Natural selection will only cause evolution if there is enough genetic variation in a population. Before the discovery of Mendelian genetics, one common hypothesis was blending inheritance. But with blending inheritance, genetic variance would be rapidly lost, making evolution by natural selection implausible.
Amazon Kindle Fire (2012) The Kindle Fire has a multitouch-capable 7-inch IPS display, a dual-core processor, and at 14.6 ounces, a pretty lightweight frame. The resolution on that screen is 1024 x 600. The battery is rated to last for eight hours of continuous reading or 7.5 hours of video playback (with WiFi switched off).
However the key bonus for the Kindle Fire HD 7 is that it comes with 16GB of internal storage for $199 and not 8GB like the Nexus 7. The bigger model has double that of the bigger Nexus 7 with the Kindle sporting 32GB while the biggest Nexus only holds 16GB.