From the Islamic point of view, we simply say that the universe was formed by Allah's will and according to His commands. Similarly, life began when Allah willed that it should begin. You ask about the original substance of life. If your question relates to human beings, we take what the Qur'an says about this. Human life is, then, made of the combination of the clay and the spirit.
Scientists say that human existence on earth is a recent development.
It may be so. There might have been some other creatures of men living on earth, and these could have been of a primitive variety of men. That does not contradict what I have just mentioned about the combination of clay and spirit in the making of man. We simply cannot specify a date for the beginning of human existence. Nor can we say anything about the timing when the clay was combined with the spirit by Allah's order.