Can Artificial Selection Create New Species According to Darwinian Theory?

According to Darwinian theory, the natural process of speciation occurs over long periods, often involving hundreds or thousands of generations. However, the ability to artificially create new species has been demonstrated through careful breeding and genetic manipulation. This article explores the concept of artificial selection, its historical context, and the implications for the Darwinian theory of evolution.

Introduction to Artificial Selection

Artificial selection, the process of selecting organisms for reproduction with desired traits, is a well-documented practice dating back thousands of years. Farmers and other humans have been selectively breeding plants and animals to enhance desirable traits, leading to the development of numerous breeds of dogs, cats, and many other domesticated species. This practice has been ongoing for millennia, with wolves evolving into the diverse breeds of modern dogs, for example, or horses.

Artificial Selection in Microscopic Organisms

While artificial selection is often discussed in the context of macroscopic organisms, it has also been observed in microscopic entities such as viruses. Although viruses are technically not considered alive by many biologists, they can undergo genetic changes and selection pressures, leading to the emergence of new strains or types.

Speciation and Artificial Selection

Speciation, the process by which new species are created, typically occurs over extended periods and involves significant changes in the gene pool of a population. While we may not witness speciation in mammals over a human lifetime, we can observe it in more rapidly evolving organisms. For instance, the many breeds of dogs, all believed to have originated from a common ancestor approximately 2,000 to 3,000 years ago, are a testament to the power of artificial selection.

The breeds of dogs today, such as chihuahuas and Great Danes, are often not interfertile, indicating the emergence of new species or at least new breeding populations. This phenomenon has also been observed in other animals, such as coyotes and wolves, which can produce offspring but may be reproductively isolated from their counterparts.

Examples of New Species Created Through Artificial Selection

One striking example of artificial selection leading to new species is the creation of bananas. Bananas are the result of genetic manipulation, where a diploid plant (subspecies Musa acuminata) and a tetraploid plant (subspecies Musa balabacensis) were bred to produce a triploid karyotype. This process created a new species of banana that cannot produce viable seeds, resulting in seedless bananas.

The genus Triticale is another example of a new species created through artificial selection. Triticale is a hybrid of rye and wheat, with a new genus containing four different species, showcasing the ability to create new species through careful breeding.

Hybrid chickens, such as those produced commercially, are also new species in their own right. These chickens have been bred for specific traits and are no longer interfertile with their ancestral breeds, effectively creating new species through artificial means.

Challenges and Limitations

While artificial selection can drive the creation of new species, it is important to note that this process is distinct from the natural selection described by Darwinian theory. Artificial selection involves intelligent intervention, whereas Darwinian evolution is a blind process driven by natural selection pressures.

The theory of evolution demands new species to arise through natural processes, not artificial means. In artificial selection, the selection criteria are set by humans based on desired traits, whereas natural selection is driven by environmental pressures and evolutionary fitness.

Conclusion

While artificial selection has the potential to create new species, it operates under different principles than natural selection. The historical practice of artificial selection, from the selective breeding of domesticated animals to the creation of new plant varieties, demonstrates the power of human intervention in shaping the genetic landscape. However, the validity and implications of this practice remain a subject of debate within the scientific community.