Because when you put a part of the DNA and take it out, you can restrict an ability of that cell. When you cut out a piece of DNA from a pancreas beta cell that codes for insulin synthesis, you restrict the cells ability to make insulin, hence the name "restriction enzyme". I hope this is the answer that you are looking for and it comes to your help.
The theory of evolution was proposed by Charles Darwin and was first formulated in his book, "Origin of Species" in 1859. It focuses on the changes in species and populations over time