Relation between Atma and Parmatma

It is said that in the beginning there was just energy. That one energy, that one Divine light thought, I am alone, let me multiply into many. Eko'ham bahu syam (I am one, may I be many), and it assumed the form of Para Shakti (Mother Divine). Then from that came out three energies, i.e., Brahma, Vishnu and Mahesh. The creative impulse, the protective impulse and the transformative or destructive impulse. So three streams of energy that are called Brahma, Vishnu and Mahesh.
That is why it is said, in the beginning there was just one Omkar (the primordial sound). And the Omkar became 'Aa', 'Uu' and 'Ma'. We think 'Aa', 'Uu' and 'Ma' together made Omkar. No! Om was the beginning, and this one impulse expanded into three different impulses or devatas (deities).
So one paramathma or one divinity multiplied into many so that this diverse creation can come into play. 
All the scientists say in the beginning there was only one amoebiasis. From one amoebiasis all the species in the universe have sprung up.