Creation from single being

--- -From aitareya upanishad ऐतरेय उपनिषद 3.2

सोऽपोऽभ्यतपत्ताभ्योऽभितप्ताभ्यो मूर्तिरजायत ।
या वै सा मूर्तिरजायतान्नं वै तत् ॥

so 'po 'bhyatapat tabhyo bhitaptabhyo murtir ajayata |
ya vai sa murtir ayayatannam vai tat ||

Translation:

The Spirit brooded in might upon the waters and from the
waters brooded mightily over Form was born. Lo, all this
that was born as form, is no other than Food.

Comments:

Contemplating for some time, looking at the waters, then up from the waters came a form. Indeed, that form that was produced from the waters was to be food. He meditated upon water and then emerged various forms of chetana and achetana the sentient and non sentient beings. Here we can note one peculiar aspect of creation. Each being evolved into its own higher form or multiplied its race! This vertical expansion took place. Horizontal expansion took place from the Supreme thought force or knowledge! We come to know from various Puranas like Agni Purana, that different species emerged from Seers who were pure knowledge embodiments