Take a long glance at the Buffalo Bills. Pay special attention this NFL season to the team's head coach and his twin brother. It is rare to watch a once dominant species go extinct, to see something that once helped define an ecosystem fade before your eyes and then, whoosh, vanish.

But that is what is now unfolding for the Ryan football family. Once proud, powerful and far-reaching, the Ryans are fading from the landscape their father helped craft.

This is not hyperbole. The Bills have been maligned by a rash of injuries, bad luck that may be the final straw in the family's fading legacy. Rex Ryan has already jumped the shark, professionally and off the field with that megawatt, over-the-top personality, and only winning can correct the downward slide. His brother, Rob Ryan, has as a defensive coordinator been on a run of marshaling mostly duds. In 12 seasons as a defensive coordinator, he's had just two successful defenses, the 2006 Raiders (sort of) and the 2013 Saints.

Now the Ryan brothers are both in Buffalo, together for what could be one last chance to preserve the family's relevance in a league quickly moving on without them.

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There's no joy in this. I like Rex Ryan, what he stands for and who he is, but good times and jolly moments and jokes about tattoos and toes don't cut it at this level. This isn't the local Elk's Lodge. This is the National Football League. Being the life of the party doesn't matter if you can't find a way to win football games.

It's equally unfortunate given the fact their father, Buddy Ryan, passed away this summer. A giant in the NFL, a man who literally molded NFL defenses in his vision and bent them to his will, who helped redefine the league, has gone. It is the difficult task for his sons to fill his NFL shoes. It's a task at which they're failing.

You think Rex Ryan, with all the distractions and missteps, gets yet another chance at one of the 32 most coveted jobs on Earth? You think his brother, who had to head closer to the family tree for employment, will have suitors beating down his door if the Bills' defense falters? Think again.

All royalty fades. Kings and queens rise, dominate, rewrite the world, then hand the throne and what they created off to their children, their children's children, the line unfolding. Until the line ends. Things change. Once great influencers diminish. Football royalty, like all kinds, has its advantages -- but inevitability and infinity aren't among them. Bad luck, braggadocio without the brilliance, the fine line between triumph and tiresomeness -- they can all conspire to end eras. As they are, right now, in Buffalo.

Linebacker Manny Lawson has a partially torn pectoral muscle, rookie Reggie Ragland had a season-ending injury, first-rounder Shaq Lawson is out for at least the first six weeks of the regular season. On and on the list goes, one injured Bill after another. The bad luck is certainly there.

But so is the mediocrity that can no longer carry the family name. Rex Ryan has been an NFL head coach for seven seasons. Care to guess how many winning seasons he's had? The unavoidable answer: Two. Just two seasons, all the way back in 2009 and 2010, when teams he led finished above .500.

You're a Sexy Rexy apologist? Cool. I get it. He's likable, a refreshing burst of candor in a league of too-serious football coaches. He has a great, maybe brilliant, defensive-football mind, just like his dad. That one winning season hasn't stopped him from twice knocking on the door of a Super Bowl berth. And certainly this year's rash of injuries rests well beyond his control. But it's equally true that having gone 8-8 in three of his head-coaching seasons -- see! you're wrong! he was so close! -- is simply an argument that mediocrity is some kind of accomplishment. It's not.

Not even for colorful, likable, bursting-from-the-seams personalities.

Not even for the scion of a great man like Buddy Ryan, the inventor of the 46 defense, the architect of the Purple People Eaters and the Bears' 1985 reincarnation of the Monsters of the Midway.

Not even for a Sexy Rexy.

He's nearing the end of his time as a head coach in this league. And it won't just be Rex. The Ryan family will pass into oblivion as well.

Rob Ryan is at the end of the plank. Rex Ryan has used up all that political capital of his headline-inducing charm. Buddy is gone.

That means the Ryan family's continued place as a staple of the NFL rests in the Buffalo Bills winning a lot of football games this season. Rex Ryan's history -- and Rob Ryan's past defenses -- tell us all we need to know.

That a football family is about to go from royalty to irrelevance.