'Oriental Religions (I believe that includes Hinduism, and Islam) state that there were 84 lakh types of creatures (8,400,000). The Sikh Guru referred to this commonly held belief when he wrote "All the supposed 8,400,000 species of life are offered sustenance by the Great Provider" [1]'
From "Sikh Religion and Science" by GS Sidhu
As you should already know, the GGS is compiled in many languages, sanskrit, hindi, etc. The reason being that people could understand something they already knew. The same concept (I believe) is used here when the Guru Jee says 84 lakh, just a number many Hindus understood. The Sikh Gurus, however, did not put a limit on the number of living species. They said "The species, their families, colors, and names are all recorded by His pen. If one tries to enumerate them, there will be no end to his calculations" [2].
The Hindu belief that there are only 8.4 million variety of organisms relies on the fact that this number stays constant. We, today, believe/know (I don't know if they've proven it yet) that is not correct. They say that 2 billion life forms have vanished from the beginning of Earth. Scientists today, put the number of life forms on Earth at about 30 million. More and more species are found all the time.
-Bhajneet
Lines from SGGS -
[1] chavaraaseeh lakh jon oupaaee rijak dheeaa sabh hoo ko thadh kaa || from http://www.sikhitothemax.com/page.asp?ShabadID=5433
[2] jeea jaath ra(n)gaa kae naav sabhanaa likhiaa vurree kalaam || eaehu laekhaa likh jaanai koe laekhaa likhiaa kaethaa hoe || from http://www.sikhitothemax.com/page.asp?ShabadID=16
