Missing altogether?

I’m sure there are many, many species that haven’t been discovered yet. But as for no trace of them, they’d have to have lived in a very isolated area and/or have no skeleton for there to have been no fossils of them at all.

Jellyfishes the size of whales once populated the seas.

This is a very interesting question, I would love to hear how the “Scitentites” 11 explain that. There could have been scores of ephemeral small animals or insects never recorded fossil wise, or stuck in amber etc. If all saved samples of butterflies, etc were destroyed in a short time today because of a nuclear war or something and then somehow the sites of the cities were excavated by beings who knew nothing of the war. How would they ever knew that moths, butterflies, etc ever existed here? No one was around back then, the only thing that says anything was the artifacts, the fossils, bones, or any creature who were unlucky to get itself caught in a bog, tar pit, flow of amber, etc. Even the color, skin texture, etc, is all speculation based of today’s creatures. In reality it could be miles from today’s creatures in spite of similar bone or skeletal configuration. IMO there is a lot missing because it wasn’t robust enough to survive. The picture me may have might only be 5 chapters of a book of 16, but most scientist tries to say we have every chapter but one or a half of one.

@Hypocrisy_Central – If humanity were wiped out today, the plates of earth’s crust would shift and bury all signs of our existence fairly quickly (in geologic time). There would be so sign that we ever existed. Perhaps equipment on the moon and Mars might survive geologic time, and any aliens who found them might be able to guess our general body shape from chairs and such, but would tell them very little else about us.

Largely missing from the fossil record are not just soft-bodied creatures, but also the soft tissues of animals that do leave fossil remains of skeletons and teeth. Fossilization is a rare event requiring extremely unusual conditions, & fossilization of soft parts (e.g., Burgess shale) is even rarer. Most living things leave no trace after death. Without a doubt there are many unknown extinct species that never left fossils, or whose fossil remains are yet to be discovered.

The fossil record is best regarded as a series of snapshots taken at irregular intervals over the eons, and it is biased in favor of organisms that are fossilizable. Early life, when organisms had fewer hard parts, remains very elusive indeed. The origin of life itself (abiogenesis) is a largely theoretical discipline for lack of evidence. Molecules don’t leave fossils.

Speaking of the Burgess shale: The book to read is Wonderful Life by Stephen Jay Gould.

@HungryGuy There would be so sign that we ever existed. For humans there more than likely would be. We have machines, buildings, our bones are more robust than many small animals. But insects and such without bones to be left, could vanish without a trace if all record of them did not survive. The only way they would ever be known to exist if any samples of them survived in a lab, on a flashdrive, a microfish, etc. short of that, there would be no bones to survive to be found later.