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starvation. Food shortage resulted in intensive predation of those which could not escape or
hide. The comparison between Campanian and Lower Eocene crustacean burrow systems
into pelagic chalk suggest a change in the mode of breeding from a few large eggs specially
treated (K-type) to numerous tiny eggs partly cared for (transition to r-type) to compensate
their over-predation. Dinosaur and pterosaur eggs were laid in nests on open-flat land such
as estuaries, tidal-flats and shores. They and the few successfully hatched young provided
easy prey, most probably to carnivorous reptiles living in the same region. The hatched
young of marine reptiles were vulnerable to predation by other reptiles, sharks and large
fishes. Reptiles which hid their brood (e.g., crocodiles, sea-turtles), birds laying their small
eggs among plants or at sites inaccessible to non-flying organisms were not much affected
by the predatory stress. The small mammals of that time could hide in the underground and
in hidden places where they survived the predatory threat. The detected fluctuations in
seawater temperature during the Cretaceous last half million years (Li & Keller, 1998)
resulted from variations in the amount of volcaniclastic dust released into the atmosphere
by the Deccan volcanic eruptions of different intensities and duration. A thick, long-lasting
dust screen blocked the solar radiation resulting in the cooling of Earth's surface land and
ocean-water. A thin volcaniclastic screen created a 'greenhouse' effect raising the
temperature on the Earth. The associated darkening reduced the metabolism and the
activity of cold-blooded reptiles, whereby the large ones living on land could not withstand
even small predators. Darkening reduced and stopped the photosynthetic activity of the
symbiotic zooxanthellae in planktonic foraminifera and calcareous nannoplankton lowering
the oxygen content in the reduced euphotic zone as reflected by an increase in abundance of
microorganisms tolerating low-oxygen conditions (e.g., Tantawy et al., 2009). The lack of
these symbionts lowered the rate of calcium-carbonate precipitation, as attested to by
smaller test sizes (dwarfing) of the planktonic microfossils during the last 0.5 Myr before the
K-T boundary (Keller, 2008), being demonstrated in laboratory experiments on extant
planktonic foraminifera (Bé et al., 1982). The recovery of most of the Late Mesozoic life
forms during the Early Cenozoic suggests that all those organisms and plants survived
predation thanks to their capabilities as well as by retreating to restricted and protected
habitats. There they adapted to the local and changing ecological settings during a few
million years until most of them succeeded in returning to the open-large marine and
terrestrial habitats. Thereby they re-appeared in the fossil record, some in a new shape as
the result of adaptation to changing settings during a few million years of the recovery of
Earth's ecological systems. All of these seemingly new taxa took part in continuous
evolutionary lineages ranging across the K-T boundary and during the aftermath of the
biological crisis. They passed most of this period in hitherto undiscovered sites and
therefore these intermediate evolutionary stages do not appear in the fossil record. The
resulting different nomenclature of taxa between the Late Cretaceous and the Early Tertiary
was erroneously referred to the mass extinction of the Cretaceous species. The end-
Cretaceous biological crisis was actually an extreme example of natural selection caused by
the Deccan volcanic activity.
9. Acknowledgment
We thank Michail Kitin (GSI) for the technical assistance in the field and in the laboratory; to
Chana Netzer-Cohen and Nili Almog (GSI) for their graphic work.
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