Some geologists and evolutionary biologists dispute the Cambrian Explosion by claiming that it wasn’t an explosion at all. They reason that life must have emerged over eons of time stretching back into Precambrian layers many billions of years old. Unfortunately, such pronouncements fail to provide geologic or fossil evidence.
Actual Precambrian evidence is limited to perhaps worm trails (likely formed by digging from animals in the Cambrian) and microscopic organisms such as tiny sponges, algae, and cyanobacteria. 1
…the Precambrian…fossil record is poor, with the majority of fossils being stromatolites…(perhaps) some 2.5 billion years ago.”http://www.fossilmuseum.net/Paleobiology/Precambrian-Fossils.htm
Despite the missing Precambrian evidence evolutionary popularizers literally draw illustrations (see main illustration) to detail imagined genetic trees on how life must have evolved from these microscopic organisms called a deep divergence perhaps billions of years ago.
Thereby reasoning that animals such as the incredible trilobite did not “suddenly” emergence in the Cambrian but earlier “trilobite-like” forms existed much earlier in the Precambrian. Some species such as the stromatolites began diverging perhaps over a billion years ago.3 Arguing that ancient “novel” life forms like cyanobacteria existed perhaps 3.5 billion years ago.3 From these microscopic creatures all other life forms diverged. Such a theory makes sense within the perimeters of anticipated time lines and mechanisms of evolution, therefore, evidence or not, such deep divergence in the Precambrian must be true.
The only problem with this Deep Divergence theory is the evidence…or more precisely, the absence of fossil evidence.
Other related blogs: Cambrian Explosion limited to only 5 million years?, Cambrian Layers missing Transitionary Forms or Missing Links, Darwin’s Missing Fossil Evidence, Prebiotic Soup Missing in Fossil Record, and Punctuated Equilibrium Offered to Explain Missing Links in Fossil Record.
2 “Ultrastructure of compacted DNA in cyanobacteria by high-voltage cryo-electron tomography” by Murata, K., Hagiwara, S., Kimori, Y. et al. Sci Rep 6, 34934; Oct 2016 https://doi.org/10.1038/srep34934
3 “Early Archean (3.3 Billion to 3.5 Billion-Years-Ago) Microfossils from Warrawoona Group Australia” by Schopf & Packer; pg. 70