Transcript Mass Extinction Of Marine Life Cretaceous Period

By Katy Paterson and Nicole Emslie
65 million years ago, during the Cretaceous Period this is what
the earth would have looked like.
Compare that to what our earth currently
looks like. Can you spot the differences?
Plesiosauria
Elasmasaurus
Plesiosaurs
Kronosaurus
Pliosaurs
Tylosaurus
Belemnities
Monosaurus
Eventually all these marine organisms became extinct.
However some other organisms managed to survive.
For example:
There were seventeen species of turtles in the late cretaceous
period and fifteen of those species managed to survive the mass
extinction of that time.
In addition, one hundred percent of amphibians, consisting of seven
species of salamander and one species of frog, survived.
Crocodiles also survived which has puzzled many palaeontologists
because they can’t understand how crocodiles were unaffected in
complete contrast to the dinosaurs which greatly suffered.
However, the most popular theory is that a
meteorite hit the earth but it is not known
whether it was pieces of a single asteroid or
debris from a comet. The impact would
have caused lots of dust to be thrown up
into the atmosphere and would have
blocked out the sunlight. This meant that
plants were unable to photosynthesise so
died out which affected organisms in the
food chain and extinction followed.
 One theory is that there was a
series of volcanic basalt
eruptions which caused a drop
in sea level and drastic change
in climate.
Due to extreme hunting of organisms such as whales, dolphins, porpoises,
sharks, turtles, fish and seals, to meet consumer demands these organisms
are greatly decreasing in number and at one stage dolphins and whales in
particular were very close to extinction.
Other factors contributing to the decline in
numbers of populations of marine species are:
Pollution (Domestic, industrial and agricultural)
Over-fishing - especially TUNA as it is currently the
most endangered species.
http://www.youtube.com/watch?v=RDz8gg
dp_qA
Hawksbill Turtle
Steller Sea Lion
Gulf Of California Harbour
Porpoise (Vaquita)
Hammerhead Shark
Blue Whale
You may recognise some of these marine organisms in this final clip!
LISTEN TO SEBASTIAN (the lobster)
http://www.youtube.com/watch?v=C8OB
lq_svBY