Speciation

Speciation is the natural process by which new species are formed. A species is generally defined as a naturally-occurring population that is actually or potentially interbreeding and reproductively isolated from other such groups (Ernst Mayr 1942). The formation of a new species most often occurs when members of an established population become separated, preventing mating or genetic flow between the groups. Organisms that were once capable of interbreeding will gradually develop barriers to reproduction when segregated and exposed to differential selective pressures. This process results in two or more genetically distinct groups of organisms that are no longer capable of interbreeding (species).

Speciation is the leading mechanism responsible for the diversification of the created kinds of plants and animals into many physically distinct groups (see: biological evolution). The formation of new species has been a frequent part of biological history largely due to the ecological diversity of the Earth. Organisms can encounter dramatically different biomes after only a short migration, to which they must adapt. The genetic changes that accomplish these adaptations can render related groups genetically incompatible so that fertilization is no longer possible.

The identification of speciation is problematic since it is reliant upon the determination of reproducibility in nature. Separate species names have been assigned to groups that were later discovered to interbreed, though do so infrequently. Others have been established as capable of mating in captivity, and yet no evidence of natural reproduction is known. Despite these difficulties, speciation is an important theoretical framework for understanding the history of life on Earth, and one of the major themes of evolutionary and creation biology.

Creationist History

Early creationists assumed that species were fixed and unchanging, and held to be synonymous with the created kinds referred to in the Bible as illustrated in The Genesis Record (1976) when Henry Morris states:

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It will probably be found eventually that the min [Hebrew word for kind] often is identical to the "species," sometimes the "genus," and possibly once in a while with the "family".

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However, due to improved understanding of speciation, it is now widely recognized by creationists that the process can occur rapidly and has been a regular part of the development of the Biblical kinds. In contrast to these earlier views, today most creation scientists see the reverse; equating the "family" level as most often identical to the kinds of the Bible, sometimes the "genus," and only possibly once in a while with the "species".

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The biblical creation/Fall/Flood/migration model would also predict rapid formation of new varieties and even species. This is because all the modern varieties of land vertebrates must have descended from comparatively few animals that disembarked from the ark only around 4,500 years ago. In contrast, Darwin thought that this process would normally take eons. It turns out that the very evidence claimed by evolutionists to support their theory supports the biblical model.

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Since simply crossing geographic barriers provides sufficient separation to initiate speciation and can lead to dramatic and irreversible changes, this process has led to great difficulty in accurately identifying the created kinds. This is perhaps one of the biggest challenges for creation biologists, and the practice of a growing field of creation science called baraminology. One important tool used by baraminologists is hybridization data, since a successful mating between two different species would confirm they are close relatives.

Modes

There are three different modes of speciation that delineate between heavy and small geographic isolation and the sizes of the populations of the organisms being studied. The isolating mechanisms are either genetic or behavioral. The degree of geographical isolation correlates with the amount of environmental pressure on the population.

Allopatric

Allopatric speciation occurs when there is extreme geographical isolation between child and parent species. After a significant period of separation that allows the communities of the child species to begin to flourish, mutations and epigenetic changes occur. The organisms are no longer able to sexually reproduce with the original parent species. If the process of speciation changes the number of chromosomes in either of the species, hybrids between the two species may be embryo lethal or infertile. This makes the species no longer able to reproduce with each other even in captivity.

When isolated populations (north, south) of the green-eyed tree frog met again, each had changed in subtle ways. The calls of the male frogs were different, and more importantly, the offspring of a north-south pairing didn't survive well. One population that was cut off from its southern kin (isolated south) found a way to ensure healthy young. Isolated southern females selected southern males by virtue of their distinctive call. The preference resulted in rapid speciation between the two populations of southern frogs.

Peripatric

Genes that may not have been activated before are activated to allow survival within a small child population separated from the parent population. The activated genes may produce changes in mate selection. These new genes eventually become solidified within the population because they enable the flourishing of the species. After many more generations, there may be enough genetic difference within the small isolated child population that it constitutes its own species. Peripatric speciation differs from allopatric speciation because it defines itself by two parameters, namely geographic isolation and small populations.

Sympatric

One of the most rarest of the geographic modes of speciation is sympatric divergence of multiple populations from a single parent species that still inhabit the same geographic region. It is more focused on gene flow rather then geographic barriers to divergence. Many develop ritualistic behaviors or unique features that allow them to preferentially choose mates if they still possess the ability to produce fertile offspring, and can be coaxed to do so in captive situations.

Parapatric

This particular speciation is brought on through mating frequency of a population loosely tied with geographical location. This is limited as the organisms find ecological niches, thus easing the need for mutation and selection change of genes. Finely tuned specializations develop over a great many generations, which would be immediately lost upon cross-breeding with a related population but conversely would make the organism genetically isolated from the original parent species.

Number of species

Speciation has produced a wide variety and number of species that scientists have been trying to count and classify for at least 200 years. Some estimate there may be as many as 30 million species today, a number touted by evolutionists as evidence against the biblical history of the global flood. Some argue that if there are so many species today, then through extrapolation into the past, the ark of Noah could not of possibly held so many species, allowing re-population of Earth as the Bible states. Following the evolutionists logic if the known number of species that populate Earth today decreases, then the credibility increases as well as the probability of the Ark housing all necessary representative species. The number 30 million was arrived at by Terry Erwin of the Smithsonian Institute in Washington DC during the early 1980's, concluded in part by counting the amount of beetles living in the canopy of a single tree in Panama. The number relative to beetles on that single tree in Panama was then extrapolated with various assumptions underlying it attempting to prove grander hypotheses to include all of the worlds species. The assumptions however tainted the extrapolation methodology producing a number that was to high according to recent findings in 2010, but also at the same time the number reached by Erwin was to low showing inconsistent application of his own methodology. The number should of been much higher, around 100 million if Erwin's initial numbers were correct. The revised figures posited in 2010 by Andrew Hamilton at the University of Melbourne, Australia shows that the amount of species populating Earth today is now considered, by most scientists, as a much lower number estimated around 8 million.

Number of Kinds vs Species

See also: Specialization (Genotype)

The creationist model presumes that the Creator specifically created individual kinds of animals, each with the ability to "hyper-adapt". That is, the original male/female pair's DNA contained all the representative traits that their offspring would ever exhibit (a master genome). As "kinds" are more representative of the "family" rather than species, the Ark would not have to carry so many of them. Considering that the average land animal is the size of a common sheep or smaller, and the Ark's capacity was equivalent to 550 standard boxcars, we may reasonably assume the Ark was large enough to carry pairs from all the families of animals.

Once they exited the Ark and God commanded them to be fruitful and multiply, the hyper-adaptive capabilities of their genomes allowed them to spread out and rapidly diversify, specializing into their various habitats as their populations grew, and they split populations to find food or avoid crowding.

The hyper-adaptivity is an important distinction from hyper-evolution, which secularists claim would be necessary to reach today's biodiversity in less than 4000 years. In hyper-evolution, the evolutionary processes (gain-of-function and gain-of-genetic-material which purportedly require very long time frames), would not have reached today's biodiversity in 4000 years. A hyper-adaptive model however, could easily account for today's biodiversity because no new genetic material is necessary. The genomes are essentially "front-loaded" with the necessary adaptive characteristics to be successful in many diverse habitats. In fact, the specialization-and-adaptation activity, coupled with mutations, actually cause the appearance of speciation which secularists mis-interpret and mis-apply.

Evolutionary potential

With cases of speciation the conclusion is clear if following observational science. Speciation will not produce radical biological structure dissimilarity resulting in a different animal, such is needed to support molecules-to-man evolution, but rather deeply unique and wide-ranging phenotype diversity of structures that constitute specific kinds of animals.

Beyond phenotype expression, any other conclusion will not suffice but rely on extrapolation that assumes deep time.

External Links

Creation

• Get Answers: Speciation by Answers in Genesis

Secular

• Allopatric Speciation Tested in Martinique By Darwin's God blog
• How Many species are there, really? 24 May 2011
• Speciation: more likely through a genetic or through a learned habitat preference? J.B Beltman and J.A.J Metz Proc Biol Sci. 2005 July 22; 272(1571): 1455–1463. Published online 2005 June 28.
• Complex speciation of humans and chimpanzees Uncommon Descent. Mario A. Lopez.
• Integration of populations and differentiation of species by Loren H. Rieseberg, Sheri A. Church, and Carrie L. Morjan
• Sympatric speciation under incompatibility selection by Yael Artzy-Randrup* and Alexey S. Kondrashov
• Isolation-by-Distance and Outbreeding Depression Are Sufficient to Drive Parapatric Speciation in the Absence of Environmental Influences by Guy A. Hoelzer, Rich Drewes, Jeffrey Meier, and René Doursat
• Introduction. Speciation in plants and animals: pattern and process by Richard J Abbott, Michael G Ritchie, and Peter M Hollingsworth
• The speed of ecological speciation by Andrew P. Hendry, Patrik Nosil, and Loren H. Riesberg
• Plant Speciation by Loren H. Rieseberg, and John H. Willis