Over the past centuries, thousands of plants and animals have been introduced into the United States. Many of which provide us with a stable source of food and resources each day. During the “dustbowl” era of the 1930's, crested wheatgrass (Agropyron sp.) is credited with salvaging vast areas of deteriorated rangelands and abandoned cropland, but today is listed on the invasive species list. In an attempt to safeguard the United States from invasive species introductions, in 1999 the President of the United States signed Executive Order 13112. This order defined an invasive species as an alien species whose introduction does, or is likely to, cause economic or environmental harm or harm to human health. Invasive plants, animals, and pathogens have often reduced the economic productivity and ecological integrity of agriculture, forestry, and the Nation's other natural resources. This presentation will give examples of invasive species the Why, How, and Why Not from a genetic prospective. Possible characteristics that enhance the potential of plants (i.e., grass) to become invasive species will be presented.