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                          - Dr. Walter J. Veith
                           Post Deluge Speciation and Redistribution

                     An extensive literature review on some of these issues was
carried out by L.J. Gibson of the Geoscience Research
Institute, and fascinating possibilities exist to account
for these phenomena. Briefly, the main potential for change
and speciation can be summarized as follows:

                          1) Breed selection from existing built-in variation:

                          Examples would be the breeding of the various breeds
of dogs, cats, domestic cattle, pigeons and poultry.
Some naturally occurring species how similar
differences in clines (gradient of change in population or
species correlated with the direction or orientation
of some environmental feature, such as a river, mountain
range, north-south transect, altitude, etc.) such as
the corn snake Elophe which differs in colour and scale
number along a cline. Seasonal variation in colour,
fur thickness, etc., are further examples.

                          2) Loss of genetic material:

                          Loss of genetic material has led to speciation. Loss
of flight is common in birds, particularly in island birds
where flight can be a distinct disadvantage as the
birds can be blown out to sea in storms and not make land
again. Often related species retain the capacity to
fly. Examples are the flightless rails (marsh hens), flightless
cormorant of the Galapagos Islands and the flightless
goose from Hawaii, loss of eyes in blind cave fish and
many cave dwelling insects.

                          In terms of the standard classification paradigm, loss
of genetic material leads to new species or genera but
not higher categories. Given our current understanding
of the way in which the genome works and how genes
are activated and deactivated, it is doubtful whether
the genetic information is really lost in these species.
Probably, it is just deactivated as the circumstances
do not require the features in question. Mechanisms must
obviously exist to deactivate even structural genes
coding for morphological features should the need arise.

                          These changes may be perceived as examples of
micro-evolution, but in real terms, they merely reflect quite
standard activities common to the genome.

                          3) Hybridization:

                          Most hybrids are not viable because of loss of
fertility, particularly in mammals. Some taxa are, however,
prone to hybridization and hybridization can lead to
viable species in some animals (for example, fish) and
plants. Hybrids of horses and zebras, leopards and
jaguars and even sheep and goats have been achieved,
although in the case of the latter cell linkages
between embryos of the two species were implanted in a
surrogate mother to achieve the hybrid.

                          4) Changes in chromosome structure and number:

                          Chromosomes are classified on the basis of the
position of the centromere (condensed region on a
chromosome where sister chromatids are attached to
each other after replication). When the centromere is in
the middle of a chromosome and the two arms are thus
of equal length, it is called a metacentric
chromosome. If the centromere is located at or near
one end of the chromosome, it is called an acrocentric
chromosome. Change sin chromosomal structure can be
detected by a special staining technique known as G
- banding.

                          Rearrangement of the chromosomes may entail changes in
the number of chromosomes, number of
chromosome arms as well as other changes produced by
translocation (movement of chromosome segment
to another location), deletions, duplications,
inversions and drastic rearrangements.

                          Sometimes, chromosomes can fuse with each other to
form much longer chromosomes or they can split at
the centromere to form two shorter chromosomes. One
such rearrangement is known as Robertsonian
rearrangement and is the result of either the fusion
of two centromere into one, or the splitting of the
centromere into two. A tandem fusion on the other hand
is a fusion of two chromosomes in which one end of
a chromosome fuses with the end or the centromere of
another chromosome.

                          Comparisons between the chromosome banding of the
chromosomes show that the information is still the
same, it is just rearranged. Moreover, the type of
rearrangements which occur in different animals are quite
group specific and one type of rearrangement doesn't
necessarily occur in another group.

                     Robertsonian Fusion

                     Robertsonian fusion changes the chromosome number, but not
the arm number. When chromosomes line up during
meiosis 1, a metacentric chromosome lines up with 2
acrocentric chromosomes. Examples are:

                     The house mouse Mus Musculis has 40 chromosomes, and a
population of mice form the Italian Alps was found to
have only 22 chromosomes. This population differs slightly
from the normal house mouse in morphology as well, and
is classified as a different species Mus poschiavanus.
Other populations have been discovered with chromosome
numbers varying between 22 and 40. The number of chromosome
arms are the same and banding studies reveal the
genes to be homologous. Obviously, in terms of their
relationship, these different species are all one group.

                     Tandem Fusion

                     Tandem fusion changes arm number and chromosome number.
Tandem fusion's have been found in some antelope
species where a sex chromosome fused with an autosome. This
is rare, and one can assume that the organisms
probably had a common forerunner. The antelope displaying
this fusion range in size from the eland (the largest of
all the antelopes) to smaller species such as the sitatange
and the bushbuck. They all share common features,
whoever, such as similar shapes of the horns and stripes on
the body which may be prominent as in the case of the
Bongo or less prominent as in the case of the eland.
Species with this type of fusion are: the eland, bongo, lesser and
greater kudu, bushbuck, sitatunge and nilgai (Indian
antelope) where the y-chromosome is fused to an autosome.

                     Tandem fusions are found in Malaysian swamp buffalo and
Asian river buffalo. A further very interesting example of
this type of fusion is also found in the Asian deer. In the
species Muntiacus muntjac, the females have only 6
chromosomes and the males have 7 chromosomes (this is the
smallest chromosome number in mammals). However,
in a different species of the group, Muntiacus reevesi,
both the males and the females have 46 chromosomes.
Banding studies show, that the same genetic material is
present in both species, the chromosomes in M. muntjac are
just fused together to form very long chromosomes. Once
again no new information is added, it is just reshuffled, thus
providing differential expressions and increased variety.
Just like many tunes can be played on the same piano, but
the music remains piano music.

                     Pericentric Inversions

                     These provide changes in arm number but not chromosome
number. The number of arms depends on the position of
the centromere. If it is located at the end, then there is
one arm and if in the middle there are two arms. The
inversion can change acrocentric chromosomes to metacentric
chromosomes. The rodent Neotoma and Peromyscus
differ by this inversion.

                     Translocation

                     Translocations can lead to reduced fertility, or in some
cases in humans Down's syndrome can occur where part of
chromosome 21 gets translocated to another autosome. In
some insects and plants that have meiotic drive, viable
offspring can be produced.

                     Paracentric Inversion

                     In this type of inversion the centromere is not included.
This inversion is relatively uncommon, but has been proposed
for some bats, hares and apes.

                     Drastic Rearrangements

                     Under certain circumstances of severe environmental stress,
drastic rearrangements can produce greater varieties
which could enhance survival. These changes can be rapid
when new adaptive zones are entered (canalization
model). Such rearrangements have been proposed for the mole
rate Spalax.

                     To sum up: The organismic genome is endowed with an
enormous capacity for variation. Under conditions of stress,
or where organism enter new adaptive zones or low selective
pressures there are even built-in mechanism for even
greater change and variation.

                     These findings are consistent with the creation model, and
the palaeontological record. After the deluge, precisely
such a situation existed. The new adaptive zone that was to
be reoccupied required extraordinary adaptive potential.
The palaeontological record reveals great variety of form
and structure of organisms in what we have classified as
post-floor deposits. The large mammals with the extremes in
variation such as the woolly mammoths and sabre-tooth
tigers are just some examples. Moreover, given this
tremendous potential for change, and the obvious relationship
between even species with totally different chromosome
numbers, a situation can be envisaged where a relatively
small number of "kinds" can account for large number of
"species" in a very short time. For those with faith in the
Biblical account of the ark, the problem of fitting the
animals into the ark would no longer seem as daunting. Not all
the antelope species had to be on board just a few
representative kinds.

                     The canids of the world illustrate this point dramatically.
Dogs and wolves of the genus canis have 78 chromosomes
while foxes have a varied number from 38-78 chromosomes.
The uniformity of chromosome number in canid dogs
can be due to free interbreeding over a wide range, whereas
foxes live in small family groups and smaller territories
so that new arrangements will persist. If the "kind" is
penned at the level of the family Canidae, then the implications
in terms of the number of animals required to produce the
present varieties are not as daunting as many fear. The
potential for change certainly exists, nevertheless, there
are certain barriers which cannot be transgressed. Genetic
manipulations have shown that this axiom is indeed true.
Geneticists have manipulated the genome of the fruit fly
Drosophila to such an extent that some believe that all
evolutionary events in the history of the earth do not exceed
the amount of manipulation to which fruit flies have ben
subjected. Nevertheless, although bizarre forms have been
created, the barrier which constitutes "fruit flies" has
never been broken. Similarly, a great deal of change from
chromosomal rearrangements has probably taken place since
creation, and the time frame can be consistent with a
short chronology. It is , therefore, possible to envisage
the changes to have taken place rapidly which led to the large
variety of species present on earth. Indeed, numerous
chromosome homologies have been identified in animals
today, and prescribed the differences between species can
often be prescribed rearrangements as in the case of
kangaroos, where Robertsonian fusions can account for much
of the variation between the different species.
Rearrangements can account for differences in insectivores,
bats, primates, marine mammals, rodents, rabbits and
hares and ungulates. (L.J. Gibson. 1986. "A creationist
view of chromosomal banding and evolution." Origins.
13:9-35)

                     Similarities between genetic linkages, do not however,
always have to reflect close relationships, they could just
reflect similarities in design based on functional
requirements. For example, genes for specific enzyme systems are
often situated on chromosomes with similar banding patterns
in different species. (Lalley, P.A. and V.A. McKusick.
1985. Report of the committee on comparative mopping.
Cytogenetics and Cell Genetics 40: 536-566)

                     Similarities can thus also be explained on the basis of
function rather than ancestry. In fact, similar linkage patterns
between cats and humans are almost as consistent as between
humans and chimpanzees. (O'Brien, S.J. and W.G.
Nash. 1982. Genetic mapping in mammals: chromosome map of
the domestic cat. Science. 216:257-265) Similarities
in chromosomes of humans and apes could also be explained
on this basis. Interestingly, the human karyotype seems
to be closest to the primitive condition, which does not
support the ancestral position of the apes. (Yunis, J.J. and O.
Prakash. 1982. The origin of man: a chromosomal pictorial
legacy. Science 215:1525-1530)

                     From a creationist viewpoint, the differences we see today
in the numerous species of the world, can largely be
attributed to rapid post-flood changes which have taken
place since organisms were redistributed over the earth.
Redistribution must have taken place from the ark along
three distribution lines.

                     A literature survey of mammalian distribution patterns
carried out by L.J. Gibson (Geoscience Research Institute)
shows that many mammalian species exhibit distribution
patterns consistent with an ark distribution. The various
continental and geographic barriers that exist today must
be considered to be post-flood phenomena. The two
elephant populations in the world today can serve as an
example. They can be considered relics of a much wider
distribution of elephants that became separated by the
deserts of North Africa and Arabia into the African and Asian
populations.

                     The distribution of mammals on earth is consistent with a
north-south distribution in Africa, and a west-east
distribution in Asia. There is also genetic evidence for
migration across the Bering strait. The antelope ground squirrel
(Spermopilus undulatus) and the American species (S.
columbianus) are chromosomally identical, but separating
them and living on both sides of the Bering strait is
another species, S. parryi, which has a different chromosome
number.

                     More difficult to explain, is the problem of endemic
families of animals. Endemic families occur largely in a few
distinct orders, the marsupials, primates and the rodents.
The fact that most of the endemic species occur in positions
further from the ark position (86% of endemic families
occur on the southern continents or on islands, which may
account for some of their strange features). During the
initial distribution from the ark, small groups that became
isolated form the main body due to geographic barriers or
other reasons, would have exhibited a high potential for
variation given the challenges of the new environments,
together with low competition rates cue to small population
sizes.

                     The unique fauna of Australia, in this regard, presents a
challenge to the scientific fraternity. The accepted paradigm
is, that the marsupial populations of Australia represent a
relic of the once primitive forerunners of placental
mammals, but none of the Australian endemic families have a
fossil record outside of the Australian realm. In other
words, the unique forms of not only the living animals but
also that of the immediate ancestors was already confined
to the Australian realm. Perhaps the answer lies elsewhere.

                     Why should a marsupial be considered primitive just because
of the way the young are born and raised. Why can it
not be considered adaptive? Placental mammals occur on
continents where seasonal migration is viable. Young are
born in the favourable season and are capable of
independent movement from an early age. This is very important to
ungulates that require stable seasonal food supplies and
have to undergo long migration between seasons. The same
can not be said for Australia. The food position is far
less predictable, migration is not an option and the unique
reproductive style might have been an early answer to the
challenges of the environment. Marsupial reproduction is
not primitive (unless the premature birth is considered
primitive). The young of marsupials receive the best protection
whilst at the same time they are less of a burden than
carrying a fetus to term as in the case of placentals. Marsupials
are reproductively more flexible and thus capable of
meeting extremes of environmental circumstances. Surely a
situation where two young, being raised simultaneously and
receiving differential treatment according to need (two
types of milk form two different mammary glands in the same
mother) must be considered adaptive rather than
primitive. Under conditions of environmental stress,
development can even be arrested. The particular challenges of
thepost-flood isolated island communities may have led to
some novel organismic types, but this can be merely one
of the wonders of the superb adaptability of organisms and
the built-in capacity of the genome to produce supply
variation when needed.

                     No model of origins can supply all the answers,
particularly if our knowledge of many biochemical and genetic
mechanisms is still so incomplete. The creationist model
does, however supply many plausible answers to some of
the many questions that plague us in terms of origins.
There will be areas where faith must supply the lack of
knowledge, but the same is true for the evolutionary
paradigm. In the final analysis, both paradigms thus require faith.
The question that everyone must ask himself is, which of
the two requires more faith?

Oryginal:
http://www.amazingdiscoveries.org/postdeluge.html
 



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