Artificial selection has resulted in plants that are more-disease resistant, cows that produce more milk, and racehorses that run faster. One must wonder what will come next. Under what circumstances should humans be artificially selecting plants or animals?
What is Artificial Selection?
First of all, what is artificial selection? According to an online dictionary, artificial selection, also known as selective breeding, describes deliberate breeding for certain traits, or combinations of traits. The term was developed by Charles Darwin, to distinguish it from natural selection. In natural selection, the environment is like a filter which only a few variations can pass through where as in artificial selection, humans favor specific traits.
Natural selection vs. Artificial Selection
Natural selection plays a very important role in evolution. In this process of natural selection, only the organism that are best adapted to their environment will survive and pass on their genetic characteristics to the next generation. Organisms that are not adapting as well to the physical and biological changes in the environment are eliminated.
One example of natural selection is the color of the Gypsy Moths in England. It is a good example of how when there is a quick change in the environment, a species has the ability to adapt. When an industrial revolution took place, industrial factories, such as coal factories, emitted massive amounts of pollutants into the air. There was so much pollution that the skies we dark during the day, as if it was night. The original color of the gypsy moths was light gray. This allowed them to blend in with the trees, which had light gray bark, protecting them from predators. However, when the change in the environment occurred, their camouflage no longer helped them. The tree bark became darker because of the pollution. Now those few dark gray gypsy moths were now at an advantage and the light gray ones were eaten by predators. As a result, through adaptation and natural selection, the gypsy moth was able to slowly change it light gray color to a dark gray color.
Artificial selection is when we “humans” take on the role as the “environmental pressure” causing the organism to adapt. It is pretty easy to accomplish. First, a specific plant or animal is chosen because of its specific heritable genetic trait that is desired. The plant or animal is then bred wit
h another of its kind with a similar trait. This results in offspring that have a higher potential to display the desired trait. This cycle can be repeated over and over again with the offspring until the desired trait is achieved.
One major example of artificial selection is the breeding of dogs. All the domestic dogs we see today, although very different in appearance, from Chihuahua to the Great Dane, all belong to the same species, Canis domesticus. They all originated from the same ancestor, the wolf. However, thanks to artificial selection, we were able to select certain traits, and created a variety of dogs that differ in appearance and behavior. Dogs such as the Dachshunds and Greyhounds both descend from the same ancestral wild dogs. However, both breeds of dogs were created by artificial selection. In the Dachshunds’ case, the process resulted in low and elongated bodies. For the Greyhounds, the process resulted in swiftness in running.
Another example is artificial selection in plants. Early farmers cultivated many well known vegetables from Brassica oleracea, which is wild cabbage. By artificially selecting for certain traits, common vegetables such as cabbage, broccoli, cauliflower and Brussels sprouts are all descendants of the wild cabbage. For exam
ple, broccoli was bred by selecting for large flower stalks. Brussels sprouts were created by artificially selecting for large bud size.
Advantages of Artificial Selection
Sooner or later, artificial selection is going to play a major role in our lives. There are many benefits that can come from this. Using artificial selection, disease can be prevented. All that needs to be done is to detect the people, animals or plants that are more likely to carry hereditary diseases and eliminating them. People, such as breeders of animals and plants, are looking to create organism that will have desirable characteristics. These include high crop yield, resistance to disease, high growth rate and many other characteristics that will benefit not only the organism, but humans in the long run. The process of artificial selection has made it possible for our species to i
ncrease the effectiveness of the animals and plants we breed. Using artificial selection we can create cows that produce more milk, crops that are more disease resistant, chickens that produce more eggs and even racehorses that run faster. How can these not considered benefits of artificial selection? With crops that are more disease resistant, cows that produce more milk and chickens that produce more eggs, businesses can expand and improve. They will be able to sell more, make more money, which benefits the economy and society as a whole. Another advantage of artificial selection is its efficiency. Artificial is way more convenient and efficient than natural selection. Natural selection happens naturally, over time. It can even take as long as a few thousand years for it to occur. Artificial selection can be done whenever needed, easily and quickly.
Disadvantages of Artificial Selection
Although there are many major advantages of artificial selection, it still has its many disadvantages. One of the dangers that can arise from artificial selection is inbred offspring. Some of the traits that are desired are so rare that they exist only between one or two families. When the trait happens to be recessive, two members of the same family line may have to breed together in order for the trait to be expressed. In animals, this can cause genetic defects and many other serious problems. For example, Dairy cattle are bred in order to produce more milk. However, some family lines can suffer from increased infections and fertility problems. Persian cats are bred for their particularly flat faces. Unfortunately, they often develop respiratory problems and can have trouble eating. Not only does artificial selection take a negative toll on the heath of the animals, but it takes a negative toll on our world’s diversity. If every animal was created by choosing only the desirable traits, there would be no diversity. It can also permanently 
eliminate many of the unwanted genes from the gene pool. To humans, many desirable traits are considered those who affect the appearance of the animal. They do not care about the genes that will help them adapt and survive. If all of the organisms had the same “desirable” traits, then one major change in the environment could wipe them out completely. The wipe out of a species would then throw the world’s ecosystems out of balance.
Conclusion
Now that we have covered the advantages and disadvantages of artificial selection, there is only one question left to ask. Is it ethical? If humans can already “design” what kind of animals and plants exist in the world, how much further can they go? The answer is, much further. As discussed in a previous topic, humans have already started “designing” their own babies. Just like choosing whether a cow will produce more milk or a plant will resist disease, humans can choose if their babies will be disease free and have blue eyes. Under what circumstances should humans be artificially selecting plants and animals, if any? Although there are many advantages, as I mentioned before, I still think it is ethically wrong to be artificially creating plants and animals. Humans are choosing to overlook the disadvantages and focus on the advantages. However, these disadvantages will become a major problem in the future. The main purpose of artificial selection is to produce offspring with a higher chance of carrying desirable traits. However, the measures taken to do this are actually causing the offspring to suffer. They are now developing genetic mutations and defects, because of problems such as inbreeding. The point was to create perfect animals and plants, but they are becoming less and less perfect. It kind of defeats the whole purpose of artificial selection.
There was a time when the world was mysterious and everything was left up to chance and nature. Today, science has taken over. Technology has overruled the mystery and might of nature. The world is slowly becoming like a factory, where everything is made the same. Soon there will be no more variety and diversity. The beauty of nature and out planet is slowly fading away.
Natural and Artificial Selection: Mechanism of Evolution: Biological Change in Wild & Domestic Animals http://geneticsevolution.suite101.com/article.cfm/natural_and_artificial_selection#ixzz0d6gTS9Xi
http://www.brighthub.com/science/genetics/articles/47262.aspx#ixzz0d6bpKfuZ
http://www.mnsu.edu/emuseum/biology/evolution/genetics/naturalselection.html
http://en.wikipedia.org/wiki/Common_descent#Wild_cabbage
Natural and Artificial Selection: Mechanism of Evolution: Biological Change in Wild & Domestic Animals http://geneticsevolution.suite101.com/article.cfm/natural_and_artificial_selection#ixzz0d6ZMc7gs
http://wiki.answers.com/Q/Advantages_and_disadvantages_of_selective_breeding
