Species And Biodiversity Crises: Testing The Link In The Late Devonian Period

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There are few transformations more astonishing than that of Earth. This planet underwent a dramatic metamorphosis from a relatively barren amalgamation of chemicals to a vibrant and dynamic place teeming with flora and fauna. The inexplicable intricacies of our varied ecosystems have intrigued many throughout the course of history, scientists and laypeople alike. By studying the history of the ever-changing environment, not only do we gain a better understanding of our past and the world around us, but also a means by which to distinguish patterns of change and predict our future conditions. One such scientific field of study that allows us a glimpse into the past is evolutionary biology. Studying evolutionary behavior is of utmost importance, …show more content…

Stigall (2010) approaches the study with knowledge that the massive loss of biodiversity of the late Devonian Period is likely due to a lack of speciation. Stigall (2010) attempts to single out which mode of speciation, or lack thereof, most affected the marine ecosystem, as well as what caused this decrease in speciation. The study focuses on the two most common means of speciation - vicariance and dispersal. Speciation by vicariance refers to when a certain clade is divided into two subspecies which later evolve into separate daughter species while speciation by dispersal happens once a small group of a species reallocates and forms a new species. Stigall (2010) predicts that the decrease in speciation by vicariance is primarily responsible for the biodiversity crisis of the Late Devonian period. The phylogenetic data for the marine invertebrate clades Schizophoria, Floweria, and Leiopteria is analyzed via the standard steps of the scientific method to research the cause of mass extinction and biodiversity loss in the late Devonian period. Ultimately, what is shown is that there is a dramatic lack of speciation by vicariance. In other periods, this type of speciation makes up the majority, while during