The sentence may be a little ill-formed, but the general point is true. There are genes like the ones that cause Tay Sachs disease and sickle cell anemia, that have genetic advantages, like resistance to TB or malaria. But in the absence of the selecting force, such as with modern day medicine, the frequency of those genes in populations decrease over generations, which is the definition of evolution.
Sleeping seems like a huge disadvantage over a creature that could stay active and hunt 24 hours a day^, but if there were no selective force for creatures that sleep, creatures would evolve that don't require sleep pretty quickly. I'm not sure how fast, but the change would be observable over a couple of generations.
^(This advantage is not necessarily true in all cases. Bears sleep because it's not energy efficient to forage in the winter, humans may have evolved sleep as a way to save energy during the night because electric lighting became popular. However, I really doubt this hypothesis because of the number of critical functions that degrade under sleep, as well as the increased risk of heart problems from people who don't sleep a lot, which is really independent of whether you feel tired or not.)
On an unrelated note, how do you escape asterisks?
^(This advantage is not necessarily true in all cases. Bears sleep because it's not energy efficient to forage in the winter, humans may have evolved sleep as a way to save energy during the night because electric lighting became popular. However, I really doubt this hypothesis because of the number of critical functions that degrade under sleep, as well as the increased risk of heart problems from people who don't sleep a lot, which is really independent of whether you feel tired or not.)
On an unrelated note, how do you escape asterisks?