Final answer:
The similarity in DNA sequences among closely related organisms indicates common ancestry, reflecting a closer and more recent evolutionary connection derived from a shared ancestor.
Step-by-step explanation:
The fact that DNA sequences are more similar in more closely related organisms is evidence of common ancestry. This relationship indicates that organisms with highly similar DNA share a more recent evolutionary history and likely diverged from a common ancestor. This concept is illustrated through phylogenetics, where DNA sequence data are used to construct cladograms reflecting these relationships.
It is noted that comparing DNA sequences provides some of the strongest evidence of evolution from a common ancestor, as more similarities in the DNA sequence suggest a closer evolutionary relationship. Moreover, a very well conserved gene is often used in evolutionary studies because such genes show sequence similarity indicative of evolutionary relationships.
An example of convergent evolution would be the development of wings in insects and birds, which is a result of similar environmental pressures but not from a recent common ancestor. Conversely, homologous DNA sequences represent shared ancestry rather than convergent evolution.