V
CONCLUSIONS
The probabilistic model proposes that the
biomineralization and the calcium food chain probabilistic disturbing factors
are the most probable causes of the mass extinctions and in particular of the
disappearance of the dinosaurs.
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...
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...).
A few words
about chance. The probability concept is opposed to the determinism concept
(Laplace 1814) which refers to a strict causality whereas, in the probability,
the causal relation is looser and the foreseeability statistical. The
statistical probability has, nevertheless, nothing in common run with the
chance which is pure contingency, unpredictability and which one can define as
the two independent causal series meeting (Cournot 1843). Thus, in the mass
extinction at the KT limit, the meteoric shock assumption (Alvarez 1980) arises
from the pure contingency and is the result, a priori unforeseeable, of two
independent trajectories meeting, those of the earth and a meteorite. In the
probabilistic model, the phenomenon is interpreted by the calcium stimulus
probabilistic influence on the organisms (Vertebrates and Invertebrates), which
appears at the same time by the organisms acme and disappearance with
significant calcic metabolism, the extinctions selectivity, the Dinosaurs
radiation and extinction (with its paleogeographic locations), etc...
All these facts
are unexplainable in the models based on chance, which take into account only
the extinctions, without their selectivity, and ignore completely the former
radiation phenomena.
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