In the seventeenth century, it was held by some that inside a human sperm there was a minute human being - a homunculus - that was planted inside the womb. Development consisted of the miniature homunculus enlarging and passing through birth and on to maturity-just like inflating a balloon.
Top 12 Quotes by John Tyler Bonner
There are good reasons why natural selection has become widely accepted as an explanation of evolutionary development. When applied to mammals and other large animals, it fits perfectly. But we cannot assume that all evolutionary steps arise from selection, particularly when looking at smaller animals.