The evolution of Android

Android 1.1

Android 1.5 (Cupcake) Based on Linux Kernel 2.6.27
Support screen densities and resolution

• QVGA (240x320, low density, small screen)
• HVGA (320x480, medium density, normal screen)

Android 1.6 (Donut) Based on Linux Kernel 2.6.29

• Quick Search Box for Android
• Updated search experience to allow searching bookmarks, history, contacts, and the web from the home screen
• An integrated camera, camcorder, and gallery interface
• Battery usage indicator
• Updated technology support for CDMA/EVDO, 802.1x, VPNs, and a TTS engine
• Gesture framework and GestureBuilder development tool

Support screen densities and resolution

• QVGA (240x320, low density, small screen)
• HVGA (320x480, medium density, normal screen)
• WVGA800 (480x800, high density, normal screen)
• WVGA854 (480x854, high density, normal screen)

Android 2.0/2.1 (Éclair) Based on Linux Kernel 2.6.29

• Revamped UI
• Contacts and accounts
• New contact lists
• Multiple accounts can be added to a device for email and contact sync.
• Live Wallpapers
• Bluetooth
• Bluetooth 2.1
• New BT profiles: Object Push Profile(OPP) & Phone Book Access Profile(PBAP)
• New Browser UI and HTML5 support
• Camera
• Built in flash support
• Digital zoom, Scene mode, White balance, Color effect, and Macro focus
• Microsoft Exchange support

Support screen densities and resolution

• QVGA (240x320, low density, small screen)
• WQVGA (240x400, low density, normal screen)
• FWQVGA (240x432, low density, normal screen)
• HVGA (320x480, medium desnity, normal screen)
• WVGA800 (480x800, high density, normal screen)
• WVGA854 (480x854, high density, normal screen)

Android 2.2 (Froyo, Frozen Yogurt) Based on Linux Kernel 2.6.32

• Adobe Flash 10.1 support
• General Android OS speed, memory, and performance optimizations
• Integration of Chrome's V8 JavaScript engine into the Browser application
• Additional application speed improvements courtesy of JIT implementation
• Kernel Memory Management Boost
• Increased Microsoft Exchange support
• Improved security, Remote wipe, Exchange calendars, and Global address lists look-up
• Added an option to disable data access over mobile network
• USB tethering and Wi-Fi hotspot functionality
• Voice dialing and contact sharing over Bluetooth
• Support for file upload fields in the Browser application
• Support for installing applications to the expandable memory (APP2SD)

Support screen densities and resolution

• QVGA (240x320, low density, small screen)
• WQVGA (240x400, low density, normal screen)
• FWQVGA (240x432, low density, normal screen)
• HVGA (320x480, medium density, normal screen)
• WVGA800 (480x800, high density, normal screen)
• WVGA854 (480x854, high density, normal screen)

Android 2.3 (Gingerbread) Based on Linux Kernel 2.6.35

• Game Development
• Concurrent garbage collection
• Improved Event processing
• New sensors
• Gyroscope, rotation vector, linear acceleration, gravity, and barometer
• Multimedia
• Support WebM/VP8 video playback, and AAC/AMR audio encoding
• audio effects
• New Forms of Communication
• Near-field communications (NFC)
• UI refinements for simplicity and speed
• Redesigned multi-touch software ketboard
• System-wide copy-paste functionalities
• Native support for SIP VoIP telephony
• Support for video calls

Support screen densities and resolution

• QVGA (240x320, low density, small screen)
• WQVGA (240x400, low density, normal screen)
• FWQVGA (240x432, low density, normal screen)
• HVGA (320x480, medium density, normal screen)
• WVGA800 (480x800, high density, normal screen)
• WVGA854 (480x854, high density, normal screen)

Android 3.0 (Honeycomb)

Android ? (Ice Cream)

Reference:
http://en.wikipedia.org/wiki/Android_(operating_system)
http://developer.android.com/sdk/index.html