Example- If you are studying insects, you should know how the Hox genes set the body pattern and how it arose from simpler body patterns so you can know the interrelation of the various genus, species, and families. You should also know that these same genes determine the body pattern in humans.
Another example- the human immune system. If you study it, then you have to learn something about the mouse immune system. Parts that are in the human system are absent or in a more rudimentary state in the mouse You have to know evolution to help you understand how it arose.
Evolution leaves its traces in the DNA.
I studied DNA replication in baker's yeast in grad school. We did it in yeast because they are easy to grow and and get the DNA out of them. Also, some of the corresponding human genes could be placed in yeast and still work fine. The human cell cycle genes were isolated this way. A lot of the active sites in these enzymes (where the actual chemical reactions took place were very conserved through evolution.
If I wasn't taught evolution, this would seem like magic.
Both Nobel Prizes (Medicine and Chemistry)involved an understanding of evolution for the work to be done. They involved telomeres- (at the ends of chromosomes-stops them from unraveling)(Medicine) and ribosomes (the machinery that synthesizes all proteins in all living things)(Chemistry).By looking at the DNA sequences, one can see how the organisms are related and how the DNA sequences changed during evolution.