Geographical isolation is a driving force of speciation, hypothesized by Charles Darwin in The Origin of Species by means of natural selection. The emergence of new species is “chiefly grounded on the laws of geographical distribution, that forms now perfectly distinct [species] have descended from a single parent-form,” Darwin argued.
The University of California Berkeley (UCB) Evolution 101 hosts the website page “Causes of Speciation.” Their argument for the theory is logical:
“Scientists think that geographic isolation is a common way for the process of speciation to begin: rivers change course, mountains rise, continents drift, organisms migrate, and what was once a continuous population is divided into two or more smaller populations.”
In testing the theory, Daniel Rabosky of the University of Michigan, and Daniel Matute, of the University of Chicago found the geographical isolation theory of speciation wanting, intensifying the Darwin Dilemma.
Field Study
“Macroevolutionary speciation rates are decoupled from the evolution of intrinsic reproductive isolation in Drosophila [fruit fly] and birds,” by Rabosky and Matute published in the Proceedings of the National Academy of Sciences, found –
“No evidence that the propensity of organisms to evolve reproductive [geographical] isolation predicts the rate at which they form new species over geological timescales.”
In an interview with the University of Michigan, Rabosky explained that –
“Most research on the formation of species has assumed that these types of reproductive barriers [geographical isolation] are a major cause of speciation. But our results provide no support for this, and our study is actually the first direct test of how these barriers affect the rate at which species form.”
According to Rabosky and Matute, if genetic barriers to reproduction are a leading cause of new species, then groups of organisms that quickly accumulate those genes should also show high rates of species formation.
Geographical Isolation Computer Model
This theory was tested by comparing speciation rates to genetic indicators of reproductive isolation in birds and fruit flies. Fruit flies and birds were selected for the study since extensive data sets on experimental interspecies breeding exist for both groups. The researchers used evolutionary tree-based estimates of speciation rates for nine major fruit fly groups and two-thirds of known bird species.
Using computer models to perform a comparison, the results came as a surprise. Rabosky explains –
“We found no evidence that these things are related. The rate at which reproductive genetic barriers arise does not predict the rate at which new species form in nature,”
“If these results are true more generally—which we would not yet claim but do suspect,” Rabosky continued to explain –
“it would imply that our understanding of species formation is extremely incomplete because we’ve spent so long studying the wrong things, due to this erroneous assumption that the main cause of species formation is the formation of barriers [geographical isolation] to reproduction.”
“The whole enterprise of finding ‘speciation genes’ is potentially irrelevant to understanding the origin of species,” Rabosky concluded..
Darwin’s geographical isolation hypothesis, later supported by Evolution 101, that “… isolation are necessary elements for the formation of new species” is not supported by scientific evidence.
Darwin’s Faux Pas
The list of faux pas goes on. Others include pangenesis, spontaneous generation, blended inheritance, sexual selection, uniformitarianism, etc. Darwin’s theory exists only as a philosophy, not as a scientific fact.
More scientifically invalid theories, sadly, have once been advocated by UCB. For years, the site included genetic mutations as a cause of speciation. Replacement theories over the past 50 years have not faired any better. Neo-Darwinism and the Modern Synthesis are dead.
Over the last 150 years since the publication of The Origin of Species, the evolution industry has evolved as master hoodwinking specialists starting into full gear with the Piltdown Man fiasco.
During the past century, advances in technology have radically improved the range and accuracy of scientific inquiry.
As Alan Love of the University of Minnesota concluded in the watershed book entitled Evolution the Extended Synthesis,
“A fully unified view of evolutionary processes may be out of reach.”
Geographical isolation exists only as a philosophy.
Genesis
Despite a flood of challenges since the publication of The Origin of Species, the scientific evidence remains compatible with the Genesis account written by Moses.
Lord Rayleigh, an English physicist and President of the Royal Society, noted during the Scientific Revolution –
“I have never thought the materialist view possible, and I look to a power beyond what we see.”
Evidence from the fields of extinction and speciation to validate the theory of evolution scientifically still remains speculative.
Click to study further evolutionary perspectives on extinction and speciation and other crucial Evolution and Science categories.
Darwin Then and Now is an educational resource on the intersection of evolution and science and the challenges facing the theory of evolution.
Links
- Glossary defines terms associated with explaining the theory of biological evolution.
- Understanding Evolution is a journey that showcases how different investigative approaches play a pivotal role in enriching our understanding of the process, leading to diverse conclusions.
- Studying Evolution delves into the terms species and natural selection and how they have changed since The Origin of Species was published in 1859.
- What is Science investigates Charles Darwin’s approach to science and how the principles of modern science are used for different investigative purposes.
- The Evolution and Science category features articles studying how the intersection of evolution and science influences the current understanding of evolution.
- The Theory and Consensus category features articles examining how scientific findings are influencing the scientific consensus on the essential tenets of evolution, including Natural Selection.
