Species is a group of organisms that are similar and can reproduce among them selves.It is the smallest unit of classification.All human beings belong to one species.
A gene is a unit of heredity.Parents pass on genes to their children.Genes control all charecetrs of an individual.
We look like our parents because parents pass on the genes to their children.Genes are present in the nucleus inside the chromosomes.
Gene is a unit of heredity formed chemically by DNA. Where as the species is a group of similar individuals.