species of life. Even the biologist and the anthropologist cannot calculate this accurately, but from authoritative, revealed scripture we get this information. Human beings represent 400,000 species, and there are 8,000,000 other species. But Krsna, the Supreme Lord, claims that all of them, whether beast, man, snake, god, semi-god, demigod—anything whatever—all of them are, in reality, His sons.
The father gives the seed, and the mother receives the seed. The body is then formed, according to the mother's body. And when the body is completely formed, it comes out—either from cats, from dogs, or from man. That is the process of generation. The father gives the seed, and it is emulsified with two kinds of secretion in the womb of the mother, and on the first night the body is formed just like a pea. Then, gradually, it develops. There are nine holes that develop: two ears, two eyes, nostrils, a mouth, a navel, a penis, and an anus.
According to his last  karma , or action, one gets this body to enjoy, or to suffer. That is the process of birth and death. And after finishing this life, again one dies, and again one enters into the womb of some mother. Another type of body then comes out. This is the process of reincarnation.
We should be very diligent as to how we can discontinue this process of repeated birth and death and change of body. That is the prerogative of the human form of life. We can stop this process of repeated change through birth and death. We can get our actual spiritual form again and be blissful, full of knowledge and eternal life. That is the purpose of evolution. We should not miss this. The entire process of liberation begins just as we have now begun this chanting and hearing. I wish to point out that this chanting of the holy name of God (HARE KRSNA, HARE KRSNA, KRSNA KRSNA, HARE HARE/ HARE RAMA, HARE RAMA, RAMA RAMA, HARE HARE) and hearing the truths of the  Gita  is as good as bodily association with Krsna. That is stated in the  Gita . This process is called  kirtan . Even if one does not understand the language, still, just by hearing, he acquires some piety. His assets lead him to a pious life, even if he does not understand—it has such power.
There are two topics concerning Krsna. Two kinds of topics, actually. One topic is this  Bhagavad-gita . It is spoken by Krsna. And the other topic concerning Krsna is  Srimad-Bhagavatam . That is spoken about Krsna. So there are two types of Krsna  katha  (topics), and both of them are equally potent because they are connected with Krsna.