Night Owls vs Early Birds

With the recent time change for some of us around the world to standard time (sorry, we are not in daylight savings time), it effects a lot of us with regards to sleep patterns.  It's almost like dealing with jetlag.  But interestingly, I do not mind this time change as we "fall back" and gain an extra hour of sleep that first day of standard time and I get to wake up at a more "normal" time relative to the sunrise.  But for others, some may wake up at 4:30am instead of 5:30am and feel rather alert, maybe annoyed.  I definitely fall under the "night owl" category waking up after the sun has risen while those that can wake up at the crack of dawn are "early birds."  

But... That leads me to question... 

Why? 

Why do we have night owls (such as myself) and why do we have early birds?  And how do these two types of people work in today's society?

If we were to remove any type of time keeping devices (clocks, sun dials, TV with set time for shows, etc.), and just go by the sun, how would that really effect us?  Was there any evolutionary advantages between night owls and early birds?

According to this website, there seems to be some advantages back when people group themselves into tribes.  Some people may stay up late to guard the village until late into the night while some would wake up early to guard the village in the wee hours of the morning.  Make sense.

But in the modern world, it seems like the "good paying jobs" are for the early birds, whether you're in the office or in construction or have to work a mechanics job that starts the shift before the shop is open.  Luckily, some office jobs do have flexible hours where night owls can start later but those companies are few and far between.  Most of us night owls have to suffer in silence while working in the early bird world.  But there are a lot of jobs at night as well with regards to healthcare, food services, and maybe writers/authors, artists, and musicians.  

There does seem to be some advantages to early birds: healthier and thinner, more positive, have a steadier sleep schedule, and can be more sociable.  Surprisingly however, night owls tend to be more intelligent, can focus more later in the day, and can be more creative.  

So, in conclusion: both of these types of people in the world came about through our evolutionary development as people interacting with other people.  What worked in our early days at humans being in tribes can still work today in our modern working world of the various occupations we have in our world.