Transcript Tasmanian Tiger

"If most of us are ashamed of shabby clothes and shoddy furniture,
let us be more ashamed of shabby ideas and shoddy philosophies...
It would be a sad situation if the wrapper were better than the meat
wrapped inside it."
Albert Einstein
What does it mean for an organism to be
extinct?
What does it mean for an organism to be
extinct?
It existed some time in the past, but has no
surviving members.
Can you name any organisms that have
become extinct?
Can you name any organisms that have
become extinct?
Carolina Parakeet
Passenger Pigeon
Neanderthal Man
Mammoth
Saber Toothed Tiger
Dinosaurs
Tasmanian Tiger
What does it mean to be endangered?
What does it mean to be endangered?
Species that may become extinct because
their population is small.
Extinction is the process of natural selection.
It occurs when a species does not adapt to
changes in the environment fast enough.
Changes in the environment include habitat
change and habitat destruction
CAROLINA PARAKEET
Tasmanian Tiger
Passenger Pigeon
Mammoths
IT IS OFTEN DIFFICULT TO
TELL FROM THE FOSSIL
RECORD WHEN MASS
EXTINCTIONS HAVE
OCCURRED.
THE FOSSIL RECORD IS
NOT COMPLETE.
ORGANISMS HAVE TO DIE
IN CERTAIN
CIRCUMSTANCES TO END
UP AS FOSSILS.
SCIENTISTS GENERALLY AGREE THAT THERE HAVE
BEEN 6 MAJOR EXTINCTIONS IN GEOLOGIC TIME.
Late Cambrian
Late Ordovician
Late Devonian
End Permian - GREATEST MASS EXTINCTION
Late Triassic
End Cretaceous - KT EXTINCTION - THE END OF
DINOSAURS
THE LATE CAMBRIAN EXTINCTION
LIFE REALLY TOOK OFF IN THE CAMBRIAN. THERE
WAS A GREAT DIVERSITY OF LIFE IN THE SEAS AT
THAT TIME.
AT THE END OF THE CAMBRIAN, THERE WAS A
MASSIVE DIE-OFF. THE REASONS ARE NOT
ENTIRELY CLEAR, AS MANY OF THE ORGANISMS
HAD SOFT BODIES AND DID NOT LEAVE MANY
FOSSILS.
IT IS SUSPECTED THAT THE EXTINCTIONS WERE
THE RESULT OF A CHANGE IN SEA LEVEL THAT
CHANGED THE ENVIRONMENT OF THESE MARINE
CREATURES.
THE LATE ORDOVICIAN EXTINCTION
THIS EXTINCTION OCCURRED ABOUT 440 MILLION
YEARS AGO.
THE CAUSE IS THOUGHT TO HAVE BEEN AN ICE
AGE THAT RESULTED IN TYING UP MUCH OF THE
WATER IN ICE SHEETS.
MANY SPECIES LOST UP TO 50% OF THEIR
MEMBERS.
SCIENTISTS THINK THAT THIS EXTINCTION
OCCURRED IN TWO PHASES.
THE LATE DEVONIAN EXTINCTION
THIS EXTINCTION TOOK PLACE ABOUT 365 MILLION
YEARS AGO.
SCIENTISTS THINK IT OCCURRED OVER A PERIOD OF
ABOUT 3 MILLION YEARS.
ABOUT 70% OF ALL SPECIES VANISHED.
SCIENTISTS ARE NOT IN AGREEMENT WITH THE
REASONS, BUT MANY THINK IT HAD TO DO WITH
CLIMATE CHANGE, AS MANY OF THE SPECIES LOST
WERE WARM WATER SPECIES.
THE END PERMIAN EXTINCTION
ABOUT 245 MILLION YEARS AGO, THE LARGEST
EXTINCTION TO EVER OCCUR HAPPENED.
AS MANY AS 96% OF ALL MARINE SPECIES AND 3/4
OF ALL LAND SPECIES WERE LOST.
SEVERAL CAUSES HAVE BEEN PROPOSED,
INCLUDING SEA LEVEL CHANGE, VOLCANIC
ACTIVITY, AND AN ASTEROID COLLISION.
THE MOST IMPORTANT FACTOR SEEMS TO BE
CILMATE CHANGE.
POSSIBLE REASONS FOR PERMIAN
EXTINCTION:
-IMPACT
-VOLCANISM
-FORMATION OF A SUPER CONTINENT
-CLIMATE CHANGE
-GLACIATION
-OTHER
GORGONOPSIA
A CYANOGANTHUS A MEMBER OF
THE THERAPSIDA - MAMMAL LIKE
REPTILES
THE LATE TRIASSIC EXTINCTION
THIS IS ONE OF THE LESS SIGNIFICANT
EXTINCTIONS.
ABOUT ONE QUARTER OF ALL SPECIES
DISSAPEARED ABOUT 208 MILLION YEARS AGO.
THE VACANT NICHES WERE FILLED BY THE
DINOSAURS.
AT LEAST TWO EXTINCTIONS WERE INVOLVED.
CLIMATE CHANGE SEEMS TO HAVE BEEN THE
MAJOR FACTOR.
THE END CRETACEOUS EXTINCTION
THIS IS ALSO KNOWN AS THE K/T EXTINCTION.
ABOUT 85% OF ALL SPECIES DISAPPEARED, IN
PARTICULAR THE DINOSAURS.
SOME SPECIES INCLUDING CROCODILES,
TURTLES, LIZARDS, MAMMALS, AND BIRDS
MADE IT THROUGH WITH LITTLE EFFECT.
METEOR IMPACT SEEMS TO BE THE MOST
PROBABLE CAUSE.
SOME OF THE THEORIES OF MASS EXTINCTIONS
ARE:
ASTEROID IMPACT
VOLCANIC ACTIVITY
CLIMATE CHANGE
SEA LEVEL CHANGE
COSMIC RADIATION AND CANCER
NICKEL POISONING
EGG EATING MAMMALS
AT THE END OF THE LAST ICE AGE AROUND 11,000
YEARS AGO, 2/3 OF ALL LARGE MAMMALS
DISSAPEARED FROM NORTH AMERICA.
WAS THIS A NATURAL OCCURRENCE OR DID WE
EAT THEM?
THOUGHTS ON EVOLUTION AND EXTINCTION
99.9% OF ALL SPECIES THAT HAVE EVER LIVED
ARE NOW EXTINCT.
THE POSITION OF AN ORGANISM ON AN
EVOLUTIONARY TREE DOES NOT INDICATE ITS
INFERIORITY OR SUPERIORITY. IT SIMPLY
INDICATES THAT ORGANISM WAS ADAPTED TO
THE ENVIRONMENT THAT EXISTED AT THAT
TIME.
MANY SCIENTISTS ARGUE THAT WE HAVE A
MASS EXTINCTION UNDERWAY RIGHT NOW.
WE ARE LOSING SPECIES VERY RAPIDLY DUE TO
HABITAT DESTRUCTION AND CHANGE.
THE AVERAGE RATE OF EXTINCTION FOR ALL
SPECIES IS BETWEEN 10 AND 100 PER YEAR.
FROM RAINFOREST DESTRUCTION ALONE, WE
ARE LOSING ABOUT 27,000 SPECIES A YEAR.
FOR MAMMALS, THE SPECIES LIFETIME IS
ABOUT 1 MILLION YEARS. SOME HAVE
SURVIVED AS LONG AS 10 MILLION YEARS.
THERE ARE ABOUT 5,000 KNOWN SPECIES
OF MAMMALS.
THE AVERAGE SPECIES LOSS IS ONE EVERY
200 YEARS.
WE HAVE LOST 89 IN THE PAST 400 YEARS
AND 169 ARE LISTED AS CRITICALLY
ENDANGERED.
I =
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X
A
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HUMAN IMPACT POPULATION AFFLUENCE
T
TECHNOLOGY
AT THE END OF THE LAST ICE AGE, WE ENTERED THE
HOLOCENE EPOCH (11,500 YEARS AGO).
PAUL CRUTZEN, A NOBEL PRIZE WINNER, HAS PROPOSED
THAT WE SHOULD NAME A NEW EPOCH, STARTING IN THE
MID 1800’S, THE ANTHROPOCENE (THE AGE OF HUMANS).
IN 1800, ONLY 3% OF THE GLOBAL POPULATION LIVED IN
CITIES.
TODAY, IT IS 50% AND RISING.
ON THE UPSIDE, CITIES USE LESS ENERGY PER CAPITA
AND POLLUTE LESS PER CAPITA THAN RURAL AREAS.