How long has the "Clear Green Turtle" dish appeared on the menu, and tell me when its latest update was?
Clear Green Turtle is a name of dish; how long a dish appeared on the menu = SUBTRACT(last_appeared, first_appeared); latest update refers to latest updated_at;
SELECT T1.last_appeared - T1.first_appeared, T2.updated_at FROM Dish AS T1 INNER JOIN MenuItem AS T2 ON T1.id = T2.dish_id WHERE T1.name = 'Clear green turtle'