Quoting Bhagawad Gita 2.22
वासांसि जीर्णानि यथा विहाय नवानि गृह्णाति नरोऽपराणि। तथा शरीराणि विहाय जीर्णा न्यन्यानि संयाति नवानि देही।।2.22।।
"As a person sheds worn-out garments and wears new ones, likewise, at the time of death, the soul casts off its worn-out body and enters a new one."
Does this mean that the total population has to remain constant? Or it continuously decreases as some atmas attain moksha? Is this satisfied by the provision of inter-species transfer of atma considering total biomass remains roughly the same? Is there also a provision of creation of new atma entities?