Answer:
It sort of woke up the Union, The battle of Shiloh was one of the first major battles of the Civil war and told Union soldiers that The Condfederates were not playing around. As both Sides lost 1-2,000 Soldiers during this battle... It showed the Union the ruthlessness and aggresiveness of Confederate troops and how relentless they are. This showed them that the Rebel movement was serious and its not going to give up too easily! This could be debated as the Wake up during the war that told leaders: This is serious.