According to Jainism, ‘Jeeva’ emerges from lower form of flora, that is ‘Nigod’ (a technical Jain word).
By the long journey of births, a ‘Jeevatman’ frees itself of ‘Pudgal’ (matter) by Heat of penances Tapasya and become a Siddha, the realised one, accomplished one. Out of many Siddhas only 24 can become Teerthankar, in an Kalpa (Long time duration) to teach & give knowledge to the humanity.
Heat of penances = Self control, remove all sins from life, it is called ‘Tap’ = तप, Tap creates ‘Taap’, the spiritual heat: