Theories for the extinction of dinosaurs
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Transcript of Theories for the extinction of dinosaurs
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THEORIES FOR
THE
EXTINCTION OF
DINOSAURS
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INTRODUCTION
Disappeared around 65 million years ago.
Scientists do not know yet why they did disappear
although there are
three different THEORIES:
- Asteroid collision - Enormous eruptions
- Competence with mammals
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TWO VIEWS
Intrinsicgradualists
Platetectonics
Volcanism
Extrinsic
Asteroidscollisions
EARTH NATUREEXTRATERRESTRIAL NATURE
PaleontologistsAstronomers,
physicists..
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ASTEROID COLLISION
- A meteorite fell in the Earth
- It was 10km wide
- It contained iridium, a metal usually found in
asteroids.
- It created a 180km wide crater (Chicxulub) in the
Yucatan Peninsula, 65 million years ago.
- A layer of rubble (remains) was created in the
atmosphere, covering the Earth.
- Luis and Walter Alvarez were the first ones that
carried out some investigations all around the world.
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EFFECTS
This are the effects that
different scientists think
that happened:
Dust cloud blocked
sunlight for a year
Location where the
asteroid fell big
disasters (tsunamis,
earthquakes, volcanic
eruptions…)
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DIFFERENT OPINIONS
RTVE.es - 04.03.2010
Confirmado: un meteorito provocó la extinción de los dinosaurios
Fin de la discusión: un meteorito mató a los dinosauriosJOSÉ MANUEL NIEVES / MADRID
Día 08/02/2013 - 14.28h
Público.es Si un gran meteorito provocó la extinción de los dinosaurios, ¿por qué otras especies
sobrevivieron?
JORGE MORALES (INVESTIGADOR DEL CSIC) 17/08/2011
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ENORMOUS ERUPTIONS
Theory developed by Gerta Keller
EVIDENCES FOR THE TEHORY:
-Eruptions occured Clay rocks with iridium
-There were flood basalts Basalt rocks found in India
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ENORMOUS ERUPTIONS
CAUSES OF THE ERUPTIONS
-Poisonous gases were expelled
-Layer of dust around the Earth
-Climate change due to the greenhouse effect
PROBLEM OF THE THEORY
There were other flood basalts with no massive
extinction.
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COMPETENCE WITH MAMMALS
Extinction implies that the species that are
lost are poorly adapted to a changing set
of conditions.
-Taking into account the changing set of
conditions that may have occurred at the
end of the Cretaceous.
-Mammals and dinosaurs may have
competed for the last resources of mass
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COMPETENCE WITH MAMMALS
How were dinosaurs at that time?
-Most of the vast quantity of dinosaurs was big
and slow.
-The smallest species of dinosaurs were fitter and
more agile.
What mammals could have done at that time?
-Mammals at that time would have competed with
dinosaurs for food.
- Carnivorous mammals would have stolen and
preyed on dinosaur’s eggs.
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COMPETENCE WITH MAMMALS
Fossil record evidence:
-Depending on location and interpretation,
the fossil record seems to say different
things.
-It is unclear whether mammals and
dinosaurs experienced little competition or
if they regularly challenged each other for
limited resources.
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AND TO END
WITH THIS
PRESENTATION
…..
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