"I think there are different yeasts. Ales being different from lagers for that reason."
Absolutely right, lager yeasts tend to be bottom fermenters and ale yeasts top fermenters but essentially they do the same thing...convert sugar into alcohol. You could use lager yeast to ferment an ale and vice versa. The very name 'lager' just means 'storehouse' and relates to the days when the fermented drink was stored in cellars and caves to allow it to age. Lagers also tend to be much paler due to the lightly roasted malts used.
In my opinion no one in the UK makes a drinkable lager, they just make fizzy piss. The Europeans however have had lager brewing cracked for centuries. Some of the Belgian Trappist lagers (and ales) are to die for.
Regards,
Jay.