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Lecture notes Life on Earth (GS10310)

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Extensive lecture notes and books summaries, as well as practical notes

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Vertebrate Palaeontology Notes

Chapter 1 – Vertebrates Originate

 Vertebrates = Fishes, Amphibians, Reptiles, Birds and Mammals
 Phylum = Chordata
 All chordates shared several characteristics.
o Dorsal hollow nerve cord
o Shared developmental pattern.
o Endostyle organ
o A tail used for swimming (only chordates have a true tail)



Chapter 2 = How to study vertebrate fossils

 Most people are introduced to vertebrate palaeontology at an early age when they see dinosaurs in a
movie, in a colourful book, or at a museum.



 The bones of fossil vertebrates have been collected from many sites around the world. New localities
are occasionally discovered by chance, but most excavation is now carried out in places that are already
well known for their fossils.



 If they are seeking dinosaurs, they will choose to investigate rocks dated from Late Triassic to Late
Cretaceous in age.


 They will, of course, search only in sedimentary rocks, and in rocks deposited in ancient lakes, rivers, or
deserts, for example.


 If their interest is in fossil sharks, they will usually investigate sediments laid down in ancient seas.
Large fossil bones are generally located by prospecting.


 The collector walks back and forwards over likely areas of rock that are being eroded away by water or
wind, either in ‘badland’ areas or on coasts.


 Erosion is necessary to expose fresh remains. Once the collectors find broken and disturbed pieces of
bone, usually small fragments,


 They follow them back uphill to their source.


 There may be a portion of limb bone or a rib poking out of the side of the slope. Then the collectors
must try to assess the nature and size of the specimen and how it is lying, so that they can plan the
excavation.



 Large fossil bones are generally located by prospecting. The collector walks back and forwards over
likely areas of rock that are being eroded away by water or wind, either in ‘badland’ areas or on coasts.



 Erosion is necessary to expose fresh remains.

,  Once the collectors find broken and disturbed pieces of bone, usually small fragments, they follow them
back uphill to their source.


 There may be a portion of limb bone or a rib poking out of the side of the slope. Then the collectors
must try to assess the nature and size of the specimen and how it is lying, so that they can plan the
excavation.


 Excavation of large vertebrate skeletons is a laborious and expensive process.


 Earlier collectors, such as the dinosaur and mammal bone hunters of the ‘heroic’ period, from 1880–
1910, in North America, employed hordes of labourers who extracted huge bones at incredible speed,
but with little regard for their context.


 Excavators usually take more care now. The rock overlying the skeleton, the overburden, is stripped off
using mechanical diggers, power drills, picks and hammers, or even explosives and bulldozers.


 Once a level just above the skeleton has been reached, the excavators switch to smaller power drills,
hammers, and picks.


 The skeleton is exposed from the top and the bones are cleaned up with needles and brushes and
protected with soluble hardening compounds.



 The bones must somehow be removed safely from the site.


 The excavators first isolate each bone, or group of bones, on an island of sediment around which they
dig trenches. Each block is covered with wet paper or foil, to act as a separator, and then capped with
several layers of sackcloth (burlap) soaked in plaster.


 Large blocks are strengthened with wooden beams.


 The excavators burrow underneath the plaster-capped mounds, and attempt to break through the
pedestals beneath them, but well below the bones.


 They then clear out the sediment from behind the bones, and plaster over the base. Each bone, or group
of bones, is now entirely enclosed in a plaster shell, and the blocks can be moved safely.

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