Abstract 07

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Abstract 07
Old Recapitulation of Phylogeny in Ontogeny is
Still Alive, It got New Explanation in Complex
Network Area
 Andrzej Gecow
Haeckels recapitulation of phylogeny in ontogeny
has been taken dead in contemporary biology since
1977 due to the lack of its explanation.
Biologists were waiting for a long time for any
explanation of it since the fall down of the
first explanation proposed by Haeckel
inheritance of acquired characters, destroyed by
genetics. Depriving recapitulation of the first
explanation was taken as undermining of
statistical estimations which lay in the
background of recapitulation formulation. Such
estimations are hard to prove and stay
subjective, therefore they are hard to defend. In
the effect, false view has been established that
recapitulation cannot be in harmony with genetics
and it must be reconstructed to e.g.
repetitions. The main postulate of genetics is
that changes should appear evenly in whole
ontogeny, not only in the end as the
recapitulation needs. De Beer uses such an
assumption in his pure and - from contemporary
point of view naive model, where ontogeny is
only a chain of transformations and adaptive
condition describing Darwinian evolution is not
used. This model explains terminal modifications
regularity and repetition, it is old and long
time not discussed but still the latest and up
till now in force. The same main postulate of
genetics is used in our model but we consider the
ontogeny as complex network of conditional
transformations randomly evolving under adaptive
condition. This is enough to obtain statistical
effects named the structural tendencies,
equivalent of terminal modifications and terminal
addition regularities. Terminal additions
tendency is especially important, because it
creates recapitulation and lack of knowledge of
its creating mechanism was the cause of death of
recapitulation. Models form of this tendency is
the terminal predominance of addition over
removal. It is accomplished by tendency of
simplifying of deeper part of evolving system,
which means predominance of removing over
addition in the earlier area but this tendency
does not create the recapitulation it only
makes results of simulation alike Weismanns
pressing back conception. We use a wide range
of network parameters and types in the simulation
experiments. There are Kauffman networks and
similar, random Erdos-Rényi networks and nowadays
popular, scale-free Barabási-Albert networks and
others. These tendencies are present in all of
them. We also observe similarity of functional
and historical order in our simulations, it is
the main element of recapitulation idea. Computer
simulation is the powerful tool, which allows to
investigate mechanisms of these tendencies in
detail, therefore now they are known and
recapitulation can come back to biology fully
alive. Reanimation of Haeckels recapitulation
removes one of the biggest blockade in the
biology. Since the loss of its first explanation
whole discipline - comparative embryology lost
the main evolutionary aspect. To reanimate the
union of developmental and evolutionary biology,
Wilkins has distanced himself from Haeckel in
public, now he does not have do it any more. Now
recapitulation effects are expected in
conditional, complex specification characteristic
of all vertebrates and a few invertebrates.
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Old Recapitulation of Phylogeny in Ontogeny is
Still Alive, It got New Explanation in Complex
Network Area
Evolutionary biology concepts and Knowledge
This investigation is partially founded by Polish
Government
Andrzej Gecow Institute of Paleobiology Polish
Academy of Science, Warsaw Poland,
gecow_at_twarda.pan.pl
11th Evolutionary Biology Meeting at Marseilles
2007
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Recapitulation of phylogeny in ontogeny
Biogenetic law ( Haeckel 1866)
It is now negated ...
Phenotype
Parallelism of 3 ( Haeckel 1905)
Phylogeny in the sense sequence of
adult forms
???
Mutations
ontogeny stages (time in days)
embryo with gill
fish
Fossils
Ontogeny
One cell ancestor
geological time
zygote
4
Parallelism exists or not?
Phylogeny Ontogeny
Alternatives
1. recapitulations ontogenetic stages are
similar to adult ancestors 2. repetitions
similarities in ontogeny are its stage relics
only
The choice depends on mechanism of ontogeny
changes

• Haeckel suggests inheritance of acquired
  characters but genetics...
• It gives Terminal Additions regularity. (
  Pressing back conception
• Terminal Additions and
  Compression of early stages. Weismann 1902),
• - ontogeny expands by additions of new
  adaptive transformations at its end.

Lack of a mechanism. Observations must agree with
genetics!

• 2.Change initiation occurs with equal probability
  in all length of ontogeny,
• but it causes changes in all later parts of
  ontogeny.
• 
  (de Beer 1940)
• It explains Terminal Modifications and
• Conservation of early stages regularity. (Naef
  1917)
• ontogeny change types include additions and
  removals similarly,
• ontogeny changes occur more frequently near the
  end of ontogeny.

ontogeny time change initiations
repetitions
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After
0. Lack of a recapitulation mechanism. Only
repetitions remain.
1. Observations are statistical (indicated by
Haeckel) a. and subjective. They must agree
with genetics! gt recapitulation does
not exist! gt Terminal Modifications is
better and replaces false Terminal Additions
gt They are difficult to defend. Defence
will be suicide. Comparative
embryology seems to confirm recapitulation then
it is dangerous.
b. but the understanding of recapitulation is
erroneous too exact. Such a recapitulation
has lots of departures. gt recapitulation
does not exist! gt disappointment with the
value of Biogenetic Law (e.g. De Beer)
2. Gould sees recapitulation in data, he risks
(1977) to save it using heterochronies but he
loses and recapitulation dies.
3. Haeckel makes problems for us, we dont like
him! Wilkins (2002) to reanimate comparative
embryology declares better that Haeckel never
existed but he dedicates a book to Schmalhausen
...
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recalls of Darwin
Schmalhausen
Recapitulations are observed more frequently in
more complex ontogeny or organogeny .
Changes in early stages of ontogeny cause larger
phenotype changes and are typically lethal.
It explains Terminal Modifications better than
de Beer, but not the Recapitulation.
As programmer I know why and where complex
programs grow. This is the lacking mechanism of
Terminal Additions and in effect of
Recapitulation.
The first attempt to publish the model Fifth
International Congress of Biomathematics Paris
1975
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like geometrical figures,
Networks, have some properties which are
independent of their application
sah/2
h
a
Mathematical graph theory describes networks
structure, but the science of networks, which can
be complex and can function, has just developed.
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like geometrical figures,
Networks, have some properties which are
independent of their application
sah/2
h
a
The main assumption
For me ontogeny (especially conditional
specification characteristic of vertebrates) is a
complex network of conditional transformations of
structures growing randomly under adaptive
condition (Darwinian elimination).
Ontogeny for de Beer (1940) Severcov (1934)
Schmalhauzen (1942).
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Model is designed in 3 steps
Each property has s equally probable variants
(1-ideal rest equally wrong). Fitness b is a
number of identical variants of properties in
result and in requirements. Adaptive condition a
bt1 bt (Darwinian mechanism - fitness should
not decrease).
requirements result (properties)
Step 1 - we neglect source of the result.
Damage propagation Complexity threshold
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The main result of simulation Weismanns
Pressing back
output
stage of growth
terminal
late
network
We obtain all 3 elements of Weismanns conception
of Pressing back which summarizes observations
leading to Haeckels Biogenetic law.
early
Probable node migration in structure
real theoretical as was drawn
if only , only in D0
structural measure of
D - Depth
input
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Why balance of accepted - is not zero
in different places and totally ?
1. There are different sets of possibilities to
draw -.
Set of possibilities for is very large, we
must draw ? at least two nodes (or links) in
the network to indicate the place ? function for
node. a. We can always add a new node between
network and outputs and increase the
fitness (fitness b is never at its maximum
value). . b. We can always
add a transparent node anywhere (b constant)
(it does not change network function in its
current state). We reject this possibility in
part of simulations using cost i.e. a
bt1 gt bt for and a bt1 bt for -. - Set
of possibilities for is small, we can only draw
a node from the present nodes in the current
network.
Set of possibilities for is very large,
but - for
is small. 2. Reorganization of conditions for
adaptive condition test depends on number of
accepted changes in given period and area.
Part of tested possibilities in similar
conditions for is always very small
negligible but - for is significant and the
same possibilities may be tested few times. In
network areas with different modification tempo
(Terminal modifications P(aD)) P(a,D) and
P(a-,D) should differ.
Summarizing Additions and removals have very
different conditions of drawing and testing by
adaptive conditions
which depend on place in the
network. Why does anybody expect identical
effects of such different mechanisms? Total
growth of a network is also an effect of
these
differences and adaptive condition.
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Parallelism exists or not?
Phylogeny Ontogeny
Alternatives (xor)
1. recapitulations ontogenetic stages are
similar to adult ancestors 2. repetitions
similarities in ontogeny are its stage relics
only
The choice depends on mechanism of ontogeny
changes

• Haeckel suggests inheritance of acquired
  characters but genetics...
• It gives Terminal Additions regularity. (
  Pressing back conception
• Terminal Additions and
  Compression of early stages. Weismann 1902),
• - ontogeny expands by additions of new
  adaptive transformations at its end.

Lack of a mechanism. Observations must agree with
genetics!

• 2.Change initiation occurs with equal probability
  in all length of ontogeny,
• but it causes changes in all later parts of
  ontogeny.
• (de Beers
  mechanism 1940)
• It explains Terminal Modifications and
• Conservation of early stages regularity. (Naef
  1917)
• ontogeny change types include additions and
  removals similarly,
• ontogeny changes occur more frequently near the
  end of ontogeny.

ontogeny time change initiations
repetitions
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Parallelism exists or not?
Phylogeny Ontogeny
- Yes. We should expect it in nature.
Alternatives (or)
1. recapitulations ontogenetic stages are
similar to adult ancestors 2. repetitions
similarities in ontogeny are its stage relics
(later)
Common assumption (as recapitulation
opposition) Change occurs with equal probability
in all length of complex ontogeny, change types
include additions and removals similarly, but
Darwinian elimination accepts more ...
1. ... additions than removals near the end of
ontogeny, Terminal Additions ... removals
than additions far from the end of ontogeny.
Compression of early stages
Gecows mechanism
Weismann
(1902) Mechanism of Terminal Additions needs
Terminal Modifications. It creates Recapitulation
and Biogenetic Law which exist in theory.
2. ... changes near the end of ontogeny,
Terminal Modifications than far
from the end of ontogeny. Conservation of
early stages Darwins mechanism
Naef (1917)
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Tendency of Terminal
Modification and Conservation of Deeper Parts of
Network
deep fade out on k1,0
Tendencies of Terminal Predominance of Additions
and Simplification of Deeper Parts
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Similarity of functional D and historical H orders
Similarity of functional D and historical H orders
(connections to the network)
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Thanks for your attention.
Ontogeny is a complex network of conditional
transformations randomly evolving under
adaptive condition. This is sufficient to expect
Weismanns Terminal Additions and
Haeckels
Recapitulation.
Viva Recapitulation and Biogenetic Law!
Viva Comparative Embryology!
Viva Haeckel and Weismann!
Down with disbelief and blindness! etc.
gecow_at_twarda.pan.pl paleo.pan.pl/people/Gecow/Geco
w.htm
Gecow A. 2005. From a Fossil Problem of
Recapitulation Existence to Computer Simulation
and Answer. Neural Network World 3/2005,
189-201 Gecow A. 2007 (?) Structural Tendencies -
Effects of Adaptive Evolution of Complex
(Chaotic) Systems. Int.J.Mod.Phys.C, in press.
Gecow A. 2007 (?) Emergence of Growth,
Complexity Threshold and Structural Tendencies
During Adaptive Evolution of System. EPNACS conf.
in ECCS07 Dresden
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