Transcript History of Life

THE HISTORY OF LIFE
• EARLY HISTORY OF
EARTH
• EVIDENCE
• HOW OLD IS
SOMETHING?
• WHAT IS
GEOLOGIC TIME?
• FIRST CELLS
• ENDOSYMBIONT
THEORY
Courtesy NASA/JPL-Caltech
http://origins.jpl.nasa.gov/habitable-planets/invest16.html
WHAT DO YOU THINK EARLY EARTH WAS LIKE?
• HOW OLD?
• 4.5 BILLION YEARS
•BIG BANG - GRAVITY CAUSES
DUST PARTICLES TO CONDENSE
•METEORS FOR MILLIONS OF
YEARS
WHAT DO YOU THINK EARLY
EARTH WAS LIKE?
•EARTH HAS TO COOL DOWN - STEAM
ESCAPES AND RAIN ALLOWS
COLLECTION OF WATER
•EARTH NOW HAS……ATMOSPHERE
OF AMMONIA, METHANE, WATER
VAPOR, CO2, AND NITROGEN
THE HISTORY OF LIFE
•EVIDENCE
WHAT EVIDENCE DO SCIENTISTS USE?
• FOSSILS!
–TRACE
–MOLD
–CAST
–AMBER
WHERE ARE FOSSILS USUALLY
FOUND?
•WHO STUDIES THESE?
•HOW DO SCIENTISTS
DETERMINE THE AGE OF
SOMETHING BILLIONS OF
YEARS OLD?
WHERE ARE FOSSILS
USUALLY FOUND?
RELATIVE DATING
RADIOMETRIC DATING
Relative Dating
THE HISTORY OF LIFE
• WHAT IS
GEOLOGIC
TIME?
• FIRST CELLS
• ENDOSYMBIONT
THEORY
GEOLOGICAL TIME
• TOO OLD FOR YEARS OR
MONTHS
• FOUR ERAS DEPENDING ON
WHICH ORGANISMS LIVED
GEOLOGICAL TIME
• PRECAMBRIAN
• PALEOZOIC
• MESOZOIC
• CENOZOIC
WHY DO WE HAVE DIFFERENT
ERA’S?
Image courtesy of the UC Museum of Paleontology Understanding Evolution: http://evolution.berkeley.edu."
PRECAMBRIAN
• WHAT DO SCIENTISTS THINK WAS
ALIVE WAY BACK THEN??
• BACTERIA
• THIS ERA LASTED FOR BILLIONS OF
YEARS UNTIL MORE LIVING
ORGANISMS EVOLVED
PALEOZOIC ERA
540 MILLION YEARS AGO!!
• NOW THE EARTH IS
GETTING LARGER LIFE!
• FIRST PART OF PALEOZOIC
IS CALLED CAMBRIAN
• PROTISTS!
• SEA PLANTS!
Dr. Thomas W. Kammer
PALEOZOIC ERA
540 MILLION YEARS AGO!!
•
•
•
•
SEA ANIMALS!
LAND PLANTS!
LAND ANIMALS!
WHAT ENDED THE PALEOZOIC
ERA??
• MASS EXTINCTION!
MESOZOIC ERA
245 MILLION YEARS AGO!!
• DINOSAURS
• REPTILES
• SMALL MAMMALS
APPEAR
• BIRDS EVOLVE
MESOZOIC ERA
245 MILLION YEARS AGO!!
• PLATE TECTONICS
• WHAT ENDED THE
MESOZOIC ERA?
• MASS EXTINCTION!
• ? METERORITE
CENOZOIC ERA
66 MILLION YEARS AGO!
• MAMMALS FLOURISH
• PRIMATES ABOUT 30
MILLION YEARS AGO
• MODERN HUMAN SPECIES –
ABOUT 200,000 YEARS AGO
THE HISTORY OF LIFE
• FIRST CELLS
• ENDOSYMBIONT
THEORY
Courtesy NASA/JPL-Caltech
http://origins.jpl.nasa.gov/habitable-planets/invest16.html
HOW WERE THE FIRST CELLS
MADE?
• DOES ANYONE KNOW FOR
SURE?
• SPONATEOUS GENERATION
VS BIOGENESIS
• FRANCESCO REDI
• LOUIS PASTEUR’S
• EXPERIMENT
http://en.wikipedia.org/wiki/Louis_Pasteur
LOUIS
PASTEUR
LP
Pasteur filled a flask
with medium, heated it
to kill all life,
and then drew out the
neck of the flask into a
long S.
LP
• This prevented
microorganisms in the air from
entering the flask
• Allowed air to flow freely. If the
swan neck was broken,
microbes could enter the flask
and grow.
• ALEXANDER OPARIN CREATION OF
MACROMOLECULES
WITHOUT OXYGEN
• STANLEY MILLER AND
HAROLD UREY EXPERIMENT
ONE CELL ORGANISMS NOW!
• FIRST BACTERIA
AROUND 3.5
BILLION YEARS
AGO
ONE CELL ORGANISMS NOW!
SOME ARE CYANOBACTERIA
- THESE ARE
PHOTOSYNTHETIC
BACTERIA - HMMMMMMM
WHAT ARE THESE BACTERIA
GOING TO PRODUCE?
•ALMOST 10% ABOUT 2.5 BILLION
YEARS AGO
•WHAT TYPE OF CELLS ARE
BACTERIA?
WHAT TYPE OF CELLS
ARE ALL OTHER
ORGANISMS?
WHERE DID EUKARYOTIC
CELLS COME FROM?
ENDOSYMBIOSIS
THE HISTORY OF LIFE
• ENDOSYMBIONT
THEORY
• Proposed by Lynn
Margulis in 1960
Courtesy NASA/JPL-Caltech
http://origins.jpl.nasa.gov/habitable-planets/invest16.html
ENDOSYMBIOSIS
BEGINNING OF THE
EUKARYOTIC CELLS
• EVIDENCE FOR
ENDOSYMBIOSIS
• DNA