Not so elementary, my dear Watson!

"Ah, now I see what your point, dear Sherlock!" doctor Watson said excitedly.

Watson had learned to respect the deductive powers of his friend and learned how important is the attention the famous detective gives to the minute details many others would not even notice. 

"Life itself has this inner characteristic of evolving from simple to complex. Living things show that they are alive exactly by this growing and mutating and changing from generation to generation which inanimate objects do not have in them. The rock changes in the rock cycle but not by what is in the stone but by the external processes that lift hot magma to cool on the surface, erosion that breaks the rock physically to small pieces, water and wind that move the broken stones to layers and deposits that processes of metamorphosis or fire than further modify."

Sherlock noticed certain pride in his dear friends voice as this explained to him the fundamental difference between change in living things and in lifeless natural objects.

"Of course, life is also modified by external conditions and as Charles Darwin and his colleagues have explained, changes in the physical environment create challenges to mutating life forms and the most fitting species and variations survive the process of natural selection. The difference is in the variations that life produces as raw material for this process that we can logically understand and study."

Sherlock Holmes and Dr Watson had finished walking through the Natural History Museum hall that contained fossil evidence about the earliest life forms known on this planet and were both in deep thoughts.

"As you have taught me, dear Sherlock, the power of deductive reasoning works everywhere, here in the midst of scientific evidence and there in the streets of foggy London carefully examining the crime scene. It is important to observe everything, even the smallest details, in order to penetrate to the criminal mind and to solve the mystery of the murder or theft."

Watson concluded with a certain feeling of pride and satisfaction on the human achievement in the fields of geology and palaeontology. "So you see, Sherlock, giving enough time the earliest life forms on Earth some three billion years ago gradually became more complicated. The environment changed after the Snowball Earth allowing more complex life forms to evolve and survive in the Ediacaran period. These developments laid the biological foundations for the Cambrian explosion of life when time was ripe and the conditions had further improved with the melting of Ice Caps, rise of shallow waters ideal for the prospering of living things, burrowing of microbial mats, mild global temperature, rise in oxygen levels after exposed iron had oxidized and other such things."

"Not so elementary, my dear Watson" Sherlock answered.

Our dear doctor was a bit at loss when his friend questioned the logical deductions he had just made from the hard evidence.

"There is one most significant fact that you have underestimated" the famed detective continued while searching for his pipe.

"As we were told, Ediacaran life forms totally disappear in early Cambrian period. The biodiversity in Cambrian seas is in no direct way connected to Ediacara biota as scientists have so far not found a single reliable link in the fossil record between the two. It is as if life withered and began again in a different line of evolution."

Doctor Watson nodded and hoped that he also would have the brilliant mind of Sherlock Holmes that did not leave details undetected. For so it seems, the devil is in the details.