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Speciation

From CreationWiki, the encyclopedia of creation science

Speciation is an important theoretical framework to explain the formation of new species and is one of the major themes of evolutionary and creation biology. Speciation can be defined as the point in time when members of a population become separated so much so that in certain cases no mating or gene flow between the two groups exists. This most often occurs as a result of crossing geographic barriers, such as rivers or mountain ranges. Simply being separated by miles of land can lead to such dramatic and irreversible differences between related plants and animals that we can, at times become unable to recognize them as belonging to the same created kind.

This occurs because the Earth is a ecologically diverse place, and an organism can find itself in an altogether different biome after simply crossing over a mountain. Through time ecological niche's are then created completely different from the originally related species. While living in separate ecological zones, two related populations will experience unique, permanent by either behavioral or genetic causations, natural selection pressures, and they will adapt behaviorally and morphologically to different habitats. Existing as a separate species is potentially transient in nature since the geographic barrier may be overcome in time.

1 Modes of Speciation
2 References
3 External Links
4 See Also

Modes of Speciation

Allopatric

Allopatric speciation involves heavy geographical seperation and thus encourages seperate specie formation from the original parent population. Following a significant period of separation, the isolated species differentiation can become truly permanent at the genetic level. It is through a history of genetic recombination and natural selection that make the genome affected to an extent where the chromosomes can become unable to pair and crossover during the first mitotic division following fertilization. This can literally make the specie no longer able to reproduce with the original parent population even in captive situations. ^[1]

Peripatric

Hypothetically let us say that there is a type of highly social bird, male and female that were taken onto a boat. Even though they survived this long journey they were displaced thousands of miles and introduced into a completely different ecosystem. These new environmental influences on this tropical island forces these birds to adapt and survive or face death. In spite of the circumstances the species thrive and produce offspring as time passes until a small population has been accumulated.

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 virture of their distinctive call. The preference resulted in rapid speciation between the two populations of southern frogs.^[2]

During sexual reproduction genes that may not of been activated before now have to be as they were chosen as being best to allow survival. The activated genes may produce changes in behaviorial choices of mates for instance. These new genes eventually become solidified within the population of these birds after many more generations pass. Enough differences begin to develop within the shared genetic makeup and the new phenotype expression dominates succesive generations so much so that it can no longer be considered consistent with the parent population as it once was.

Peripatric speciation can only be called so when there is geographic isolation with small populations, seperated from the parent or ancestory population. ^[3]

Sympatric

The divergence of multiple populations from a single parent species yet they still inhabit the same geographic region. 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. ^[4]

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. The instinct to remain separate and intricate natural processes that enable this difference indicates the existence of intelligent design behind the development of new species. It is obvious that the retention of a specific adaptation is reliant upon the organisms remaining separate in a geographical way. Finely tuned specializations develop over a great many generations, which would be immediatly lost upon cross-breeding with a related population but conversely would make the organism genetically isolated from the original parent species.