A species is a group of organisms that can create more offspring by reproducing new fertile individuals. As a result, two organisms that are incapable of reproducing and producing fertile offspring are classified as distinct species. Speciation is the process of creating new species. Allopatric speciation and sympatric speciation are the two main pathways for the development of new species.
The name “allopatric” comes from the Greek terms “allos” and “Patris,” which mean “other” and “fatherland,” respectively. When an organism’s population gets divided or isolated from its main group, allopatric speciation occurs. The word sympatric comes from the prefix sym-, which means “same” or “together,” and patris, which means “fatherland” in Greek. This sort of speciation happens in non-geographically isolated populations.
Speciation
A species is a collection of creatures that have similar features and can reproduce through interbreeding. Speciation, on the other hand, is the process of generating new species from existing ones as a result of external variables like geography.
The newly developed species are reproductively isolated from their predecessors, preventing interbreeding.
Factors Influencing the Speciation Process
Geographical Isolation:
Due to a range of circumstances such as mountain rise, continental drift, organism mate, and so on, a number of species migrate to various locations and are unable to interbreed, resulting in speciation.
Reduced Gene Flow:
There is a chance of reduced gene flow but not absolute isolation when two individuals are unable to mate owing to a number of causes.
Hybridization
Hybridization is a way of producing new species that has been developed by humans. Two parents of different species mate to produce a third species in animal husbandry. The impacts of hybridization on the speciation process are numerous.
Speciation -Benefits
Speciation has a number of advantages, including the following:
- Speciation teaches organisms how to adapt to their surroundings.
- It promotes the abiotic and biotic elements’ ecological equilibrium.
Speciation -Disadvantages
- It is not possible to gather fossil records using this method.
- It is not found in asexual species.
- Only applies to populations that are geographically separated.
Allopatric Speciation
When an organism’s population gets divided or isolated from its main group, allopatric speciation occurs. As a result of pressure from predators, climate, rivals, and resources, natural selection produces changes in the allele frequency in the new group, which was previously homogeneous among individuals, over time.
Populations can become isolated for a variety of causes. Earthquake-induced changes in land topography, seeds scattered by the wind and transported away in rivers, flooding, migration, and erosion are only a few examples. Allopatric speciation can be shown in Darwin’s Finches and squirrel populations in the Grand Canyon. The greater the distance between species, the more likely speciation is, according to studies.
Examples of Allopatric Speciation
Darwin’s Finches
Charles Darwin found a notable case of allopatric speciation in Galapagos finches. On the Galapagos Islands, there are 15 different types of finches, each with its own distinct characteristics such as a beak for eating different sorts of food, however all finches share a common ancestor that arose due to isolation on separate islands. Surviving birds grow common in their surroundings, forming a variety of species. Adaptive evolution is the term for this.
Squirrels of the Grand Canyon
They establish a natural barrier between the squirrels that live in the region when they form. Due to geographical changes, squirrel populations became separated and dispersed in different places, resulting in two unique species.
Sympatric Speciation
They establish a natural barrier between the squirrels that live in the region when they form. Due to geographical changes, squirrel populations became separated and dispersed in different places, resulting in two unique species.
Autopolyploid
In this circumstance, an organism contains two or more sets of chromosomes from the same species. This is what happens in plants during meiosis, when all of the chromosomes are transferred to one of the daughter cells.
When this happens, the gametes produced are incompatible with those of either parent for reproduction. On the other hand, the organism can self-pollinate or reproduce with another creature that has the same number of chromosomal pairs as it.
Allopolyploid
The allopolyploidy kind of sympatric speciation happens when two distinct species mate and generate offspring. The gametes of the first-generation offspring must unite with normal gametes from one of the two original species to produce viable offspring.
The origins of roughly half of all plant species can be traced back to a polyploid species. Tobacco, cotton, and wheat are examples of agricultural plants.
Difference between Allopatric and Sympatric Speciation
|
Parameters |
Allopatric Speciation |
Sympatric Speciation |
|
Need of Geographical Isolation? |
Yes |
No |
|
Mechanism of Differentiation |
Natural Selection |
Polyploidy |
|
New Species Creation |
Slow |
Fast and Slow |
|
Common in Nature |
Yes |
Yes- in Plants |
|
Examples |
Squirrels etc. |
Cultivated corn, wheat etc. |
Conclusion
Physical isolation of a population due to an external barrier is referred to as allopatric speciation. Physical isolation of a population due to an external barrier is referred to as allotropic speciation. Sympatric speciation describes the emergence of new species from a single ancestral species that shares the same habitat. Sympatric speciation can be divided into two categories:
Autopolyploidy: In this circumstance, an organism possesses two or more sets of chromosomes from its own species, and
The allopolyploidy kind of sympatric speciation happens when two distinct species mate and generate offspring.