If after death, the souls are transfered from one body to another, how is the population of the world increasing?

Easy definition: The biodiversity of the world comprises of the living beings of all different species.

As a human decends, or more commonly saying, dies, his soul is supposed to transfer to some other body. But this is not defined in any scientific or even humanistic concept that a human soul will always reside into a human body. Infact, there is no human soul, what exist as souls are just entities of life, be it in any form, humans, animals, plants, or any other entity that is alive, or can be alive.

So till now, we know that the population is increasing because the souls of other animals are transfered to human bodies. But here we have another question. Why isn't the population of the world decreasing? Why INCREASING is the actual question. Another approach which some might find inaaustical but, let's just put it like this. In simplest of words, it is easier for animals and plants to be born as human, than humans to be born as animals/plants. So, the population of the world is increasing because of the transfer of souls from animals to humans. Most of us are humans, but some among us are animals from their previous birth.

Which actually is so true?!

The increasing hatred around, all this voilence, crime, inhumanity, and all the other things that are not a fit for human, or let's say is inhuman, is just because it literally is! As already defined in the Hindu mythologies, during the Satya Yuga, it was almost impossible for an animal to be born as a human. And if it happens in any case, it was the result of some boon given by a Maharishi or Shiva, given to that animal because of his good deeds. But today, as Karma degrades, more and more animals are becoming human, and the human population is increasing.