In what year did the Toronto Blue Jays franchise play its first season?

In what year did the New York Mets franchise play its first season? In what year did the Houston Astros franchise play its first season? In what year did the Kansas City Royals franchise play its first season? In what year did the San Diego Padres franchise play its first season? In what year did the Seattle Mariners franchise play its first season? In what year did the Colorado Rockies franchise play its first season? In what year did the Miami Marlins franchise play its first season? In what year did the Arizona Diamondbacks franchise play its first season?