THE 4 MOST IMPORTANT TYPES OF SPECIATION (WITH EXAMPLES) - BIOLOGY - 2025

The main types of speciation are allopatric, parapratic, stasipatric, and sympathetic. Speciation is the process in which new species emerge from existing ones.

The most common criterion used to speak of speciation is spatial or geographical. The appearance of genetic differences between incipient species is the key element in speciation.

Fruit fly (Rhagoletis pomonella)

It is that the two groups of separate organisms come to have differences that prevent or significantly hinder mating between them.

These differences can be as subtle as the disparity in the mating cycle, for example, and can be caused by natural selection or genetic drift.

What are the types of speciation?

Until now, the following four types of speciation are discussed:

1- Allopatric speciation

It is also called geographical speciation, because it consists of the geographical separation of a group of living organisms so that two or more isolated populations result that do not mate with each other regularly.

This separation usually occurs for natural reasons such as migration, the extinction of geographically intermediate populations, or geological events. In other words, a geographical barrier arises between the original group and the new one that separates them.

This type of speciation occurs even when the "barrier" that hinders mating is violated by a few individuals from any of the groups.

This means that, even if there is gene flow between the two groups, if not on a considerable scale, there is an allopatric speciation.

Example

The finches of the Galapagos Islands are often cited as an example of this type of speciation. On these islands there are different species of finches with a common continental ancestor.

Geographic or allopatric speciation can be divided into three types:

- Geographic or vicarious speciation

It is the classic allopatric speciation in which an ancestral species is separated into two large groups that remain isolated until evolutionary independence appears, thanks to the changes that occur to facilitate or allow local adaptation and geographical differentiation.

For example, the emergence of the Isthmus of Panama was responsible for the speciation of the Alpheus genus of lobsters, which are located on each side of the isthmus.

- Speciation by peripheral populations or peripatric speciation

In this case, the new species emerges from the geographic margins of the territory in which the largest central population is found.

This is the case of a speciation that occurs after a process of dispersion and / or colonization, where adaptation to the new environment generates differences but, since they are small groups, stochastic factors have the greatest weight in these changes.

An example of this mode of speciation is reflected in the drosophila species in Hawaii, which are very numerous due to migration and diversification.

- Speciation in asexual organisms

It is the case in which history determines the identity of the species, and genetic drift becomes a very important evolutionary factor.

2- Parapatric speciation

In this mode of speciation, differentiation occurs even when there is not a complete geographical separation of the groups.

In this case, although the original population is close, the mating is not random due to some subtle variation in the characteristics of some of its members.

Example

To better understand this mode of speciation, the example of some grasses that have grown near a mine is considered.

Those closest to the mine have developed tolerance to heavy metals, while their neighbors have not. This has resulted in their flowering times being different and, therefore, they cannot mate.

It is difficult to differentiate this speciation from allopatric, so many question its presence within the classification.

3- Stasipatric speciation

This type of speciation has been considered by many as a post-colonization speciation, in which evolutionary independence appears by chromosomal mutations.

In this speciation, a chromosomal mutation allows a group to colonize more easily.

Such mutations are fixed in the small groups with little migration and a new species emerges, very similar to the original and that, in fact, will occupy the same range of distribution.

Example

The Australian grasshoppers of the genus Vandiemenella are a clear example of this speciation, given the stability of their distribution over the years.

4- Sympatric speciation

This type of speciation does not imply a large-scale geographic separation between populations, but it does imply that one of the groups uses a different ecological niche within the range of the original species. Thus, reproductive isolation arises.

Example

An example of speciation is the apple fly. In these species, gene flow has diminished, although they live in the same geographic region.

Another type of sympatric speciation involves the formation of an asexual species from a sexual precursor species. This type of speciation has a variant that occurs due to specialization, normally due to adaptation to a resource.

An example of this case is that of the fruit fly (Rhagoletis pomonella) that mates on the fruits of some plant species, in this case called hosts, but whose larvae develop inside the fruit.

Several species within this genus of fly have changed hosts.

This speciation appears to be common among parasitic species and in lake aquatic organisms, such as cichlid fish in African lakes.

These speciation processes are the answer to the questions posed by evolutionary biology.

References

1. Biology Blog (2017). «Species and speciation» in Biology Blog. Recovered from Biology Blog: blogdebiologia.com
2. Cuevas, E. (2013). "Mechanisms of ecological speciation in plants and animals" in Biological. Recovered from Biologics: biologicas.umich.mx
3. Perfectti, Francisco (s / f). "Speciation: modes and mechanisms" at the University of La Rioja. Recovered from the University of La Rioja: dialnet.unirioja.es
4. Spanish Society of Evolutionary Biology (s / f). "Modes of speciation" in the Spanish Society of Evolutionary Biology. Recovered from the Spanish Society of Evolutionary Biology: sesbe.org
5. Spanish Society of Evolutionary Biology (s / f). "Speciation modes" at Berkeley University of California. Retrieved from Berkeley University of California: evolution.berkeley.edu
6. wikipedia.org