Bluetooth File Transfer is not just for copying files between two devices, you can also use it to edit, create, delete, move and rename files, either on your device, or another Bluetooth-enabled device, such as a PC, smartphone, PDA, or a music player.
Meaning and definition of bottleneck effect : Genetic drift resulting from the reduction of a population, typically by a natural disaster, such that the surviving population is no longer genetically representative of the original population.
This article is a good article explaining how the founder effects affect genetic drift. An example of a bottleneck effect: Northern elephant seals have reduced genetic variation most likely due to being hunted. Hunting reduced their population size to as few as 20 individuals at the end if the 19th century.