Artificial Selection
5/31/10
Artificial selection has resulted in plants that are more disease-resistant, cows that produce more milk, and racehorse that run faster. One must wonder what will come next. In the blog entry answer the following question – under what circumstances should humans be artificially selecting plants or animals, if any?_____________________________________________________________________________________
To probe into this issue, we must first define what artificial selection is in contrast to natural selection. Artificial selection is human intervention in animal or plant reproduction to ensure that certain desirable traits are represented in successive generations. Natural selection is the process in nature in which only the organisms that are best adapted to their environment tends to survive and transmit their genetic characteristics to the next generation. The studies of Gregor Mendel of Monohybrid and Dihybrid crossing and Charles Darwin’s study of evolution and natural selection gave us the knowledge to manipulate the genetic phenotypes of an offspring by selective breeding in animals and plants.
Artificial selection is achieved by altering the DNA of a species or by crossing the dominant alleles for particular genes. Since both species have dominant genes for the desirable characteristics, the cross will produce at least some offspring that will show all of the desirable traits. The offspring is called a hybrid, produce from two genetically dissimilar parents which usually produces offspring with more desirable qualities.
Examples of Artificial Selection
All modern domestic dogs, no matter how different they are in appearance, from Chihuahua to Great Dane, all belong to the same species, Canis domesticus. The originator of today’s domestic dog would have been an ancestral, wolf-like canine, and by intensifying selecting for certain traits, we have created a variety of dogs that differ widely causing a great diversity of body type, size, and coloration. Cats and dogs, which were originally domesticated for pest control, hunting, or shepherding, eventually were bred to become companion animals.
Artificial selection also occurs in plants. With the dawn of agriculture, about 10, 000 years ago, humans began modifying wild plants. Planting seeds from the most desirable plants is a way of choosing certain
genetic traits over others. Crop yields have risen dramatically since the advent of scientific crop selection. Today, DNA sequencing provides new tools for understanding crop traits and for selecting desirable traits with even greater efficiency. Let’s take our modern day to corn for example. Corn did not exist instead it was known as a wild crop called Teosinte. Corn ancestors did not have large ears. Instead they were hard, nut-like kernels, and feathery cobs. Corn today comes in many varieties, all of which have ear that contain many soft kernels. Thanks, to artificial selection the modern day corn has evolved from an undesirable and not edible Teosinte to a delicious corn. The goal of plant breeding, scientific crop selection, and modern genetic research is to increase crop yields and improve the quality of the food, feed, and fibers produced. Modern crops are dramatically more productive than wild plants.Humans have had an overwhelming influence on the environment in which they live in and share with many species. One of the major steps of the development of our civilization is through selective breeding of plant and animal species for food and labour. In today’s agriculture, c
orn, wheat, and soybeans have resulted from careful breeding. The vegetables that we eat are a result from farmers’ selective breeding. For example, broccoli, cabbage, cauliflower, Brussels sprouts, collards, and kale are all members of the same species, the Brassica oleracea. Through artificial selection a variety of these vegetables has been produced. The meats we eat are a result of the careful selective breeding of cows, pigs, sheep and chickens. They have been genetically enhanced to produce more meat. What does this impose to our society? The more meat that a domesticated animal can produce brings more income to a farmer’s table. Thus, the demand for more meat and produce are met and the consumers are satisfied. In addition, with selective breeding we are able to take wild grasses and grains and selectively breed them to produce greater yields. We bred cattle, sheep and horses to be larger, stronger and more submissive. We even bred wolves to help us maintain and defend these other animals.
Well, I was able to depict the positive influence of artificial selection within our society and the changes that it brought. Now, let’s take a look at the negatives of selective breeding in a few examples.
Artificial selection can cause problem traits to predominate in a species. For example, Dobermans are a breed of dog that has been bred to produce a certain appearance. During the process of selective breeding to achieve this appearance, a genetic defect has evolved and increased in the population. This defect causes narcolepsy, a condition that causes these dogs to uncontrollably fall into deep sleep. This condition does not increase the species fitness or desirable characteristics. If natural selection occurred, this conditioned would have been prevented. However, due to artificial selection these animals will acquire this defect for the following generations.
Artificial selection has brought a lot of income to a farmer’s table and satisfies the consumers demand for more meat, milk, and food. However, does artificial selection provide us with healthy food? There was this myth about “KFC” genetically manufacturing their chickens to produce more meat. Is this fact or fiction? Studies from the University of New Hampshire proved that the chicken “KFC” sells are kept alive by tubes inserted into their bodies to pump blood and nutrients throughout their structure. They have no beaks, no feathers, and no feet. Their bone structure is altered to shrink to get more meat out of them. This allows “KFC” to buy so much more for less production costs. These food are completely unnatural. In addition, these changes in features of the chicken can result to more disease and harm. They are prone to more diseases and parasites without protection from their feathers. Technically, are they even chickens?
Look at this picture of a genetic engineered chicken. Doesn't it disturb you? It sure distrubs me. I mean, we eat this? Is that even considered a chicken? After this, I don't see eating "KFC" chickens again.
orn, wheat, and soybeans have resulted from careful breeding. The vegetables that we eat are a result from farmers’ selective breeding. For example, broccoli, cabbage, cauliflower, Brussels sprouts, collards, and kale are all members of the same species, the Brassica oleracea. Through artificial selection a variety of these vegetables has been produced. The meats we eat are a result of the careful selective breeding of cows, pigs, sheep and chickens. They have been genetically enhanced to produce more meat. What does this impose to our society? The more meat that a domesticated animal can produce brings more income to a farmer’s table. Thus, the demand for more meat and produce are met and the consumers are satisfied. In addition, with selective breeding we are able to take wild grasses and grains and selectively breed them to produce greater yields. We bred cattle, sheep and horses to be larger, stronger and more submissive. We even bred wolves to help us maintain and defend these other animals.Well, I was able to depict the positive influence of artificial selection within our society and the changes that it brought. Now, let’s take a look at the negatives of selective breeding in a few examples.
Artificial selection can cause problem traits to predominate in a species. For example, Dobermans are a breed of dog that has been bred to produce a certain appearance. During the process of selective breeding to achieve this appearance, a genetic defect has evolved and increased in the population. This defect causes narcolepsy, a condition that causes these dogs to uncontrollably fall into deep sleep. This condition does not increase the species fitness or desirable characteristics. If natural selection occurred, this conditioned would have been prevented. However, due to artificial selection these animals will acquire this defect for the following generations.
Artificial selection has brought a lot of income to a farmer’s table and satisfies the consumers demand for more meat, milk, and food. However, does artificial selection provide us with healthy food? There was this myth about “KFC” genetically manufacturing their chickens to produce more meat. Is this fact or fiction? Studies from the University of New Hampshire proved that the chicken “KFC” sells are kept alive by tubes inserted into their bodies to pump blood and nutrients throughout their structure. They have no beaks, no feathers, and no feet. Their bone structure is altered to shrink to get more meat out of them. This allows “KFC” to buy so much more for less production costs. These food are completely unnatural. In addition, these changes in features of the chicken can result to more disease and harm. They are prone to more diseases and parasites without protection from their feathers. Technically, are they even chickens?
Look at this picture of a genetic engineered chicken. Doesn't it disturb you? It sure distrubs me. I mean, we eat this? Is that even considered a chicken? After this, I don't see eating "KFC" chickens again. Final Thoughts
Think about it, is artificial selection morally just or morally wrong? Some may wonder, though artificially selection has brought a lot to the development of our world, where do we draw the line? Personally, I believe that artificial selection in plants are very beneficial to humans, we have produced corns from Teosinte and several variations of vegetables from one species. However, artificial selection in animals is a different story. The demand for more and more turns humans into selfish individuals only to please them. We intervene with an animals’ natural selection to artificially select their genes to provide us with what we need. We do this to satisfy all our needs even it causes animal harm. Though, it is a win-win situation that we get more food, more money, and more variety, humans shouldn’t take advantage of this given gift.
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