But the Earth is around 4.5 billion years old an humans have only existed for a tiny fraction of that time. We can see clear stages where creatures become less and similar to us as we go back in time. We can look at DNA and see a commonality with creatures who we believe spilt from us more recently. There is no missing link and we will never have the complete picture but the evidence of change over time and the appearance and disappearance of species over time is solid. There is no other valid explanation and the Hebrew creation myth matches the evidence about as well the Greek myth.