​The Miami Dolphins followed their season-opening loss by attempting to step up in class for Week 2.But they got outclassed in all three phases of a 35-13 loss to the host San Francisco 49ers.If it wasn’t quarterback Brock Purdy having a near-perfect day passing and running, it was the 49ers’ defense having all the answers it needed for Malik Willis. And, finally, Miami’s special teams again failed to hold up its end with a blooper-reel of a mistake.A tight first half raised hopes for the Dolphins before a 21-point third-quarter blitz by the 49ers drove home what can happen when a veteran-laden team with Pro Bowl talent faces the youngest team in the league.Here are the takeaways:Edge is a major problem for this Dolphins team …We knew going into this season that the Dolphins were severely lacking on the edge.Then Chop Robinson went down with a concussion and was out for the 49ers game.That left pass-rush duties in the hands of rookie Max Llewellyn and Clelin Ferrell, who were elevated off the practice squad, Robert Beal, who suffered a hamstring injury; plus Malik Herring. Together, they had minimal impact on the game.At least Josh Uche had a handful of tackles and got his hands on Purdy.Even at full strength, the entire group has a long way to go to threaten quarterbacks such as Patrick Mahomes, who happens to be next up on the Dolphins’ schedule.… and so is assignment confusion in the secondaryAlthough the Dolphins trailed 14-6 at halftime, they had ample reason to feel like they were still in this game, dominating in several statistical categories.And it all fell apart in a flash.Pass coverage was the culprit as Miami suffered from blown assignments that allowed tight end George Kittle to catch two passes for 52 yards, including a 12-yard touchdown. Replays appeared to show that Kittle was Willie Gay’s responsibility.Regardless of whose man it was, confusion reigned in Miami’s defensive backfield, so it didn’t take long for the 49ers to turn a 21-6 lead into a 28-6 lead with blowout potential. Fullback Kyle Juszczyk was the lucky recipient of that TD pass, a 6-yarder.With so many new faces and youth in the secondary, issues were bound to pop up. Physical mismatches are going to happen. It’s the mental errors that are tougher to swallow.Malik Willis HAS to learn when to throw the ball awayWillis’ career as a starting quarterback is still in its infancy.Two of his best weapons are his legs. And it’s up to him and coaches to figure out how to take advantage of them.A week after pointing a finger at himself for five sacks, Willis took a bad sack in the red zone as a promising second drive stalled. The Dolphins ended up with a possession of 17 plays, 63 yards and eating up 9:21, but it produced only three points. We’ll never know what might have been had Willis thrown the ball away instead of taking that sack.Later in the first half, however, came a play that should become a Willis staple. He scrambled, eluding Nick Bosa whil