I think the reason we have nails is to protect our fingertips mostly. Also the little bit of nail allows us to make more specialised movements. Imagine if we only had stubs for fingersI I think we’d find it very hard to open a can of coke or text!
I think we have nails because they are useful! As cat said how else would you open a can of coke or peel an orange! Also we might have nails because whatever we evolved from had some form of claw and our nails are kind of a remnant of these claws that we have kept because they are useful.
Hope this help
Most people believe in evolution and I certainly do so I guess the reason must come from whatever situations our ancestors found themselves in. We have evolved through monkeys who live in trees so maybe they or what ever monkeys evolved from needed them to climb trees to escape predators or tear food to pieces as they did not have knives. Our fingernails are maybe less important to humans than they were to our ancestors but its something that we have kept??
We have nails for similar reasons to what Cat, Pam and Holly said. Basically they are useful and protective. Humans are very special because of our intelligence and ability to use tools, and so we have evolved and adapted good ways to use them. I think the fact that we have nails means they are important to us, and if they are not important now, they certainly were in the past!
Sharp and hard items like nails allow us to open food – think of fruit, and nuts. They probably had a very important role in our diet in the past! And they are useful now, as Cat says for opening coke (hopefully diet coke ;)) and using technology like phones and keyboards!