MELBOURNE, Australia — The Los Angeles Rams are like the kid who doesn’t study for the big exam, shows up at the last minute and hopes his natural talent and improvisational skills earn him a passing grade.And if that happens, it’ll leave his twin, the one who studied for a week, did all his homework and painstakingly made all the necessary preparations, mad as hell.Welcome, Australian fans, to 49ers versus Rams, which, with all due respect to Jim and John Harbaugh, is the NFL’s biggest sibling rivalry.The Seattle Seahawks might be the reigning champions of the NFL and the NFC West. They even smoked Super Bowl victory cigars inside San Francisco’s home locker room in February. But the 49ers and Rams aren’t nearly as obsessed with the Seahawks as they are with each other, largely because they’re so similar.Rams head coach Sean McVay, of course, learned his craft under Kyle Shanahan in Washington. They became head coaches at the same time in 2017; they run the same offense; they compete for the same players; they hire the same assistants. They’re the NFL versions of Cain and Abel.Which is why their divergent paths to the Southern Hemisphere stand out.The teams couldn’t have taken more different approaches. While the 49ers arrived one week ago and have done everything the league has wanted — visit coffee shops, attend a footie game, chat up Australian media members and otherwise make NFL inroads in a foreign land — the Rams haven’t done nearly as much.Their trip amounts to a pop-in. They had a media session and practice yesterday afternoon (Thursday, Melbourne time). They’ll show up for today’s three-hour contest at Melbourne Cricket Ground, then jet back to Los Angeles.“What gives me confidence is I’m not going to really make it a big deal,” McVay said this week about the team’s approach to the Australia trip. “It’s, ‘Hey, this is what the reality is. We’ve got a long way to go, but let’s be ready to rock when that three-hour window that we’re allotted comes.’”In that way, a loss might not be such a big deal for the Rams. They didn’t spend much time or many resources on the trip. They didn’t even take Aaron Donald.Lose to the 49ers and, like the kid who blew off the exam, the Rams can easily explain it away: “Bro, I barely studied! What’d you expect?”But if the 49ers lose?Oof.George Kittle, 49ers have enjoyed Australia visitMatt BarrowsThey spent a lot of time and many resources on the trip. They lost a starting player, defensive tackle Alfred Collins, who tore his patellar tendon in Tuesday’s practice. And their show-up-early strategy might put their Week 2 readiness in greater jeopardy, at least compared to Los Angeles.The Rams’ short turnaround means they’ll never have to adjust to a new time zone. When they return to Southern California, their bodies will still be tuned to Pacific Standard Time. They also play their Week 2 opponent, the New York Giants, on “Monday Night Football,” giving them an extra day to recover.The 49ers requested that Week 2 Monday game before the NFL schedule came out.“Yeah, we asked very nicely,” Shanahan said. “Didn’t work.”The 49ers flew to Australia early to get their bodies onto Melbourne time, a process Shanahan said took time.“It’s taken me a while to get adjusted here,” he said Wednesday. “I’ve been waking up at one in the morning — wide awake — every day until today. And I was extremely tired before this morning, which I feel is (when I) finally adjusted, which I think is five days.”He figures it’ll take five days to get back on California time, which the team will have. The 49ers arrive back in San Francisco on Friday afternoon. The first full practice won’t be until Wednesday.The final layer of this sibling rivalry is that the 49ers are convinced the Rams, the home team in Melbourne, handpicked the 49ers as their opponent to avoid the annual mass migration of 49ers fans to SoFi Stadium. Those games are so packed with red-clad 49ers fans that the Rams often have to use a silent count in their home when their opponent is in town. Moving the game to Australia also turns the 49ers’ shortest annual trip into the longest any NFL team has made in the regular season.It’s the kind of cheeky move only a brother would make.NFL teams like to say that intra-division games count double because a victory for one squad also brings a loss for the other. If the 49ers lose to the Rams, it might feel like more than that.