to historian Will Durant, medical research was set back several
decades because scientists refused to accept basic evidence for human
blood circulation. Until very recently in historical terms, most
scientists believed disease spontaneously arises. Two decades into
the 20th Century, the majority still believed in an eternal static
universe containing a single Milky Way galaxy.
Since the mapping of the human genome and other recent evidence, today there are major revisions taking place in biology, astronomy, physics, quantum mechanics, and virtually every other field imaginable. Many if not most scientists today believe life existed prior to the earth itself.
Emerging theory among various astrobiologists goes something like this: What causes life came out of the big bang, is refined in stars, is constantly re-seeded from supernovas and other cosmic events, finds it way around accretion disks of newly formed stars, and, from there, ends up on innumerable planets and space-rock debris.
Additionally, many geneticists have begun to openly challenge fundamental natural-selection theory, contending that reproductive survival is only one of several reasons why living forms change. How to define "species" is still debated; the term itself is a human construct, part of an invented system artificially classifying life according to our very limited view and understanding of a much larger cosmic process.
The modern evidence is overwhelming that all of life is created to adapt and change within an ever-changing grand-design cosmic reality, very far over our collective heads. And, though what we define as "species" arise and die out, life itself marches on, in spite of great cataclysmic events here on earth and, much larger and far more destructive events within a space/time continuum called "universe".
On the other hand, today there is zero evidence life ever has or ever will "evolve", in the sense life somehow magically self-designed from scratch. According to the Encyclopedia Britannica article "Evolution", modern science doesn't know how, when, where, or why life first arose on earth, or what form it took. Life adapts and changes in reaction to ever-changing universal environments, and that is all.
For all we know, life may have existed prior to the universe we live in. And, life may continue to exist forever and ever, long after our current universe passes away. Does science really know what is true? You decide.