Species and populations are probably the two most commonly used ecology terms, but they are often difficult concepts to grasp. Throughout this chapter, they will be discussed in detail, expanding on the definitions from previous chapters and explaining why there are no universally acceptable definitions.
Jefferson County, Arkansas is a county located in the U.S. state of Arkansas in the area known as the Arkansas Delta, that extends west of the Mississippi River. As of the 2010 census, the population was 77,435. Its county seat and largest city is Pine Bluff. Jefferson County is Arkansas's 21st county, formed on November 2, 1829, from portions of Arkansas and Pulaski counties, and named for Thomas Jefferson, third President of the United States.
Not to be confused with Washington, Arkansas. Washington County is a county located in the northwest part of the U.S. state of Arkansas. As of the 2010 census, the population was 203,065, making it the third-most populous county in Arkansas. The county seat is Fayetteville. It is Arkansas's 17th county, formed on October 17, 1828, and named for George Washington, the first President of the United States. Washington County is part of the Fayetteville-Springdale-Rogers, AR-MO Metropolitan Statistical Area.