20/9/2015

I watched a video called Selection in Action. Both natural selection and artificial selection cause variation. I have learnt artificial and natural selection before but not as details as mentioned in this video. Artificial selection is a process where human make new species by selecting traits. The people in the past accidentally figured out that traits can be past from one generation to another and an animal or plant with desired traits can be selected to breed with another to produce the offspring with the desired characteristics. This can be explained by Mendelian inheritance pattern.

The examples given in the video are closed to our lives so I could understand that how artificial selection was practiced in our lives. The example was corn, the major agriculture crop in US and the major food source of human as well as animals. Artificial selection created tall plant corn which packed a lot of corn stalks.

  

Artificial selection also occurred in animals. Breeders who were interested in certain traits of a dog breed with another dog to produce desired new offspring. However during breeding, it was proven that it could be simple Mendelian gene or many other genes that control the same trait such as codominance, incomplete dominance, multiple alleles, polygenes, lethal alleles, linked gene and epistasis which I have learnt.

Natural selection caused the evolution of organisms. Sticklebacks were found to have undergone adaptive radiation which some have 2 spines, some have 1 spine and some have no spine. There were 40 different species of sticklebacks as they looked so different. Their teeth were modified to adapt to different food sources and their armours were different.

  

All in all, selections are good as they helped the organisms to adapt and survive better and improved the quality of the crops. Favourable trait will be selected and the less favourable trait will be eliminated. I think this lesson is important for our course because we have to understand what causes variation and how it’s carried out so that we could apply it in our future research. We could improve our lives with advance technology and our knowledge.