III

 

THE PROBABILISTIC MODEL

 

French version

 

A biological evolution probabilistic model is proposed, based on the probability theory and the Bernoulli law of great figures. The probability theory can be summarily summarized as follows: the events whose probability and chances (mathematical) are weak, do not produce and vice versa for those whose probability and chances (mathematical) are high (monkeys typists example of Borel).

The probabilistic model proposes that current constitution of the living organisms is the most probable interaction result, statistically, between the environment stimuli and the living matter specific properties. The environment having evolved since the Precambrian one, the living organisms evolution would be also the most probable result of the interaction.

One application of the probabilistic model relates to the calcium biochemistry probabilistic influence and the mass extinctions and the causes of the disappearance of the Dinosaurs.

The cycle carbonate-silicate allows the calcium ions release which intervene in certain biomineralization processes. These processes, located at the organic chemistry and biology limit, allow to the exoskeletons or endoskeletons and the calcium current marine food chain construction, the base of which is the planktonic unicellular algae trinity: coccolithophoridae (nannoplancton with calcareous exoskeleton), diatoms (with siliceous walls) and dinoflagellates (with organic walls).

The calcium, located at the 3rd rank, by abundance order, in the earth's crust, is also the third in the living matter chemical components. The constitution, by many animals, of a support significant apparatus, involves a calcium accumulation in the organism. In the human being, 99 % of calcium are concentrated in the skeleton and the teeth. Calcium plays an essential role in the exoskeleton or the endoskeleton of many Invertebrates and Vertebrates, Protists and Metazoa phyla. Calcium can be regarded as a probabilistic stimulus to which react the organisms by the skeletons development. The variations, during geological periods, of the influence in the environment of this stimulus, involve, according to our model, in a probabilistic way, an evolution either morphological (increase in the skeleton importance at the Dinosaurs and Rudists), or towards radiations (Ammonoids), or towards the extinctions (Dinosaurs, Crinoids, etc...).

The 5 more significant well-known mass extinctions are the extinctions at the Ordovician/Silurian time, late Devonian, Permian/Trias and Cretaceous/Tertiary limits, the most significant one being at the P/T limit, the most well-known one at the K/T limit.

The probabilistic model proposes that the biomineralization and the calcium food chain probabilistic disturbing factors are the most probable causes of the mass extinctions.

The most probable factors favorable to the calcium biomineralization (dependent or independent):

1) supersaturated calcium++ ions

2) temperature (hot or tropical)

3) low CO2 level

4) orogenetic and volcanic calmness

5) neutral or alkaline pH

6) favorable O2 level

7) intact food chain.

The most probable disturbing factors of calcium biomineralization (dependent or independent):

1) under-saturated calcium ++ ions

2) glaciations, fresh or cold temperatures

3) higher CO2 level

4) active orogeny and volcanicity

5) acid pH

6) anoxia

7) food chain breakage.

 

Next : IV The evidences of the probabilistic model

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