Natural selection is a key foundation of evolution.
Random variations and mutations make some organisms better adapted for survival, allowing the improved characteristics to be passed on to succeeding generations, and ultimately creating new orders and species. A single type of life, if the probabilities of life forming are low. Highly specialized behaviors and complex physical adaptations evolving only once. Sonar must have evolved separately in porpoises and bats. Mutations adding genetic information, creating new and advantageous characteristics.