Suppose that we had a Super Hubble Space Telescope available. An optical telescope with diffraction-limited optics and enough aperture to image individual stars in distant galaxies. What fraction of the sky would be observed to be dark? 

It would certainly be more than 99%. If, hypothetically, 0% of the sky would be dark, all objects would on average heat up to about 3,000 K (estimate for the average temperature of thermal radiation from stars, taking into account average redshifts according to the so-called cosmic time–redshift relation). Given that dwarf planet Eris reaches a surface temperature of 30 K, it must be that less than 1% of the lines of sight from Eris hit a star. 

This is of course a loose upper bound, as Eris is very close to the star called Sun. In other words, the temperature of 30 K is almost entirely due to the relatively large portion of the Eridian sky being covered by the sun. 

If you go to the Wikipedia page dedicated to Olbers' paradox, you can read similar reasoning leading to the conclusion:


  "the sky is about fifty billion times darker than it would be if the
  universe were neither expanding nor too young to have reached
  equilibrium yet"


Which translates into roughly 99.999999998% of the sky being dark. Our universe is a cold and empty place.

How much of the universe is observable at visible wavelengths?
The chapter by Douglas Futuyma in 'Evolution' (Losos et al 2013, Princeton) states that natural selection can occur at the species level. Futuyma states that if natural selection occurs at the species level it does not occur at the individual level: 


  Neither gene selection nor species selection has molded the advantageous characteristics of individual organisms; rather, they have affected properties at the gene level or at the species level. 


But how does natural selection occuring at the species level not affect individuals? Surely any selective advantage of a particular species must occur among particular individuals of that species. For example, if Species A is selected because it is browner than Species B, this will be because individuals of Species A are browner than individuals of Species B. 
