Positive mutations might lead to the organism having a better chance of survival, which means the mutation may be passed on to the offspring (this would only occur if the mutation is a germline mutation - occurs in sperm or ovum). However, positive mutations rarely ever, possibly never, occur.
Negative mutations may lead to an early death — probably before the organism can produce offspring. Many mutations are inert, meaning that they do not result in any changes to the protein produced by a specific gene.