Organisms are able to pass their traits to offspring during reproduction. Inside every living organism, there are molecules of DNA that contain genetic information about that individual.
A double strand of DNA:
During reproduction, DNA information is passed from one generation to the next. Traits like dimples, freckles, or curly hair may have been passed to you from the DNA of your parents.
Scientific evidence supports the theory that small mutations over the course of millions of years is the reason there are many different types of organisms on earth.