Transcript Permian Period - Geology12-7

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The Permian is a geologic period and system
characterized among land vertebrates by the
diversification of the early amniotes into the ancestral
groups of the mammals, turtles, lepidosaurs and
archosaurs. It is the last period of the Paleozoic Era and
famous for its ending epoch event the largest mass
extinction known to science. The Permian Period was
named after the kingdom of Permia in modern-day
Russia by Scottish geologist Roderick Murchison in 1841.
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During the Permian, all the Earth's major land masses
except portions of East Asia were collected into a
single supercontinent known as Pangea. Pangea
straddled the equator and extended toward the poles,
with a corresponding effect on ocean currents in the
single great ocean.
•Deserts seem to have been widespread on
Pangea. Such dry conditions favored
gymnosperms, plants with seeds enclosed in a
protective cover, over plants such as ferns that
disperse spores. The first modern trees appeared in
the Permian.
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The Cimmeria continent rifted away from Gondwana and drifted
north to Laurasia, causing the Paleo-Tethys to shrink.
A new ocean was growing on its southern end, the Tethys Ocean,
an ocean that would dominate much of the Mesozoic Era.
Three general areas are especially noted for their extensive
Permian deposits - the Ural Mountains (where Perm itself is
located), China, and the southwest of North America, where the
Permian Basin in the U.S. state of Texas is so named because it has
one of the thickest deposits of Permian rocks in the world.
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The Permian ended with the most extensive extinction
event recorded in paleontology: the Permian-Triassic
extinction event. 90% to 95% of marine species became
extinct, as well as 70% of all land organisms. It is also the
only known mass extinction of insects. On an individual
level, perhaps as many as 99.5% of separate organisms
died as a result of the event. Recovery from the
Permian-Triassic extinction event was protracted; on
land ecosystems took 30M years to recover. There is also
significant evidence that massive flood basalt eruptions
from magma output lasting thousands of years in what
is now the Siberian Traps contributed to environmental
stress leading to mass extinction.
Climate
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As the Permian opened, the Earth was still in the grip of an ice
age, so the polar regions were covered with deep layers of
ice. Glaciers continued to cover much of Gondwanaland
(one of the continents of Pangea), as they had during the
late Carboniferous. At the same time the tropics were
covered in swampy forests.
Towards the middle of the period the climate became
warmer and milder, the glaciers receded, and the
continental interiors became drier. Much of the interior of
Pangea was probably arid, with great seasonal fluctuations
(wet and dry seasons), because of the lack of the
moderating effect of nearby bodies of water. This drying
tendency continued through to the late Permian, along with
alternating warming and cooling periods.
•Coral
is a marine
organism that is made up
of millions of smaller
genetically identical
polyps
•They secrete calcium
carbonate to for a hard
exoskeleton
•Most corals depend on
sunlight therefore they
tend to grow in shallow
water and often bond
together to form reefs
•Trilobites
are hard
shelled, segmented
creatures that lived
between The Cambrian
period and survived up to
the Permian period
•Trilobites were widely
spread their fossils are
found across every
continent in the world
•Gastropods
were the
largest and the most
successful of the molluscs
classes
•They have developed
aggressive eating
mechanism and
pulmonary system
•The early Gastropods
had spiral shells that
resembled a curled
garden hose
• Belemnites
were squidlike carnivores with a soft
body around an internal,
pencil-shaped shell
• The cuttlefish is the
modern-day relative of
the belemnite
• Belemnites were efficient
carnivores that caught
small fish and marine
animals with their
tentacles, and ate them
with their beak-like jaws
• Their tentacles were
different to the modern
squid, as they had hooks
instead of suckers to grab
prey
• They were built for speed
and probably lived in
shoals and fossil evidence
shows they formed a
major part of the diet of
ichthyosaurs.
•A
mollusk, such as an
oyster or a clam, that has
a shell consisting of two
hinged valves
•Bivalves have no head.
They feed on
phytoplankton by
pumping water across the
gills and trapping food
particles that are then
moved to the mouth
•Superficially,
these
crinoids resemble plants,
what with there fronds,
stems, and roots
anchoring them to the
rocks. Yet crinoids are
animals, organisms with a
nervous system, and the
larvae are capable of
swimming freely before
metamorphosing to the
sessile form seen in this
photo.
•Brachiopods
make up
one of the major animal
types. Also known as
lamp shells, they are
sessile, two-shelled,
marine animals that
somewhat resemble
"clams" externally but are
quite different internally.
•Unlike bivalves, which
have a left shell and a
right shell, brachiopods
are always bilaterally
symmetric, although the
top and bottom shells
usually differ in shape.
• By
the Pennsylvanian
and well into the Permian,
by far the most successful
were primitive relatives of
cockroaches. Six fast legs,
two well developed
folding wings, fairly good
eyes, long, well
developed antennae
(olfactory), an
omnivorous digestive
system, a receptacle for
storing sperm, a chitin
skeleton that could
support and protect, as
well as form of gizzard
and efficient mouth parts,
gave it formidable
advantages over other
herbivorous animals.
About 90% of insects were
cockroach-like insects
AMPHIBIANS AND REPTILES
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Early Permian terrestrial faunas were
dominated by pelycosaurs and
amphibians, the middle Permian by
primitive therapsids such as the
dinocephalia, and the late Permian by
more advanced therapsids such as
gorgonopsians and dicynodonts.
Towards the very end of the Permian
the first archosaurs appeared, a group
that would give rise to the dinosaurs in
the following period. Also appearing at
the end of the Permian were the first
cynodonts, which would go on to
evolve into mammals during the
Triassic. Another group of therapsids,
the therocephalians (such as
Trochosaurus), arose in the Middle
Permian. There were no aerial
vertebrates.
Ferns and Conifers
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At the beginning of the Permian Period,
ferns and seed-ferns were the
dominant plant life. As the climate
grew drier, these simpler plants were
replaced by more complex plants,
such as conifers and ginkgoes.
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http://en.wikipedia.org/wiki/Permian/
http://www.fossilbase.org/index.php?pagei
d=beginner
http://www.abc.net.au/dinosaurs/fact_files
/sea/sealife/belemnite.htm
http://www.manandmollusc.net/advanced
_introduction/moll101gastropoda.html
http://www.trilobites.info/trilobite.htm
www.mnh.si.edu/LivingFossils/crinoid1.htm