Growth model of the reared sea urchin Paracentrotus ... - SciViews

General conclusions
models obviously belong to a more general family where metabolic time tM
is a function of time t as well as several other environmental
(meta)variables [von Bertal. with tM = f(t, xi…)].
There are perhaps other unidentified sub-groups. The Weibull model is
a generalization of von Bertalanffy 1 with an exponent applied to time t.
As such, it could belong to both the dimensional and the metabolic time
sub-groups. We do not see any functional meaning of them, but it could
exist. A generalized logisitic model was proposed by Nelder (1961) and
Turner et al (1969). It is a logistic function where an additional parameter
m is applied as a global exponent. From its analytic form, it is a
dimensional model, which makes sense only when it is applied to
individual growth. Turner (1969) indicates that, when applied to
populations, this model accounts for growth with a maximum population
size that is allowed to vary. It this context, it may belong to another
unidentified sub-group.
The generalized von Bertalanffy with tM (eq. 42, p. 175) is at the
same time a 'dimensional', a 'transitional' and a 'metabolic time' model. It
represents the highest level of generalization in the "von Bertalanffy 1"
family but it spans a large space for deriving other kinds of models.
Finally, there are some unclassifiable models, such as Gompertz,
Johnson, Jolicoeur and Tanaka. Either they are purely descriptive
models that just mimic the shape of some functional models, or their
affinity is not established yet. In the first case, they have clearly no place
in the proposed functional classification, as it is the case for other purely
descriptive models (e.g., Rao's polynomial growth model; Rao, 1965;
Basu, 1999). In the other case, a reparameterization or a good example of a
functional use is probably required to reveal their real nature.
Much space is left empty in this typology for adding new functional
models when growth of other animals and plants will be described in a
functional way. Such a classification should help choosing the right growth
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