Table of Contents
What is Natural selection?
- Natural selection is the process that allows an organism to adapt to changing environmental conditions through the introduction of changes in the genotype of its genetic material.
- Natural selection is among the four major mechanisms that drive evolution, alongside genetic drift, mutation and migration.
- Charles Darwin popularized the concept of natural selection in his research on evolution.
- According to Darwin Natural selection is not a deliberate mechanism and is caused by changes in the environmental and the genetics of organisms.
- Based on the principle in natural selection modifications in the genetics of an organism that improve the chance of an organism to reproduce and survive are maintained and passed on to the next generation.
- Changes that are less beneficial but they will be eliminated as the number of generations increase.
- Natural selection results in the formation of new niches, which could eventually leading to speciation. Therefore, natural selection is a fundamental process of evolution.
- Natural selection may be due to variations in fertility, survival and mating success in other areas that are part of the human lifecycle.
- Whatever the size of these changes are, so long as they’re heritable, they could cause a natural change across many generations.
- In this manner nature selects organisms with certain traits that are beneficial to them, which result in reproductive advantages, leading to evolutionary changes.
- The notion of fitness is vital when talking about natural selection. The fitness of an animal isn’t solely determined by how long it can live however, it is also determined by the success of its reproduction.
- In other words, if an animal is only half the time as other animals, yet is twice as likely to have offspring who live to adulthood, that animal is thought to be more healthy and, consequently, is “selected” by nature.
- Another way to ensure natural selection is through competition in which the most fit individuals are able to compete with those less fit individuals for shelter, food and other necessities.
- Due to this contests, the less healthy individuals are killed and the fitter ones to live and reproduce.
- Natural selection is, however, an ongoing process that can take several generations to allow the results to be evident.
- It is a natural population, which results in a huge biodiversity that may be random.
- The increased diversity results in the increase of heterozygous genotypes in the species.
- Natural selection is a variety of examples. include the choice of long-necked giraffes , as well as the alteration in the shape and size of the beaks of birds in relation to their eating habits.
Examples of natural selection
Selection of long-necked giraffes
The choice of giraffes with long necks from short-necked giraffes is an excellent example that natural selection. It is believed that years ago, both short-necked and long-necked Giraffes lived on the planet. As time passed the food available on the land began to become very scarce. So, the giraffes had to eat leaves on tops of tall trees. The giraffes with long necks were able to access these leaves, whereas the giraffes with shorter necks couldn’t. This is why the short-necked gradually disappeared because of the absence of food, however, the giraffes with long necks did not die. In this instance grasses are not growing. It is an environmental issue which leads to the choice of more fit individuals, and the demise of those who are less fit.
Sexual selection in peacocks
Peacocks compete between male peacocks trying in search of a suitable partner. Male peacocks show natural selection, which is evident in beautiful and colorful tails that draw female peacocks. So, males who have dazzling tails succeed in attracting females , even though they are not able to replicate the male’s ability to eat or reproduce. So, males who have appealing tails are naturally preferred over those who have smaller tails. Similar mechanisms are observed in other species of birds, such as ducks and tropical birds , where males have more ornamentation than females.
What is Artificial selection?
- Artificial selection also known as selective breeding is which allows humans to recognize desirable characteristics in plants and animals and apply these traits to produce desirable traits through breeding.
- While the process of artificial selection is based on the same mechanism that is used in natural selection Artificial selection is controlled that is triggered by humans, while natural selection happens due to natural factors.
- Artificial selection is based on research done by Charles Darwin, where he found that selective breeding leads to beneficial changes over a long length of time.
- Contrary to the natural process of selection, artificial selection does not cause speciation or evolution.
- Artificial selection happens to be quicker process, and the results are observed over a few generations.
- Domesticated species of animals and plants are usually chosen based on their desirable traits in phenotypics to produce crossbred animals and plants.
- The selections are designed by farmers to ensure higher production and higher quality.
- Artificial selection for animals begins with purebred animals of only one trait and breed that are then crossed together with purebreds in order to enhance and maintain superior traits.
- Artificial selection in animals can be caused by inbreeding, outcrossing, or line breeding.
- The hybrids that result from selective breeding are more likely to have an increased vigor. This is known as hybrid vigor. However, there are times when these breeding can also lead to the loss of the quality.
- Similar processes are used to breeding plants, in which native plants can be domesticated to create an agricultural system that is predictable and uniform.
- The same procedure is employed for breeding plants, where plants that have houseful traits such as more production are bred to keep these traits, and also to develop traits that are superior.
- Plant breeding that is selective has been utilized throughout the ages to improve agricultural practices; today however, it is also utilized in the study of the homozygous nature of plants to many genes.
- Although the artificial selection process is managed, there are times when it can happen unintentionally in the process of farming, resulting in desired or undesirable results.
- The advantages of artificial breeding include increased productivity and healthier offspring, together with more efficient and speedier analysis of offsprings.
- However, there are certain disadvantages to artificial selection, as it can’t be carried out on a complete population at the same time and the process must be carried out under laboratory conditions or in the greenhouse.
- Artificial selection can also reduce the genetic diversity within the population since the most healthy species are crossed with one and increase the homozygous genotypes.
- A few examples of artificial selection are breeder breeding of dogs to produce the breed of dog that is new as well as cross-breeding for cash crops like rice and wheat.
Examples of artificial selection
The breeding of dogs is a typical thing, and it’s thought to be true that purebred breeds that are found today were artificially selected from 14,000 years ago. The ancient breeding was mostly done in order to create an easier, faster and more useful version of the ancestors that were already in existence. The dogs were improved to improve their chances of winning being hunted and to guard its human. As time passed, and humans started to consider keeping canines as their pets their goal was changed to protect the home and to ward off the intruders. As a result, greyhounds and dogs were interbred to produce strong and energetic types of breeds. Today dogs are kept at home and serve as pets for the majority of people. In the end, artificial breeding was evolved to produce more pleasant and more adorable dogs such as bulldogs and poodles.
Selection of cash crops
Genetically modified selection for crop varieties has been in practice for a lengthy time. It is believed that the common ancestor of all wheat species in existence in the present is the Triticum monococcumor einkorn grain initially cultivated in Asia around 40000 years ago. The plant was then crossed or inbred with species to increase the production and the variety of wheat. Today, various varieties of wheat are utilized for various purposes, such as beer production. The wheat used for beer production is different from the one used to make pasta and other types of noodles. The species are created by selecting specific varieties that can be used to serve their specific needs.
Key Differences between Natural selection and Artificial selection (Natural selection vs Artificial selection)
|Basis for Comparison
|Natural selection is the process that allows an organism to adapt to its environment’s changing conditions through the introduction of changes in the genotype of its genetic material.
|Artificial selection is also known as selective breeding that allows humans to identify desirable characteristics of animals and plants and then use these traits to produce desirable traits in phenotypes by breeding.
|Natural selection is an organic process.
|Artificial selection is a man-made or artificial procedure.
|Natural selection happens in natural populations under natural environments.
|Artificial selection is a common feature in domesticated groups put together by humans.
|The likelihood of survival of an organism that is fit improve as a result natural selection.
|The possibility of survival for an organism could be at risk if it is not handled in a correct manner.
|Natural selection can be described as a gradual process that is completed after a number of generations.
|Artificial Selection is an quicker process that is completed within days or weeks , with greater observable results.
|Natural selection isn’t as managed as synthetic selection, but natural processes regulate it.
|Artificial selection is more controlled by humans since they are in charge of it.
|Natural selection could be present in all living organisms on earth.
|Artificial selection is selective and may be used on specific species of animals and plants.
|Natural selection relies upon the adaptability of animals.
|Artificial selection relies on desired characters that humans select.
|Only traits that are beneficial or advantageous are passed on through the subsequent generations through natural selection.
|Artificial selection allows only the traits that are selected to be passed down through the successive generations.
|Natural selection influences the entire population of an animal species.
|Artificial selection only affects people who are selected.
|Natural selection is the cause of an abundance of diversity in the biological world.
|Artificial selection can only bring about desirable modifications and desirable traits, and results in a reduction in genetic diversity.
|Natural selection helps to create the evolution of species and evolves across many generations.
|Artificial selection doesn’t facilitate evolution.
|Natural selection has an impact in a broad-based way on the natural world.
|Artificial selection only affects the selected people who are financially important.
|Hybrid vigor can be seen in offsprings following natural selection.
|Hybrid vigor decreases during artificial selection due to preservation of traits that are desired.
|The natural selection process is an organic phenomenon, therefore no effort from humans is needed.
|The artificial choice could be costly and labor-intensive.
|Following natural selection the percentage of heterozygous genotypes increases.
|Following synthetic selection, the percentage of homozygous genotypes increases.
|A few examples of natural selection include the choice of giraffes with long necks as well as variations in the shape and size of the beaks of birds in relation to their eating habits.
|A few examples of artificial selection are breeder breeding of dogs to create the breed of dog that is new, and crossbreeding in cash crops such as rice and wheat.