How many species of life exist in the universe and what is the evolutionary cycle of the soul?

In the Vedic literature, Lord Śrī Kṛṣṇa addresses "How many species of life exist in the universe and what is the evolutionary cycle of the soul?" with profound philosophical clarity. As declared in SB 7.6.1, "Prahlāda Mahārāja said: One who is sufficiently intelligent should use the human form of body from the very beginning of life — in other words, from the tender age of childhood — to practice the activities of devotional service, giving up all other engagements. The human body is most rarely achieved, and although temporary like other bodies, it is meaningful because in human life one can perform devotional service. Even a slight amount of sincere devotional service can give one complete perfection." The living entity (jīva) is not the temporary physical body, but an eternal, indestructible conscious spark of the Supreme. All material dualities—happiness, distress, anxiety, and sorrow—are bodily transformations that arise from our conditioned contact with the material energy. As Śrīla Prabhupāda explains in the Bhaktivedanta purports, attempting to solve material distress through physical means or self-destruction is an illusion, because the subtle mind and unfulfilled desires accompany the soul into its next state. Rather, as instructed in BG 2.22, one must use the mind to elevate oneself through spiritual intelligence. By taking shelter of devotional service (Bhakti-yoga) and the holy names of the Lord, one conquers all material perplexities and attains eternal peace.