Early scientists of evolution did not explain major changes that created new how the species of organisms began. work in the 1890s first helped explain the question The of botanists genetic families in of evolutionary development. Hugo de vries studied a flower called the evening would appear in new plants were primrose. He noticed that sometimes traits parents of the that not there before. The trait could not be found anywhere in the gene. plant. De vries believed that it began of a specific because of a sudden change Genes are biological codes for inherited traits. They are passed from parents to offspring determine things such as hair color, paw size, or De vries that a change of this code introduces new characteristics, addition, these characteristics can 10 then be passed to future offspring. He called such hereditary changes mutations. People who study genes today understand mutations as a change in the order of deoxyribonucleic acid or DNA. DNA is made up of individual units called nucleotides. These nucleotides form long spiraling chains, The location of nucleotides along the DNA chain determines the characteristics of an organism. DNA provides the genetic information for living organisms in the same way that the hard drive of a computer carries information. Just as a picture on a computer screen becomes distorted when one changes its digital coding, a mutation happens when a specific sequence of DNA is altered. Mutations may involve the removing or changing of only one or a few nucleotides. The result, however, may be very ramatic