Challenges To The Traditional Theory Of The Great American Interchange Research Paper

Length: 5 pages Sources: 6 Subject: Literature - Latin-American Type: Research Paper Paper: #9038866 Related Topics: Primate, South American, Ecology, North American

Excerpt from Research Paper :

Evolution -- Great American Interchange

The natural Panamanian bridge adjoining early North America with early South America is believed to have occurred 3 -- 4 million years ago. By studying evolutionary changes in animal species in North America, Central America and South America, experts formed the theory of the Great American Interchange, a mutual migration of Northern species to South America and of Southern species to North America. The evolutionary changes that came from these migrations are at least partially attributed to a Great American Biotic exchange. Experts traditionally believe that Northern species that migrated to South America were more successful in surviving and evolving because of prior migrations from greater land masses and easier adaptation to the climate of South America. However, as experts make more and more discoveries in the field, there are questions and controversies about the number of migrations from each continent and migrations from sources other than the Panamanian bridge. The raised questions and controversies seem to expand our knowledge about the evolutionary events in pre-History.

2. Body: How the Great American Interchange Affected Animal Evolution

a. Important Results from recent primary literature articles and how they shape our current understanding of the topic

The Great American Interchange was the migration of North American (Nearctic) species to South America and South American (Neotropic) species to North America due to the rise of the natural Panama land bridge between North America and South America 3 -- 4 million years ago during the Pleistocene Period (Smith and Klicka 334). The Great American Interchange resulted in a Great American Biotic Interchange, resulted in the evolutionary diversity of several species, both the North and South Americas, with different origins and different evolutionary paths (Jimenez, Gardner and Navone 1167). The Nearctic species that migrated to South America were more successful in evolving and surviving than were the Neotropic species, as evidenced by fossil finds in North America, Central America and South America (MacFadden 162). Some experts maintain that approximately 17 New World species evolved, 12 of which remain (Jimenez, Gardner and Navone 1168). The 5 New World species who suffered extinction did so because of competition for survival sources,...


This traditional theory supports a far neater scenario than the possible explanations, questions and challenges created by new discoveries.

b. Controversies in the Field (what is the evidence for and against various theories?)

There are several controversies in the field regarding the effects of the Great American Interchange on the evolution of animals. The controversies appear to involve the question of multiple migrations only from North to South, multiple migrations from both directions, additional migrations from other avenues such as water, and ultimately the reasons for the Northern or Nearctic species' apparently greater success after migrating to South America.

The prevailing traditional belief is that the migrations North and South were basically even, according to an equilibrium theory (Jablonski and Sepkoski 1367), and that Northern animals succeeded in their new Southern geographic area better than Southern animals succeeded in their new Northern geographic area for 2 reasons: because they were used to more vigorous evolutionary competition over a larger land mass from prior Eurasian migrations; and because they were better able to adjust to the South American climate (Jablonski and Sepkoski 1367). However, other experts believe that the greater survival rate of Nearctic animals in South America was due to a greater number of migrations from North to South (Perini, Russo and Schrago 657), rather than to genetic superiority or outright size. This belief in several Northern-to-Southern migrations at different times is supported by the discovery of 2 new fossils of procyonids in Venezuela, outside and north of Argentina, which are similar to Procyonid fossils found in the southern part of South America (Forasiepi, Soibelzon and Suarez Gomez). If the theory that there were multiply more Northern-Southern migrations than Southern-Northern migrations is true, the sheer number of migrating Northern animals may at least partially account for their evident success in South America.

The traditional equilibrium migration theory is also challenged by other experts who are that there is evidence of several migrations from South America to North America, concluded from tracing the movements of parasites in and around animal fossils from South to North (Jimenez, Gardner and Navone 1170). Other experts who agree with the multi-migration theory believe that diversity in phylogenetics of these species is traceable to…

Sources Used in Documents:


Davies, T Jonathan and Lauren B. Buckley. "Phylogenetic Diversity as a Window into the Evolutionary and Biogeographic Histories of Present-Day Richness Gradients for Mammals." Phiosophical Transactions of the Royal Society B: Biological Sciences, 366(1576) (August 2011): 2414-2425. Print.

Forasiepi, Analia M, et al. "Carnivorans at the Great American Biotic Interchange: New Discoveries from the Northern Neotropics." 17 July 2014. Web site. Web. 18 October 2014.

Jablonski, David and j John, Jr. Sepkoski. "Paleobiology, Community Ecology, and Scales of Ecological Pattern." Ecology, 77(5) (July 1996): 1367. Print.

Jimenez, F Agustin, et al. "Four Events of Host Switching in Aspidoderidae (Nematoda) Involve Convergent Lineages of Mammals." Journal of Parasitology, 98(6) (Dec 2012): 1166-75. Print.

Cite this Document:

"Challenges To The Traditional Theory Of The Great American Interchange" (2014, October 21) Retrieved April 1, 2023, from

"Challenges To The Traditional Theory Of The Great American Interchange" 21 October 2014. Web.1 April. 2023. <>

"Challenges To The Traditional Theory Of The Great American Interchange", 21 October 2014, Accessed.1 April. 2023,

Related Documents
Challenge of Managing All Stakeholders in the Context of a Merger...
Words: 23212 Length: 80 Pages Topic: Business Paper #: 46964051

Managing All Stakeholders in the Context of a Merger Process Review of the Relevant Literature Types of Mergers Identifying All Stakeholders in a Given Business Strategic Market Factors Driving Merger Activity Selection Process for Merger Candidates Summary, Conclusion, and Recommendations The Challenge of Managing All Stakeholders in the Context of a Merger Process Mergers and acquisitions became central features of organizational life in the last part of the 20th century, particularly as organizations seek to establish and

System Theory the Origin and
Words: 4711 Length: 17 Pages Topic: Black Studies - Philosophy Paper #: 99908857

However, in the most recent theory of evolution which discusses the living world appears as the result of chance and an output of different randomly selected natural mills. This kind of development came to present as a result of the need of more subjects or topics in areas such as cybernetic, general system theory, information theory, theories of games which is needed in most decision making process in line

ERP Systems Challenges of Enterprise
Words: 22297 Length: 81 Pages Topic: Business - Management Paper #: 27293594

Role-based ERP systems are critical for the siloed, highly inefficient architectures of legacy ERP systems to be made more relevant, contribute greater financial performance, and lead to higher levels of overall customer satisfaction. c. Purpose of the study The purpose the study is evaluate how enterprises who adopt role-based ERP system implementations are able to attain higher levels of financial and operations-based performance vs. those that rely on silo-based, more functionally

Application Social Work Leadership Theories
Words: 2748 Length: 8 Pages Topic: Terrorism Paper #: 67228914

Social Work Leadership Theories and Areas of Application Leadership Theories - Servant The philosophy and collection of practices constituting the 'servant leadership' style enrich people's lives, improve organizations and, eventually, foster a kinder and fairer world. While the concept is ageless, the coining of the term "servant leadership" is attributed to Robert K. Greenleaf, who cites it in his 1970 essay, The Servant as Leader. In his paper, Greenleaf states that servant-leaders

Fidelity Investments Human Resources
Words: 3039 Length: 10 Pages Topic: Business Paper #: 19202715

Fidelity Investments- Human Resources Fidelity Investments Fidelity Investments- T&D Program HR Transformation strategy- Fidelity Investments Key Issues identified in interview Communication Change management Technology utilization Business Case: Context of program application Mission Metric Financial Metric Operational Metric HR redesign Accountability Table 1- Implementation and Accountability of L&D program Figure 2 Business Case Rationale for T&D program at Fidelity Figure 3- HR Redesign Elements This HR Learning and Development (L&D) program proposed for Fidelity Investments is aimed at addressing the key challenges faced by the firms in its

E-Commerce Communications
Words: 6773 Length: 20 Pages Topic: Business Paper #: 69057102

E-Commerce Communications Electronic commerce or e-commerce is the term used to describe all forms of information exchange and business transactions based on information and communication technologies. There are different types of formal definitions of e-commerce, but the wide scope involved has resulted in many definitions focusing on only certain aspects. A fairly comprehensive definition covers e-commerce from four different perspectives (Kalakota and Whinston, 1997, p.38) - communications, business process, service and