The evolutionary concept of descent with modification, aided by the ability to map these processes genetically, allows scientists to create a picture of evolution for organisms they can no longer study directly. Though current scientists are not able to study the genomes of most now-extinct ancestors of modern organisms, footprints of past generations can be observed in the genetic code of modern organisms. Additionally, fossil records and deduction based on observations of still-living organisms can fill in the gaps. The concept of descent with modification informs the logical process when such deduction is required. By generally understanding how and why traits emerge within a population and what impacts their probability of being passed down, we can work backwards from modern organisms and cover time periods or phylogenic branches for which we do not have other data.
Work Step by Step
Your essay may vary, but it should include a few key points. You should address how both genetic and observational data can inform the creation of a phylogenic tree for now-extinct organisms, as well as how each approach can help support and/or correct the other.