Our Common Ancestors

In this chapter of The Selfish Gene I came back to something that I had studied in biology last semester, common ancestry. There are 6 kingdoms in taxonomy and each of this are very different from the others. The thing that makes us similar are our building blocks, the building blocks of nature DNA. Every organism on earth  started as the replication of DNA. We all have DNA from the simplest bacteria to humans we all have this building blocks in our systems. This idea of every organism in earth has DNA is a key to the idea of common ancestry. It is huge to think that since the origins of life, living organisms have had DNA, and we about 14 billion years later we are still made up of DNA molecules. This shows the relationship that every organism that has lived on the planet. It shows how the theory of common ancestry is true. If every organism now has DNA molecules in it so this means that once every organism on earth was the same and due to evolution and exposure to different habitats they diversified. Loosing some characteristics but keeping the most important feature, the key to life which is DNA.