey to crossed into Asia prior tosuch an infestation Hulbert and Eurasia Evidence obtainedfrom the fossil record at Costillo and major climatic changesbegan which and for running MacFadden believes was precisely the kind of branching thatis associated Family Equidae Age Key CharacterTaxonHyracotherium Equus Pliocene Evolution of the passive stay are the generaHaplohippus Mesohippus and theincredibly fossilferous rocks of late-Eocene and Oligocene age in on both the forefoot and hindfoot The skull side of theskull in front of the opening for early Miocene Kalobatippus Anchitherium and main lines ofdescent are recognized from the early Miocene of itwas the Equinae in which horses underwent an explosiveadaptive radiation resulting accepted model of long-term adaptation across North America one finds enormous simultaneousvariations in of ancient equines may have evolutionary change though Morell points out that thisis a somewhat was during the Miocene that horses diversified record of the Miocenesuggests that species size was not that a cladogeneticpattern of evolution was beginning resulted in the emergence of Equus Startingabout eight million five species atany given fossil locality in hoofed herbivores e g deer and bison may also ancestor three-toed hipparionine and equine horses eventually assume primacy among all horse species a new climaticphase in the late Miocene period Only three horse species survived eliminating the maximum diversityobserved in occurring during theera under discussion herein theevolution of horses as evident in the fossil record was the Miocene which created a multiplicity of horsespecies or branches fossil recordyields more and more of its secrets Gould S J Life's little Cambridge CambridgeUniversity Press MacFadden B J The heyday the horse's mouth Science Ridgeway W The Origin and Early Evolutionary History of Horses Abstract Drawing advances the notion that a gradualmicroevolutionary process has occurred with another without a strong indication oftemporary observed from the fossil record low equine diversity depicted as a is the ancestral home of horses and many fossil sites possible to find species of horses that seem to have that at some fossil sites from million years Oligocene with rapid diversification becomingcharacteristic of the early examining both anagenesis and cladogenesis It is the purpose of Oligoceneperiod on cladogenetic evolution of the horse was occurring DiscussionAnagenesis and alternative hypotheses and theories coming into two-track system Onthe one hand paleontologists constant and overall increase in size or a record Simpson also rejectedthe idea that horse evolution was a and that selected quantumshifts involving adaptive relationships from the fossil record Hedefines during an adaptiveradiation MacFadden While models MacFadden departsfrom Simpson by emphasizing cladogenetic However MacFadden has successfully argued that despitethe inherent limitations of cladogeneticbranching pattern in the North American equine fossil record beginning of the horse made theirfirst appearance Hoofed animals began be observed Fossil remains ofhorses are found perfectly distinctwild species of Equidae These species the possibility that after coming to theend of have led to the extinction of the NorthAmerican Equidae million years ago tiny dawn early Eocene the continental drift severed horses took adifferent course in their evolutionary a revised interpretation of the evolutionary The following table presents these characters Miohippus Oligocene Molarized premolars tridactyl feetEquinae Miocene Cement-covered high-crowned paleontologists including Hulbert and MacFadden state that three among the best known of the fossilhorses Hulbert claims genera The fifth digit of the forefoot posterior chewing teeth had developed A distinctdepression or pit fromwhich the most striking example of ancestors of Equus were identified Originating from comparable to modernEquus and achieving explanationsfor the evolutionary pattern observed in betweenobserved tooth crown height and with correspondingshifts in tooth-crown height When one during this evolutionaryperiod Morell has summarized recent evidence from teeth did not change MacFadden suggested that the emergence of adaptive traits in the same ecosystemssuggests that horses body size over time results in haveminimized competition for available food and space by horses allowed them to invade a newadaptive record from this time presenting aportrait of land ecosystems is generally associated with horse genus Equus consisting of a fewspecies remained in the Their numerical superiority in the particular era In both the New World horses in the first event andfour more genera and six evolutionary process was at work and supports theassertion that a to draw upon the literature to identify current thinking andresearch of Hulbert and MacFadden demonstrates paleontologists report with respect to the appropriateness thereforeaugmented and expanded by that of contemporary HorsesThrough Time New York Roberts Rinehart horses from Florida Science Morell University Press record that supports theanagenetic view of the fossil record for horses presents and Oligocene whilegenetic diversity branching suggesting AmericanEocene and Oligocene fossil records Both periods of horses family Equidae over the that any given fossillocality in North America from about to variousenvironments and ways of life the view of many professionals is that acladogenetic or branching diversity and numbers ofspecies The and the Oligocene with specific reference to Miohippus and paleontologists named an average of three new species course of the twentieth century the and linear in terms of evolution in different branches of the family was beidentified in the fossil record He also suggests that two major modes of species descendant species Cladogenesis orbranching as opposed to phyletic speciation achieved prominencebecause of what MacFadden characterizes by transformational change within populationsrather than by theadaptive radiation of hypsodont forms the pattern was decidedlycladogenetic claimed that it was only at a comparatively lateepoch in the Perissodactyles the earliest ancestralforms of Ridgeway believes that in pre-glacial times North conquest Fewsatisfactory explanations for this one or more predators Another theory states that at the beginning Pocket in south-central Coloradoprovides evidence of two disparate species continued throughout the Oligocene and Miocene that recent work has elucidated the species-level systematics of middle-Miocene with cladogenetic evolution MacFadden identified thekey morphological Eocene Increased ratio of brain size to Recent apparatus MacFadden p At the beginning Miohippus The latter two were much SouthDakota and adjacent states Most significantly in facial and bodyproportions muzzlewas lengthened and a larger gap between the the eye Hulbert also points out Desmatippus alongwith Parahippus and Archaeohippus had all North America Theanchitheres retained the low-crowned relatively simple teeth and significant cladogenetic branching took place in numerous clades with high-crowned and evolution MacFadden also believes that the fossil record tooth-crown height This suggests that evolved in partbecause of the existence of new food controversial conclusion MacFadden believes that the coexistence of so many rapidly to include largespecies and even a few a linear progression in terms ofdevelopment Miocene to occur MacFadden is convinced that the advent years ago horse diversity dropped the Northern Hemisphere A combination ofnatural climate have affected horse diversity As of diversified rapidly between and million years ago Nevertheless the great diversity of species in the fossil record is said to have been responsible for theextinction of four the late Miocene Each of these events speaks Summary and Conclusions The purpose of this anagenetic orprogressing in a virtually straight single line of on the evolutionary trunk This discussion not only to paleontologists and newinvestigative technologies established theories of necessity joke Natural History Hulbert R of horses Natural History MacFadden Influence of the ThoroughbredHorse New York Benjamin upon the theoretical and empirical literature this reportdescribes the within a species It is alsoassociated with overlapping However the literature also from the second half ofhorse simple anagenetic progressionof genera from Mesohippus to Miohippus representing a across thecontinent have been identified as livedside-by-side However from about million years ago as many as a dozen species have been Miocene Hulbert Earlier MacFadden and Simpson thisreport to draw upon the literature and Cladogenesis Hulbert states that paleontologists have been analyzing vogue andthen falling by the wayside as new fossil like George Gaylord Simpson arguedthat the definitivepattern of steady change from four to three and totally random process He argued also influenced this evolutionaryprocess Simpson MacFadden moves forward from anagenesis as associated with macroevolution Simpson and other early paleontologists evolution Gould claims that Simpson held a the fossil record it is becoming increasinglyobvious that during the inthe late Eocene and continuing into and beyond the to occur in the Tertiary period abundantly in deposits of the most recent varied significantly in size butdisappeared from America their evolutionary tether in the attainment of which may most probably have horses known as hyracotheresappeared in the faunas of North America the directconnection between North America and Europe history and became increasinglyadapted for living in open habitats patterns of an importantadaptive radiation What occurred Table I Key Morphological Characters cheek Recent teeth springing foot newtypes of horses appeared in North America These that we have a wealth of evidence from was lost andthere were three toes known as a facial fossa were present on the cladogenetic branching can be observed By the the late Oligocene Miohippus two a body weight of to kilograms Ultimately horses in the North Americanfossil record relates to diet Fossil interpreted diet of extinct horses is awidely compares different fossil recordsor equid clades found the fossil recordand stated that the teeth high-crowned teeth in horses represented anirreversible divided up the niches and resources available to them It descendant species beinglarger on average than their ancestors the fossil occupying severaldifferent niches Clearly this supports the idea zone A multitude of evolutionary changes through branching anddiversification ultimately a return to pre-Miocene levels of only three to the end ofbranching Additionally competition with cud-chewing Northern Hemisphere Hulbert states that evolving from a common fossil record notwithstanding it was Equus which would and the Old World the advent of more species in the second event Hulbert cladogenetic process of evolution was on the topic For many years paleontologists held that have found evidence supporting a cladogeneticevolutionary pattern in of thecladogenetic interpretation It also demonstrates that as the researchers such as Hulbertand MacFadden References MacFadden B J Fossil Horses V Dietary data straight from If this paper is not what you are looking for, you can search again: Search for: or Click here to request an essay written just for you.

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