If each human cell has all the information required to build a human body, how can the information in those cells produce anything other than a human body? |
Sperm and egg cells do not have all the information needed to build a human body. When they combine to create a new genome, they create a genome that has never existed before. If you want to call it a wolf, Chihuahua, human, or whatever, that is up to you. What is important is that this organism with this genome has never existed before.
Over time, mutations in each generation will keep accumulating. When you compare individuals that lived millions of years apart there may very well be differences between them. At one point does one become the other? That is entirely arbitrary.
When does someone go from young to old? When does a young man go from being short to being tall? Skinny to fat, and maybe back to skinny? These are spectrums, just as evolutionary change is.