Can Climate
Change Account For Dinosaur Extinction?
Summary: In line with generally accepted
theories of evolution, Dinosaur extinction is currently believed to be due to
climate change due to various causes. However this is not correct, being inconsistent
with known facts. There are only two possibilities. Either Dinosaurs evolved to
their extinction or evolved to some other phyletic lines or species with which
ancestor – descendent relationship can’t be presently demonstrated.
. So we have moved full circle from ice age to
global warming.
Dinosaur extinction was accompanied by
extinction of Ammonites (Mollusks), Mesosaurs, Plesiosaurs, and many Mammalian
groups. No theory of relationship has been advanced to explain this association
of facts. No theory has been advanced to explain as to why not the entire
global flora and fauna became extinct due to alleged climate change but only
selected groups of animals. There is evidence that birds survived extinction
events affecting Dinosaurs. Flowering plants were making their early appearance
at the time of Dinosaur extinction.
Dinosaurs first appeared about 230 million
years back and were dominant life forms on earth from 200 million years BC
(Jurassic era) to 65.5 million years BC (end of Cretaceous). Therefore
Dinosaurs had been dominant life forms on earth for 135 million years from
beginning of Jurassic era to end of Cretaceous.
Dinosaurs had been present on each and every
continent and occupied all habitats. 500 genera and 1000 species of Non-avian Dinosaurs
are known as extant species on the basis of fossil remains. Non-avian Dinosaurs
ranged in size from present day birds (e.g. Pigeon) to the size of Sauropods
i.e. 60 meters in length and several stories high. Anchiomis is the smallest
known Dinosaur with skeletal length of 35 cm and weight of 110 gms.
Dinosaurs shared several traits with birds such
as egg laying, nest building and inhabiting all available habitats.
The following excerpt from Wikipedia (http://en.wikipedia.org/wiki/Dinosaur) shows that
Dinosaur extinction was not a sudden event lasting only a few hours, days or
years. Rather it was spread over a period of at least one million years.
Possible Paleocene survivors
Non-avian dinosaur remains are
occasionally found above the Cretaceous–Paleogene
boundary. In 2001,
paleontologists Zielinski and Budahn reported the discovery of a single hadrosaur leg-bone fossil in the San Juan Basin,
New Mexico, and described it as evidence of Paleocene
dinosaurs. The formation
in which the bone was discovered has been dated to the early Paleocene epoch, approximately 64.5 million years
ago. If the bone was not re-deposited into that stratum by weathering action, it would provide
evidence that some dinosaur populations may have survived at least a half
million years into the Cenozoic Era.[135] Other evidence includes the finding of
dinosaur remains in the Hell
Creek Formation up to 1.3 meters (51 in) above (40000 years later than)
the Cretaceous–Paleogene boundary. Similar reports have come from other parts
of the world, including China.[136] Many scientists, however, dismissed the
supposed Paleocene dinosaurs as re-worked, that is, washed out of their
original locations and then re-buried in much later sediments.[137][138] However, direct dating of the bones
themselves has supported the later date, with U–Pb dating methods resulting in
a precise age of 64.8 ± 0.9 million years ago.[139] If correct, the presence of a handful of
dinosaurs in the early Paleocene would not change the underlying facts of the
extinction.[137]
Any climate change causing pan-global mass
extinction of Dinosaurs along with a few other animal groups namely, Ammonites,
Mesosaurs, Plesiosaurs and a few Mammalian groups over a period of one million
years should have, rationally speaking, resulted in near extinction of the
entire flora and fauna on earth. But to the contrary there is evidence that
birds survived extinction event. Flowering plants (Angiosperms) made their
early appearance during this period.
There are known other mass
extinction events affecting other groups of organisms, for example planktonic
forms Globigerinidae suffered mass extinction at the end of Eocene only to
reappear later (Cifelli 1969: Radiation of Cenozoic foraminifera, System.
Zool., 18, 154 – 168).
Similarly Lazarus taxons are well known which suffered extinction at
some point in time only to reappear later. One such taxon is Coelocanthus fish
which reappeared in 1938 after extinction for nearly 65 million years
(Wikipedia: search Lazarus taxons) .
From the above account, it is self-evident that no theory explaining
mass extinction of Dinosaurs due to climate change of any kind can ever be
consistent with known facts.
Therefore, only two possibilities remain, either Dinosaurs suffered
pan-global mass extinction as biologically timed out group of organisms or they
evolved into some other group of organisms with which no ancestor – descendent
relationship can be established, presently. Regarding the former possibility,
Gryphaea mollusks are known to have evolved to their extinction.
The later possibility can’t be dismissed outrightly because saltatory
evolution is known to occur. This has led to Punctuated Equilibrium Hypothesis
of Eldredge and Gould ( Eldredge N. and Gould S.J. 1972, ‘Punctuated
Equilibrium an Alternative to Phyletic Gradualism’, in Schopf T.J.M.(ed.),
Models in Paleobiology, Freeman , Cooper, San Francisco).
Darwin in 1859 in his book Origin of Species by Means of Natural
selection page 298 observed:-
That the periods during which species have been
undergoing modification though very long as measured by years, have probably
been short in comparison with the periods during which these species remained
without undergoing any change
Summing up, pan-global mass extinction of Dinosaurs could not have been
due to climatic change. It was essentially not the question of struggle for
survival and survival of the fittest or imperfect forms struggling to perfect
themselves. Therefore neither Darwinism nor Lamarckism can explain Dinosaur
extinction. There are only two possibilities. Dinosaurs either evolved to other
phyletic lines or organisms, with which no ancestor – descendent relationship
can be presently demonstrated or Dinosaurs evolved to their extinction, alternative
speaking were biologically timed out. What really happened is a matter of
further investigations.
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