Nobody knows exactly where the seeds of life came from.
Some believe the chemicals essential to life were brought here by meteorites, while others believe they arose naturally in the early oceans and atmosphere. But most researchers agree that carbon, hydrogen, oxygen, and nitrogen eventually linked up to form the basic molecules of life. Then, they slowly assembled into more and more complicated structures that could reproduce themselves. That set the stage for the blossoming of life. Luckily, due to random changes in their genetic codes, the flock produces a few newborn birds that have bigger beaks.