How did the discovery of DNA prove that Darwin’s theory of evolution was correct and how does it change the way we view evolution today and into the future?
What is evolution and What is Darwin’s theory of it?
Before the 1800’s, Biblical philosophers thought all species came into existence at the same. During the 1800’s though, scientists started to believe that species were changing, and this process of modern organisms having come from ancient organisms is called evolution. Evolution is the process by which related population diverge from one another, giving rise to new species. Many scientists had different theories of how this happened but were wrong until Darwin had a theory. Charles Darwin was a British naturalist and in the 1800’s thought of a way for life to change called natural selection. He studied that organisms have physical traits and behaviours that allow them to survive and reproduce in their environment which Darwin called fitness. He thought fitness occurred through adaptation. This allows organisms to be better suited to their environment and be able to survive and reproduce and pass along their good fitness genes to their offspring.
How did the discovery of DNA prove that Darwin’s theory of evolution was correct?
DNA and genes are important for life on Earth and is what makes us all different. Every living organism has genes, but clearly not all organisms are the same. That’s because of mutation. A mutation occurs as our cells divide and bodies develop. For example, Adenine can be replaced with Guanine in a DNA sequence which can cause small changes that no one is aware of. But if mutations happen in cells that are passed down to children, they can cause big changes. Mutations can be good, though. For example, a white furred rock pocket mouse living in the desert has only a chance of survival by camouflaging into it’s environment, but the dark colour of the land in some areas makes them easy to spot by predators. Over time, the light mice living on dark rock turned into dark furred mouse and the light mice living on light rock stayed light. This is because of mutation that Michael Nachmann found. There were four places where the sequence of DNA was different in the dark mice than the light mice. When a mouse was born with these mutations then it grows dark fur. This is evolution and natural selection at work and shows that DNA and genes are responsible for evolutionary change.
There is still another way that DNA is related to evolutionary change and scientists proved it after questioning how even though humans have the same gets of genes how do we have so many differences? The study of embryos showed that the body plan genes determine where the head and limbs go, if they have legs, arms or wings. Therefore; its not the number of genes that matters it’s how you use them. A piece of DNA called a switch turn on and off the genes that make stuff. For example, some fruit flies have spots on their wings, and others have plain wings. Sean Carroll found out that when the genes that code for black wing spots were compared to the ones that don’t have spots they had the same sequence. But in the plain winged fly, a sequence outside of that gene, the switch, turned off the gene that coded for spots, therefore there are a species of fruit flies that don’t have spots on their wings. Switches explain more than that like how one creature can become another creature. Just like how the manatee that lost its hind legs, Lake Stickleback lost its spikes whereas the Ocean Stickleback still have theirs. David Kinsley and Dolph Schluter from Stanford University, realized after research, that the gene responsible for this is a body plan gene, but its identical in both ocean and lake Stickleback. The difference is a result from a section of DNA that was broken, a switch, and didn’t turn on the spikes gene. This lead to the realization by David Kingsley and his team that the stickleback losing its spikes is caused by the same thing that made manatees lose their legs. This proves that switches play such a significant role in evolution. Then, after research on Galapagos finches done by Cliff Tabin and Arkhat Abzhanov from Harvard Medical School, and how they have different beaks, it showed that the same genes were responsible for the beaks in all types of finch. They found out the only difference
is how much the gene is turned on and when it’s turned on. This is because body plan genes throw the switches that tell the stuff genes what to do and when. So, the body plan genes threw the switch to tell the genes that form the beak how to form the beak. This has significant effects on how different animal bodies are formed, and how transformations have occurred. This proves Darwin’s idea of the tree of life, that all life-forms are related, and over billions of years they have changed and evolved.
How does it change the way we view evolution today and in the future?
As I have said, the discovery of DNA has clearly proved Charles Darwin’s theory and has changed the way we view evolution today. Before Charles Darwin was proved correct through DNA, the fact that humans have evolved from fish and that certain animals have lost their legs was just a theory and much like a myth. For all we know, without the discovery of DNA proving Charles Darwin’s theory, then Jean Babtiste Lamark’s theory which was based on acquired characteristics could be what we believe today. But now with proof, the evolutionary process on how certain organisms came to be through natural selection can teach us about and help us with the present and future. Scientists are figuring out ways where they can use evolution to their advantage such as with genetically modifying things, especially animals, to help benefit the human population. This means genetic materials have been added, removed, neutralized, or modified to allow certain new characteristic to be expressed. They have been in study for decades for things like producing pharmaceutical products in milk, transplanting animal organs to humans, producing resistant mosquitos, and most importantly, used to improve farm animals for human consumption. In 1989, Newfoundland’s Memorial University conducted a research to transfer resistance to freezing into salmon and AquaBounty Technologies Inc. did the modification. They made Atlantic Salmon by inserting a gene from the chinook salmon to hurry its growth rate, so it can reach market size more quickly. This type of salmon, evolved from a normal salmon, has reproduced so many times to a point where the Atlantic salmon has doubled in two years. In other words, AquaBounty Technologies Inc. took a gene from the chinook salmon, inserted in into another salmon to make a new species of salmon that grow faster therefore lay eggs earlier and reproduce their new species of salmon. This is an example of evolution used in the present day. Now that evolution is being proved through DNA, scientists are using it in an advanced way to benefit life on earth. They are doing this by manipulating DNA sequences, and taking favourable genes from one species and inserting it into another species to make it a more efficient species that can benefit human life. With the amount of technology humans have created, its not surprising that it was used in this way. As for the future, the technology that is being produced can only lead to better discoveries. I believe more species are going to be “made” by science leading to a more proactive feeding source meaning food is going to be produced quicker and more efficiently. Overall, the discovery of DNA proving Charles Darwin’s theory was important because if scientists today didn’t know genetics was the main factor in changing animals then they wouldn’t be able to manipulate that fact to make certain animals have specific characteristics of scientists choosing.
Citation.
What Darwin Never Knew. Produced by Matthew Barrett. 2011. DVD
Finnigan, Pat. “Figure 2f From: Irimia R, Gottschling M (2016) Taxonomic Revision of Rochefortia Sw. (Ehretiaceae, Boraginales). Biodiversity Data Journal 4: E7720. Https://doi.org/10.3897/BDJ.4.e7720.” GENETICALLY MODIFIED ANIMALS FOR HUMAN CONSUMPTION, December 2016, 1-19. Accessed October 8, 2018. doi:10.3897/bdj.4.e7720.figure2f