Life zone
![Holdridge life zone classification scheme. Although conceived as three-dimensional by its originator, is usually shown as a two-dimensional array of hexagons in a triangular frame.](/Images/godic/202412/24/Lifezones_Pengo.svg0204.png")
The Life Zone concept was developed by C. Hart Merriam in 1889 as a means of describing areas with similar plant and animal communities. Merriam observed that the changes in these communities with an increase in latitude at a constant elevation are similar to the changes seen with an increase in elevation at a constant latitude.