Zindagi ...
Another way of looking at these passages in Mark (as well as with any other parts of the gospels) is to be cognisant of the time when it was written and the contexts.
Mark was written about 70 CE and differences had started to emerge within those Jewish communities. It is quite rational to see the (anonymous) writers throwing barbs at their own contemporary opponents, namely the emerging Rabbinic Jews.
Mark was written about the time of the destruction of the temple, so the Sadducees were suddenly deprived of their power and authority, enabling the Pharisees to exert themselves.
All writers had their eyes firmly fixed on their contemporary situation. They wrote for the purpose of influencing their own immediate community. None of them wrote a documentary history.
Doug