@giujohn,
Quote: I am a firm believer in the panspermia theory
"belief without evidence is a symptom of modern religion"
Many folks "believe" in pnspermia. There are whole pop TV "Science shows" that begin with this assertion and then, cleverly, present features of populations as "evidence" for this hypothesis.
Im not aware of ANY evidence that nails even a classroom discussion about panspermia.
Some scientists. like Dr Crick, had been fans of it but they always beg off the inconvenient missing evidence.
If we look at some other groups of animals that share our own adaptive radiation ,I would submit that we consider the many genera of PIGS
Suids .
Pigs are highly intelligent, mobile, adaptive, and quite fecund. (Pigs are my candidate for the remaining pinnacle species when humans wipe themselves off the planet). Pigs have a very visible trail of evolutionary evidence (much better than hominims), .
The point is, no one would entertain the possibility that pigs were "created" or "Assisted in their development" by intergalactic intersession.
Pigs have a similar "out of Africa" history with several burps and bottlenecks that mimic our own species.
SO, when you get too far into "believing" in panspermia, consider the not-so-lowly pig.
We can pretty easily track its entire history via palontology ND BY INFERENCE, USING "FOSSIL GENES" IN LIVING VARIETALS.
And besides, they are quite delicious.