I'm not exactly sure of your question but here's what i think your asking, Darwin and scientists today have discovered that the ancient organisms whose remains they find look like organisms alive today because they are the living organisms' ancestors or evolved from a common ancestor. They provide valuable information about evolution and how life formed
What supports natural selection is that more organisms are born that survive: so that only the fittest would survive. The natural selection then selects the strongest individuals to surive and procreate.
