a) Methodology

Biological sciences are characterized, historically, by a teleological tradition which permeate all their concepts of words and utilitarian notions (organs, functions, advantages) which are, in last analysis, judgments of value. The probabilistic model banishes all these concepts and postulates the need for the biological concepts neutrality.

b) Biological evolution: report and causality

The biological evolution fact collects today almost the consensus of all the researchers. The current explanatory standard model is the S.T.E. (the Synthetic Theory of the Evolution). This model explains the evolution by: 1) the genetic random mutations 2) the advantageous genetic mutations perennization by the natural selection. The S.T.E. is a finalist model that the probabilistic model integrates by interpreting it in a neutral way. The probabilistic model is presented as a post-darwinian model.

c) Living matter environment and composition

It is noted that the 9 most spread chemical elements, in mass, in %, in the living organisms composition (O2 80, H2 10, Ca 1, C 1, N2 1, P 10-1, K 10-1, S 10-1, Si 10-1) find oneself in the 9 chemical elements most widespread either in the earth's atmosphere (on 20 km), or in the earth's crust (on 15 km), or in the hydrosphere, except for phosphorus.

This convergence or this parallelism between the chemical elements presence and abundance on the ground surface and the alive beings current composition is found in many other physical factors (electromagnetic waves /vision, sonorous vibrations /hearing, etc...), chemical (calcium/endoskeletons and exoskeletons, oxygen and respiratory systems, pheromones/sens of smell, etc...) or others. One can define the whole of all these factors by the "term" environment to which organisms react.

d) A probabilistic interaction model environnement/organisms

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).

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.

The probabilistic model first application relates to the calcium biochemistry probabilistic influence and the mass extinctions.

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.

As a whole, the secondary era was a 180 M.Y. relative orogenetic and volcanic long period of calmness. An environmental and a calcareous sedimentation prevail during most of Mesozoic and particularly at the Cretaceous (as its name indicates it). With the late Cretaceous, one witnesses an orogenetic activity and the apparition of volcanicity (Dekkhan Trapps in the Indies - the Columbia River and the Snake River in the U.S.A.).

In Mesozoic many phyla and animal groups thrive, whether Vertebrates or Invertebrates, with an internal or external significant skeleton (vertebrae, rostres, tests, shells, etc...) which consisted of various compounds of calcium, calcite, aragonite, phosphates, carbonates, sulphates, etc...: marine or terrestrial Reptiles, Rudists, Ammonites, Foraminifera, Coccolithophoridae, Bivalves, Corals, etc...

The mass extinction in Maestrichtian, at the K/T limit, relates to 50 % of the kinds (38 % of the marine kinds), that is to say 65 to 70.% of the species (90 % of the planktonic species, 100 % of the marine Reptiles, Ammonites, Rudists species, etc...). 100 families are extinct.

A fine analysis of the genus percentages existing at the finish-Cretaceous which survive the K/T limit (according to Emiliani, Kraus and Shoemaker statistics 1981) makes it possible to correlate the food chain and the biomineralization processes disturbance and the organisms with more or less significant calcic metabolism. disappearance or attack.

Survivors % after limit K/T:

On 29 listed Groups:

4 whose calcic metabolism misses or minor are not or relatively not very affected: Radiolaria with siliceous skeleton - 93; Dinoflagellates with cellulose theca - 78; Elasmobranchii with cartilage skeleton - 67; Diatoms with siliceous hull - 31.

19 whose calcic metabolism is significant disappear completely or are very affected: 1) Coccolithophoridae - 13; 2) Planktonic Foraminifera - 13; 3) Ammonoids - 0; 4) Belemnoids - 0; 5) Osteichthya - 4; 6) Ichthyosauria - 0; 7) Plesiososauria - 0; 8) Corals - 20; 9) Orbitoids Foraminifera -0; 10) Hippuritids - 0; 11) Cheloniaa - 23; 12) Sauropterygia - 0; 13) Lacertilia - 27; 14) Snakes - 0; 15) Crocodilia - 12; 16) Saurischia - 0; 17) Ornitischia - 0; 18) Pterosauria - 0; 19) Birds - 0.

3 are more or less affected: Nautiloids - 50; Pelecypods - 43; Oysters - 32.

3 are saved: Amphibia - 100; Mammals - 52; Benthic Foraminifera - 75/85.

In short, on 29 groups, 26 (4 + 19 + 3) that is 90 % of the groups testify to a correlation (by their persistence, their disappearance or their small percentage of survivors) between their endoskeleton or their exoskeleton nature and importance and the trophic chain disturbance and the calcium biomineralization processes to the finish-Cretaceous. The examination of the surfaces and the periods when the Dinosaurs and the terrestrial Reptiles appeared , indicates that there is a correlation, in space and in time, between the apparition of the fossils of Dinosaurs and a preliminary or concomitant marine transgression which makes it possible to found the calcium probabilist trophic chain. The 70 Dinosaurs world fossiliferous sites knew a marine transgression concomitant or former of Trias, Jurassic or Cretaceous. A contrario, no fossiliferous site of Dinosaurs is listed without any concomitant or former marine transgression.

One notes the existence, at the K/T limit, of five factors (out of 7) probabilistic disturbers of the calcium biomineralization: 1) glaciations and temperatures fresh or cold; 2) a higher CO2 level; 3) an orogenetic and volcanic intense activity; 4) an increase in the pH acidity; 5) a food chains rupture (nannoplancton - coccolithophoridae - and microplancton extinction - Foraminifera; Angiospermae disappearance).  

Other arguments consolidate the mass extinction probabilistic model at the K/T limit, at the other models expense (meteorites impact, marine regressions, viral epidemics, etc...): former phyla acmes and radiations; mass extinction selectivity, distant animal groups acmes then simultaneous disappearances, stratigraphic arguments, duration of mass extinction, etc...

Extinction level in %:

1) Crinoids - 100; 2) Cystoids - 100; 3) Blastoids - 100; 4) Echinidea - > 50; 5) Ammonoids - 100; 6) Trilobites - 100; 7) Ostracods - > 50; 8) Brachiopods - > 75; 9) Bryozoa - 75; 10) Solitary corals - 100; 11) Fusulinids Foraminifera - 100; 12) Gastropods - seriously reached; 13) Bivalves - seriously reached.

Spongiae, with limestones or siliceous spicules, are little touched.

Thus 13 groups out of 14, that is 93 %, with significant calcic metabolism die out or are really decimated.

The biomineralization disturbing probabilistic factors at the P/T limit are 6 out of 7:

1) glaciations at the 2 poles; 2) higher CO2 level; 3) terrigenous erosion and volcanicity; 4) oceans hypersalinity; 5) anoxia in the oceans; 6) food chains rupture (Foraminifera, Corals, Bryozoa, etc... disappearance).

The organisms which are the most concerned are: Bryozoa, Brachiopods, Corals, Trilobites, Graptolithes, Echinoidea, Crinoids. 100 families are extinct.

The biomineralization disturbing probabilistic factors at the Ordovician/Silurian limit are 3 out of 7:

1) glaciations and coolings; 2) higher CO2 level; 3) terrigenous sedimentation.

The organisms which are the most concerned are: Brachiopods, Corals, Trilobites, floating Algae, Conodonts, Acritarchs, primitive fishes, Ammonoids. 100 families are extinct.

The biomineralization disturbing probabilistic factors at the late Devonian are 3 out of 7:

1) glaciations and coolings; 2) higher CO2 level; 3) intense erosion: Old Red Sandstones.

4) The mass extinction at Finish-Trias (towards - 208 M.Y.)

The organisms which are the most concerned are: Brachiopods, Ammonoids (Ceratitids), bivalvular Molluscs (Taxaodonts), Gastropods, Conodonts. 100 families are extinct.

The biomineralization disturbing probabilistic factors at the Finish-Trias limit are 2 out of 7:

1) orogeny and volcanicity; 2) transgressive water hypersalinity.

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The tropical reefs history (their acme and their disappearance) coincides with the biomineralization favorable or disturbing factors presence. Other arguments a contrario consolidate the probabilistic model. Thus, the organisms with weak calcic metabolism or not any one are not or little affected by the mass extinctions (Insects with chitinous skeleton, Arachnids, Annelida, siliceous Spongiae, etc...).

It is possible to divide the "cambrian explosion " in 4 significant periods:

1) The vendian period, former to the cambrian explosion and which announces it (565/543 M.Y.) characterized by the sudden emergence of metazoa with soft body.

2) The S.S.F. appearance (Small Shelly Fossils) characterized by many tiny composed organisms with shells, spicules and a low diversity (543/530 M.Y.).

3) Tommotian and atdabanian radiations (530/525 M.Y.) with the modern lines majority and extinct lots of descendants emergence (with hard skeleton and soft body) and their biological innovations.

4) The Burgess Shale fauna (towards 520 M.Y.) who prolongs tommotian and atdabanian radiations and the lines evolution which appeared there (with hard skeleton and soft body).

According to the probabilistic model, the "cambrian explosion" is started by two environment parameters :

1) The calcium biomineralization probabilistic favorable factors for the organisms with mineral-bearing skeletons.

2) The threshold reached by the increase of the oxygen rate in the atmosphere (PO2 P.A.L.), probably > 0,10 in Cambrian, allows the construction of organisms more or less large and more advanced than the strictly epithelial breathing animals.

The available sources resulting from the earth's crust interior (mineral water and hot water sources, oil reservoirs salted water, peat and coal), have the largest iodine contents. Then come, on average, on the decreasing scale, the seas and oceans (2,3 10-4 g %), the sedimentary rocks (10-4 to 10-5 g %), the eruptive rocks (10-5 g %), then the rainwater (10-6 g %). The marine air (1,5 10-5 g/m3) contains 12 to 13 times more iodine than the continental air (1,1 10-6 g/m3). In the same way, in the organized beings, animals and vegetables, the iodine contents are more or less significant, according to their marine or terrestrial origin, algae (10-3 g %), marine fishes (10-3 to 10-4 g %), meats (10-5 to 10-6 g %), terrestrial plants, bread, vegetables, etc... (2 10-6 g %).

Iodine, 47th body by importance order on the earth's crust (5,83 10-8 %) is concentrated in the liquid elements (seas and oceans, lakes and rivers) then the sedimentary rocks. The current content of iodine in the oceans is within a concentration that the only earth's crust scrubbing could not explain. It must come from a degazification, during geological periods, of the globe interior, the asthenosphere, similar to that which occurs still today at the volcanic eruptions time with hydriodic acid release (Vesuvius fumerolles), in the hot water sources (Boeloe in Java) and in the Rifts faults.

Iodine is essential to the brain development. The iodine influence in the cerebral tissue development at the man was highlighted by many researchs. During adulthood, the man's organism contains from 15 to 20 iodine mg of which 70 % to 80 % is in the thyroid one. The iodine influence on the brain development is well-known: high mountainous valleys congenital myxoedeme, which produces a physically dwarf and an idiot intellectually, because of the iodine water poverty, iodine deprives acting directly on the brain development or thyroid insufficiency related to a lack thyroide development. Many studies showed that iodine deficiency in the feeding is harmful with the brain growth. The iodine deficiency involves an insufficient production of thyroid hormones, essential to the brain growth and development. An article published in the New England Medicine Newspaper (March 1996) highlights that the thyroxine which crosses the mother placenta towards the foetus is necessary to the foetus brain development. In the past, other studies also showed that low thyroxine levels are present in the mentally delayed children. The health experts estimate that 100.000 cretins were born each year in the world because of iodine deficiency. The stupidity (Iodine Deficiency Disorder) results from a severe iodine deficiency during the pregnancy beginning. The iodine deficiency is the backwardness in the world most frequent cause. One estimates, that in 1997, 54 million Indians suffer from goitre, 6,6 million backwardnesses and 2,2 million stupidity, due to iodine deficiency (O.M.S. 1998).

Hominisation scenarii, i.e. a Primates line evolution, in the species Homo sapiens or the subspecies Homo sapiens sapiens, are very numerous. They are based on a certain number of characteristics which are most frequently called upon: the tools, the bipedy and the free hand, the brain volume and the various cultural activities (language, social life, labour division, mental faculties, etc...).

The probabilistic model leads us to seek if a probabilistic correlation can be established between the iodine sources and diffusion on the sphere surface and this encephalisation, simply characterized by the brain volume and its convolutions increase, their complexification, and the Hominids evolution. Our search concerns, on the one hand, the geological and prehistoric periods, on the other hand, at the present time, the subspecies Homo sapiens sapiens localization and settlement intensity. Our Hominids correlation model iode/encephalisation is not presented like a reducing model and a univocal explanation to the hominisation processes but in a probabilistic factor form, i.e. prevalent, among the possible causal factors.

The brain volume increase evolution, which almost quadrupled since approximately 4,5 B.Y., goes from 360 cc (Ardipithecus ramidus) to 1350 cc (Homo sapiens sapiens), while passing by 485 cc (Australopithecus africanus) and approximately 650 cc (Homo habilis).

We tried to find out if a statistical correlation can be established, in space and time, between the iodine sources during geological times (volcanic and fissural) and the principal following known fossiliferous sites:

1) Africa: North Africa (10), Eastern Africa (24), Chad (1), South Africa (13) - 48 sites

2) Middle East - 8 sites

3) Asia: Iraq (1), Uzbekistan (1), Iran (1), India (1), Georgia (1), Pakistan (2), Java (7), China (25) - 39 sites

On 95 sites, 88 sites either 92,6 % are under volcanic or fissural influence and 7 or 7,4 % are not it. A correlation of 92,6 %, in space and time, between the fossiliferous sites and the volcanic and fissural close zones excludes any randomly distribution and consolidates our model.

Analysis Olduvai site reveals that in the 7 fossiliferous formations, all the 216 known sites are under volcanic influence (ashes, wind or air tuffs, sediments and volcanic refuses, etc...) and when the emissions are dated, they coincide with the fossiliferous datings: Laetoli: Sandiman; lay down I: Ngorongo, Olmoti; Masek layers: Kerimasi; layers Ndutu and Naisiusiu: Oldoinyo Lengai.

The neandertalian european fossiliferous sites analysis (most of the neandertalian sites) gives the following results:

1) Sites under near volcanic influence (sources located from 0 to 100 km): 76 sites

2) Sites under possible volcanic influence (sources located at more than 100 km): 2 sites

3) Sites without proven volcanic influence: 6 sites

On 84 sites, 90 % (76/84) are under near volcanic influence

2 % (2/84) are under possible volcanic influence

8 % (6/84) are without proven volcanic influence

These percentages establish an unambiguous correlation between the localization of the sites and a near volcanic influence excluding any distribution from the fossiliferous sites with a randomly distribution. One also observes, a contrario, the almost total absence of the Hominids fossiliferous sites, until the middle Paleolithic end, in the volcanic activity deprived areas at plio-pleistocene.

The contemporary iodine sources are, on the decreasing scale: 1) the seas and oceans with an average iodine content of about 2,3 10-4 g % (the marine fishes contain from 40 to 100 times more iodine than the terrestrial origin food, vegetables, bread, meats, fruits, etc...), the marine air contains 12 to 13 times more iodine than the continental air; 2) the lakes with average contents lower than 7 10-5 g %; 3) the rivers with contents of 4 10-6 to 5 10-5 g %; 4) the sedimentary rocks, of 10-5 to 10-4 g % (that depends on the sea distance and depth). Other available sources contain more or less iodine, the volcanic activity solid or gas products, certain mineral water (6 10-2 g % in Java - Boeloe), the peat (1 to 4 10-3 g %), oil wells salted water (4 10-3 to 10-2 g %), etc...

We analyzed, according to their iodine most significant sources proximity, on the decreasing scale (seas M, volcanos V, lakes L and continents C) the ground current settlement intensity (statistics 1993/1994):

1) Agglomerations starting from 1 million inhabitants

M: 68 %)

V: 6 %) Density: 158 I/Km2

L: 3 %)

C: 23 % Density: 1,5 I/Km2

2) The world population densities

M: 51 % Density: 137 I/Km2 - M/MC: 137/91 = 1,5 times

MC: 18 % Density: 91 I/Km2 - MC/C: 91/16 = 5,5 times

C: 31 % Density: 16 I/Km2 - M/C: 137/16 = 9 times

3) An exemplary case: the United States

M: 53 % Density: 92 I/Km2 - M/MC: 92/38 = 2,5 times

MC-LC: 22 % Density: 38 I/Km2 - MC-LC/C: 38/10 = 4 times

C: 25 % Density: 10 I/Km2 - M/C: 92/10 = 9 times

These results are completely in phase with the corresponding averages figures in the world (1,5 times, 5,5 times and 9 times).

4) The insular settlement

9 % of the world population for 1,50 % of the surface - Density 238 I/Km2

5) The lowest densities

3,80 % of the world population for 40 % of the surface - Density 4 I/KM2

6) The strongest densities

7) Conclusions

If we summarize the results obtained in these various searchs, we note that they show a correlation without ambiguity between the iodine current vectors proximity and the ground settlement densities intensity, with increasing densities ranging (I/Km2), from 4 (lower super-continental densities), to 16 (continental), 91 (maritime-continental), 137 (maritime), 238 (islanders) and 287 (stronger insular, maritime, lake and volcanic densities).

After calcium and iodine, a third probabilistic interaction application between the environmental evolution and the biological evolution is proposed. It relates to the molecular oxygen rate evolution free in the earth's atmosphere during ages, which can also be regarded as a stimulus to which the organisms, its origin and its consequences react.

The crust/ocean/atmosphere system enrichment in free PO2 P.A.L. intervened, mainly, according to photochemical reactions grouped under the photosynthesis generic term and, marginally, of the water vapor photolysis. This process is, currently, and primarily, the plants fact. One considers the oxygen molecular free current percentage at 5 % of the present total oxygen at the earth's crust surface.

The most significant stages go from:

Hadean-Protorezoic (4,6 to 2,5 B.Y.) PO2 P.A.L. from 0 to 0,005

2 B.Y.: PO2 P.A.L. = > 0,01

Vendian (565 M.Y.) PO2 P.A.L. = > 0,07

Cambrian (544 M.Y.) PO2 P.A.L. = > 0,10

Devonian (408 M.Y.) PO2 P.A.L. from 0,65 to 0,74

Cenozoic (65 M.Y.) PO2 P.A.L. 1

According to the probabilistic model, the PO2 P.A.L. rate evolution in the atmosphere, from the Archaean to our days, is a prevalent parameter, probabilistic, of the living organisms evolution, from procaryotes to the " superior " Vertebrates. In a concomitant way with the PO2 P.A.L rate increase, one expects the emergence of organisms to the increasingly significant needs for oxygen:

3,85 to 2 B.Y.: PO2 P.A.L. from 0 to 0,01 - procaryotic cells

1,9 to 1,5 B.Y.: PO2 P.A.L. > 0,01 - aerobic eucaryote cells

565 to 544 M.Y.(Vendian): PO2 P.A.L. > 0,07 = < 0,10 - dipoblastic and tripoblastic metazoa

544 to 505 M.Y(Cambrian): PO2 P.A.L. > 0,10 - cutaneous and branchial watery breathing

438 to 408 M.Y.(Silurian): PO2 P.A.L. > 0,13 - Pulmonary and trachean apparatuses first appearance at the Vertebrates and the Invertebrates. Invertebrates first fossils with air breathing, Arachnida (oldest known, a trigonotarbide gone back to 414 M.Y. with pulmonary respiration), marine scorpions (higher Silurian Palaeophonus), myriapoda. Exoskeletons and endoskeletons secretion, swim bladder acquisition at Actinopterygii (higher Silurian) which will become a lung at Dipnoi in Devonian.

408 to 360 M.Y. (Devonian): PO2 P.A.L. from 0,65 to 0,74 - Simultaneous diversification of the various modes air, cutaneous, pulmonary, trachean, mixed breathing. "Explosion", starting from Devonian, of air breathing in the Metazoa groups majority and particularly at the Gastropoda and the Vertebrates. Air breathing develops at the same time on ground and in the aquatic environments.

360 M.Y. to Actuel: PO2 P.A.L. 1 - Pulmonary and trachean respiratory possibilities blooming at the Vertebrates (Reptiles, Mammals, Birds) and the Invertebrates (Molluscs: terrestrial pulmonata gastropods, Insects, etc...).

This biological probabilistic evolution under the PO2 P.A.L. rate increase influence passes by a certain decisive number of stages, conditioned by what one can indicate under the threshold term, which are the minima from which the organisms or the biological systems respiratory have the possibility of appearing.

PO2 P.A.L. = > 0,01 - 2 B.Y. - 0,01 PO2 P.A.L. threshold for the protists aerobic breathing - emergence towards 1,9 B.Y. of the oldest known aerobic eucaryote cells (Gryptania spiralis).

PO2 P.A.L. > 0,07 = < 0,10 - 565 - 544 M.Y. (Vendian): Metazoa with soft body production threshold which requires, for the collagen, muscles production and the cutaneous respiration (marine worm Dickinsonia), a minimum of 0,07 PO2 P.A.L.

PO2 P.A.L. = > 0,10 - 544 to 505 M.Y.(Cambrian): Cutaneous and branchial watery breathing and many biological innovations threshold, coelomic circulation, hemal or blood circulatory apparatus, respiratory pigments, calcium phosphate and/or carbonate exoskeleton biomineralization and secretion threshold.

PO2 P.A.L. > 0,13 - 438 to 408 M.Y.(Silurian) - PO2 P.A.L. 0,65 to 0,74 - 408 to 360 M.Y. (Devonian): Air breathing threshold (atmospheric gas oxygen absorption and either only dissolved in water) with the increase in PO2 P.A.L. in Silurian. Pulmonary and trachean apparatuses first appearance at the Vertebrates and the Invertebrates. In Devonian, with a PO2 P.A.L. rate carried to 0,65/0,74, the various modes of air, cutaneous, pulmonary, trachean, mixed breathing simultaneous diversification, become possible.

PO2 P.A.L 0,93 - 360 to 295 M.Y. (Carboniferous): Trachean and pulmonary respiratory possibilities blooming.

PO2 P.A.L. 1 - 295 M.Y.- Current (Permian, Mesozoic, Cenozoic): Complete current air respiratory possibilities.

The respiratory systems development chronology, aerobic, watery (cutaneous and branchial) then air (cutaneous, trachean and pulmonary) among protists (eucaryote cells) then the metazoa (vendian fauna, Vertebrates and Invertebrates with air breathing) cannot be regarded as fortuitous. It is parallel and concomitant with the PO2 P.A.L. evolution. It concerns, simultaneously, the taxa existing majority. One can thus consider, rightly, that the emergence common denominator of the various respiratory systems is the PO2 P.A.L. rate. Maybe, probably, around 0,01 for the aerobic eucaryote cells breathing, approximately 0,07 for cutaneous watery breathing, from 0,10 to 0,16 for branchial breathing and probably towards 0,67 for air breathing.

The optimization Principle globalise, by means of the Bernoulli law of great figures, in the biological field, the economy principles which govern the general physical phenomena (the shortest movement, minimal energy, less action). The optimization Principle thus appears, in last analysis, like the biological synthetic expression of the probability theory, applied to the biological processes.

The S.T.E. (Synthetic Theory of the Evolution) constitutes, today, the standard model for the evolution explanation. The probabilistic model is not opposed to the T.S.E. and with its assets: genetic mutations, mutations rate, genetics of the populations, population cages experiments, etc... It integrates the S.T.E. while interpreting, in a different way, the relations between organisms and environment. According to the S.T.E.., the permanent interaction between the random genetic variations and the natural selection, which sorts the favorable variations, ensures the organisms to the medium adaptation. According to the probabilistic model, the permanent interaction between the organisms and a fluctuating environment, direct the genetic mutations. This interaction, not finalist, of probabilistic and optimal nature, ensure the organisms adaptation to their environment. The S.T.E. thus interprets the population cages experiments results like the most suited survival (value judgment). The probabilistic model integrates these facts, by interpreting them in a different way, objective, like the probability theory resultant. The individuals, or the species, whose survival mathematical chances are largest, by their robustness, or all other factor, is those which survive. Thus, fecondity like any other advantage, is not interpreted any more, in the probabilistic model, as an advantage which perennializes the individual or the species, but like an increase in the survival mathematical chances. Individuals, or species, whose survival mathematical chances are weaker (more fragile, more vulnerable, less fertile, etc...), are eliminated. It is the simple application, in these experiments, of the great numbers law. Like einsteinian relativity absorbed the newtonian gravitation, the probabilistic model integrates the S.T.E. genetic variations and their prolongations, mutations rate, genetics of the populations... by directing them and in substituing to a finalist logic, the natural selection, a neutral logic, probabilistic and optimizing.

To conclude, it is significant to recall that the probability theory use is a constant in many natural phenomena study and modelisation. Let us quote, just to be reminded of it, statistical mechanics, thermodynamics (in particular its second law), the gases kinetic theory, quantum physics, Mendel laws in genetics, etc...