Difference Between Natural and Artificial Selection

Main Difference – Natural Selection vs Artificial Selection

Natural selection is a nature-made selection, and artificial selection is a man-made selection. The main difference between natural and artificial selection is that natural selection produces a great biological diversity whereas artificial selection produces varieties of organisms such as improved crops and livestock. Artificial selection, which is also called selective breeding, is mainly used in domestic populations. It is mainly used to maintain only beneficial traits over generations. However, natural selection only allows the favorable traits for the environment to be inherited by successive generations.   

Key Areas Covered

1. What is Natural Selection
      – Definition, Features, Role, Examples
2. What is Artificial Selection
      – Definition, Features, Role, Examples
3. What are the Similarities Between Natural Selection and Artificial Selection
      – Outline of Common Features
4. What is the Difference Between Natural and Artificial Selection
      – Comparison of Key Differences

Key Terms: Artificial Selection, Genetic Variation, Mutations, Natural Selection, Population, Speciation, Species, Selective Breeding, Variation

What is Natural Selection

Natural selection is the main process that allows organisms to adapt to their environment for better survival and increase the number of individuals in the population through interbreeding. Natural selection contributes significantly to evolution. Mutations, gene flow, and genetic drift also drive evolution. The grand concept of evolution and natural selection was first fully expounded by Charles Darwin.

Variation, inheritance, high rate of population growth, differential survival and reproduction are the five steps of Darwin’s process of natural selection. In order to select, there should be genetic and phenotypic variations among individuals within a population. The genetic variation among individuals may occur due to mutations, gene flow, and genetic drift. All individuals within the population do not reproduce in their full potential due to limited environmental factors. Thus, differential reproduction is involved in the selection of a set of characters to be inherited by the offspring. As a result, the best-fitted phenotypes to the environment may accumulate in the offspring. In brief, the variation within the population is inherited, and ultimately, a differential reproductive success emerges due to variation. Once individuals within the same population are incapable of interbreeding, population subdivision or speciation occurs. Through speciation, natural selection forces the process of evolution.

Figure 1: Natural Selection

The most well-known evidence of natural selection is the effect of industrial revolution on peppered moths. Two types of peppered moths were found on the tree trunks as light color peppered moths and dark color peppered moths. Before the industrial revolution, light color tree trunks were found in the environment due to the lichen growth. With the industrial revolution, the tree trunks were darkened by soot and other industrial. The lichens were also destroyed by the air pollution. Thus, the light color morph of the peppered moth became less common due to the selective predation of birds. The dark morph became more abundant.

Figure 2: The selection of long-necked giraffes by the environment

The prominence of the long-necked giraffe is another example of natural selection. The long-necked giraffes are capable of better feeding when compared to giraffes with short necks. Therefore, the long-necked giraffes become more prominent in the environment. The selection of long-necked giraffes by the environment is shown in figure 2.

What is Artificial Selection

Artificial selection is the selective breeding of animals and plants to produce an offspring with desirable and inheritable characters. Artificial selection is a man-made selection process of desired characters, and it is mainly used in livestock and improved crops. Farmers used artificial breeding even before Darwin’s discovery genetics to maintain inheritable characters which they desired in both animals and plants. The beneficial characters such as the ability to produce more milk in cattle, the accelerated lean muscle growth, exotic pets such as Savannah cat and small dogs such as Chihuahua are produced by artificial breeding. A Belgian cow is maintained by selective breeding due to its accelerated lean muscle growth.

Figure 3: A Belgian cow

Furthermore, artificial selection is used in the production of untold diversity in plants. Corn, wheat, and soybeans strains are developed by artificial selection of beneficial traits in agriculture. Broccoli, Brussels sprouts, cabbage, cauliflower, collards, and kale are produced by the careful selective breeding of wild mustard. Roses and orchids are also cultivated by selective breeding. Artificial selection can also produce various colors in carrot roots.

Figure 4: Carrots with multiple colored roots

Similarities Between Natural and Artificial Selection

• Both natural selection and artificial selection are two methods involved in the breeding of organisms.
• Both natural selection and artificial selection allow selected characters to pass to the next generation.

Difference Between Natural and Artificial Selection

Definition

Natural Selection: Natural selection is the process whereby organisms better adapted to their environment tend to survive and produce more offspring.

Artificial Selection: Artificial selection refers to the process by which animals and plants are chosen by the breeder to produce desirable and inheritable characters in the successive generations.  

Selection

Natural Selection: Natural selection is a nature-made selection process.

Artificial Selection: Artificial selection is a man-made selection process.

Significance

Natural Selection: Natural selection produces a huge biological diversity.

Artificial Selection: Artificial selection produces organisms with selected traits.

Occurs in

Natural Selection: Natural selection occurs in natural populations.

Artificial Selection: Artificial selection mainly occurs in domestic populations.

Importance

Natural Selection: Natural selection only allows favorable characters to be inherited over the successive generations.

Artificial Selection: Artificial selection allows only selected traits to be inherited over successive generations.

Speed

Natural Selection: Natural selection is a slow process.

Artificial Selection: Artificial selection is a rapid process.

Effect on Evolution

Natural Selection: Natural selection facilitates evolution through generating biological diversity.

Artificial Selection: Artificial selection does not facilitate evolution.

Examples

Natural Selection: The selection of long-necked giraffes, the selection of dark color moths, and the change in the size and the shape of beaks of birds upon the available food are the examples of natural selection.

Artificial Selection: The breeding for small dogs such as Chihuahua, Boston Terrier, and cattle which can produce more milk are examples of artificial breeding.

Conclusion

Natural selection and artificial selection are two methods involved in the breeding of organisms. Natural selection is governed by the selective pressure of the environment. Artificial selection is governed by the breeder. Natural selection produces a great biological diversity on earth. In contrast, artificial selection facilitates the inheritance of desired characters by the breeder. Therefore, the main difference between natural selection and artificial selection is the selective force of each method and the types of characters inherited by the offspring in each method.

Reference:

1.”Natural selection.” Understanding Evolution. N.p., n.d. Web. Available here. 31 July 2017. 
2. Selective Breeding or Artificial Selection. N.p., n.d. Web. Available here.  31 July 2017. 
3. “Life Science: Session 5 Artificial Selection at Work.” Annenberg Learner. N.p., n.d. Web. Available here. 31 July 2017. 

Image Courtesy:

1.”Mutation and selection diagram” By Elembis – GPL image Image:643px-Explanation of Evolution v2.1.PNG (CC BY-SA 3.0) via Commons Wikimedia
2. “Selection” By I Toony (CC BY-SA 3.0) via Commons Wikimedia 
3. “Sectio caesarea” By The original uploader was Barbarossa at Dutch Wikipedia – Transferred from nl.wikipedia to Commons. (CC BY-SA 3.0) via Commons Wikimedia
4.”Carrots of many colors” By Stephen Ausmus – This image was released by the Agricultural Research Service, the research agency of the United States Department of Agriculture, with the ID K11611-1 (Public Domain) via Commons Wikimedia