Strange creatures slithering up from the Rub' al Khali desert floor in the Arabian Peninsula are really a network of barchan dunes—sculpted by winds that over time strike the sand from a consistent direction.
This powerpoint has images to go with Harcourt Grd 3 Science Chapter Lesson What are some types of ecosystems? Includes Desert, grassland, forest, freshwater and saltwater including animals and vegitation.
Crescent dunes, These are the fastest moving dunes and are formed by the wind continuously coming from one direction. The barchan dune can be found in the Great Sand Sea but is most common near the Dakhla and Al-Kharga Oases.