Humans all have the same basic physical features but, with the exception of identical twins, everyone looks different. Every living organism has physical characteristics that set it apart from other individuals. All of these observable traits are passed down, or inherited, from a parent to its offspring. Although each species has unique characteristics, scientists have discovered that all living things share common ancestors. In fact, all life on Earth can be traced back to a single organism.
You can gain an understanding of genetics by studying your own family. Are there any unique traits specific to one or more members of your family, such as eye color? Make a chart and list the members of your family. As you read, choose or investigate four traits that interest you. Compare each family member and describe that trait for each individual. Are there traits common to all family members? Are some traits unique to one individual?