Life Sciences Biology 11 – Alexa Darwin – Mrs Mireau
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?
Darwin’s theory of evolution and propositions were a massive advancement for our world. We can see physical proof and physical documentation of the change in organisms from generation to generation, giving a clear pathway that we can trace back to see where we have come from and how far we have. It shows mutations and adaptations made to our environments in the physical form. It has changed the way we view evolution today because people now believe in the theory of evolution and importantly natural selection. It opened the world’s eyes to the fact that things change, on such a deep and profound level as the fibres that actually make up our bodies and the world around us. Before the ideology was solely based off of religious beliefs and texts, but now we can see the physical change and proof in organisms. It is also being used as a tool to look into the way we live life and to what quality and why. Looking towards the future and even now, there is so much work being done with DNA whether it be with genetic mutations and how it correlates to advancement and natural selection, illness, and even how we can move forward, stronger with amazing concepts such as regeneration and the role that DNA plays in that. I believe that our world would not be as far advanced as we are today, in a philosophical sense as well as a medical and scientific sense without Darwin’s theory and his massive discovery of the true importance and role of DNA its changes over time.
(Text and questions relating to specific example are put in bold and indented.)
There are important examples of the theory of evolution that are shown in Nova’s video, such as Darwin’s discoveries on the Galapagos islands. Specifically with the finches and the discovery that their beaks were formed the way they were and as diverse as they were because they individually served a specific purpose. All stemming from the same place, but evolving into something uniquely useful.
Another important discovery is that DNA does not stay the same. If it did, everything in creation would just be a carbon copy of itself. Mutations are responsible for the progressive change that we see in our world.
This is demonstrated with fossils and is clearly shown through the video with the correlation between pre-historic fish and our more advanced limbs. Mutations and which genes were switched on and off is what made those bones evolve into our leg and arm bones today. They were always there, but genes and evolution are what allowed them to progress to what they are, Darwin’s theory playing a huge role in those discoveries.
- Darwin was offered a position on the British Navy Ship, the HMS Beagle, whose mission was to survey the waters around South America.
- Where did Darwin make his first important discover? Argentina
- The Galapagos Islands are home to animals found no-where else on earth. (Where Darwin made his most important discoveries.)
- The upper shells of the giant tortoises differed depending upon which island they lived.
- The Galapagos finches different in the type of beak, depending on the island.
- Darwin realized, for some reason, that species change.
- Darwin studied dog breeders and how specific traits were selected. Darwin then wondered if a natural selection without human interference could be going on in life.
- The pattern in nature that Darwin saw was that the creatures that survived were those best adapted to the specific environments in which they lived.
- The Galapagos finches have different beaks because the finches used their beaks as tools.
- Darwin realized that variation was the start of change in nature.
- Over many generations, tiny variations allow the fit to get fitter and the unfit to vanish. This is evolution by natural selection.
- In 1859 Darwin published On The Origin of Species.
- Many genes get translated into proteins.
- DNA has one other vital quality. It doesn’t stay the same.
- Without mutation, everything would stay the same, generation after generation. We can now find the genes that are responsible for evolutionary change.
- Humans have 23 000 genes. The same numbers as a chicken and less that an ear of corn. Many of our key genes are similar to those other animals.
- How do you get all these differences if you have the same number of genes? The first clues are from the study of fruit flies. They are the platform of diversity and all sue the same basic genes.
- 98% percent of DNA doesn’t code for proteins.
- A piece of DNA called a switch is not a gene, but it turns “on” or “off” genes.
- What is special about the body plant gene? It throws a switch and tells the “stuff genes” what to do and when. This is how all forms of life are related, but evolved to become completely different.
- The bones of the human inner ear have developed from fish gills.
- Fossils show that creature with legs appeared million years ago. Before that , there were only fish.
- Dinosaurs share a common ancestor with birds. Fish share a common ancestor with all four-legged forms.
- The Archaeopteryx fossil had features of both birds and dinosaurs.
- Tiktaalik is a perfect transitional form: the body of a fish with scales, but also the bone structure is seen in all four-legged forms.
- The body plan genes called hawks genes are found in all complex animals from 600 million year worms to humans.
- The genes needed for arms and legs were in pre-historic fish. All they needed was a few mutations to change the order of what genes are turned on and off.
- There is a 99% percentage difference in the DNA of humans and chimps.
- The two signature organs of humankind are the hands and the brain.
- A mutation in the human jaw muscle allows the skull to keep expanding into adulthood, creating a bigger space for the brain.
- There are 21 different mutations responsible for microcephaly.
- A study of human and chimp DNA sequences show that the differences were in the actual genes, but in the switches that directed the genes. More than half of these switches are near a gene that involves the brain. That gene was different in 2 letters between the chimp and the chicken, but different in 18 letters when compare to humans.
- DNA works in many different ways – through genes that make the stuff of our bodies, through switches that turn those genes on and off, and through sequences of the DNA that throw those switches. This shows how small differences in DNA can generate enormous change.