Natural Selection
The bat evolved from a very similar specie. The Chriacus(1) is a direct ancestor of the Little Brown bat. They evolved from a flightless bird to a bird with the ability to fly. The original bat was known to be very large and flightless, but over time this changed and bats are now small and have the ability to fly. The ability to be nocturnal also changed this.
(1) http://pterosaurheresies.wordpress.com/2011/09/21/the-origin-of-bats/
(1) http://pterosaurheresies.wordpress.com/2011/09/21/the-origin-of-bats/
Speciation
This organism had a allopatric speciation, meaning that different traits arose from the geographic change. Bats from South America are very different to bats from North America, because they have different climates and weather patterns. The movement of bats has created a diverse array of traits.
Taxonomy
Kingdom: Animalia
Phylum:Chordata
Class: Mammalia
Order: Chiroptera
Family: Vespertilionidae
Genus: Myotis
Specie: Myotis lucifigus
Phylum:Chordata
Class: Mammalia
Order: Chiroptera
Family: Vespertilionidae
Genus: Myotis
Specie: Myotis lucifigus