ORIGINS OF LIFE EARLY IDEAS I SPONTANEOUS GENERATION

ORIGINS OF LIFE

EARLY IDEAS I. SPONTANEOUS GENERATION: (NOT REJECTED UNTIL THE MID 1800 S) -LIFE ARISES FROM NON LIVING MATERIAL -FRANCESCO REDI, AN ITALIAN SCIENTIST, IN 1668 TESTED THE IDEA THAT FLIES AROSE SPONTANEOUSLY FROM ROTTING MEAT. (SCIENTIFIC COMMUNITY NOT ALL CONVINCED)

EARLY IDEAS II. THEORY OF BIOGENESIS: • LIVING THINGS CAN ONLY PRODUCE LIVING THINGS • LOUIS PASTEUR DESIGNED AN EXPERIMENT TO SHOW THAT BIOGENESIS WAS TRUE EVEN FOR MICROORGANISMS

MODERN IDEAS: MILLER-UREY EXPERIMENT SIMPLE MOLECULE FORMATION: • 1943 STANLEY MILLER AND HAROLD UREY: MILLER-UREY EXPERIMENT ADD THE PICTURE TO YOUR NOTES AND LIST THE STEPS IN THEIR EXPERIMENT (WATCH VIDEO)MILLER UREY

MODERN IDEAS: MILLER-UREY EXPERIMENT PURPOSE: DEMONSTRATE THE FORMATION OF SIMPLE ORGANIC MOLECULES FROM INORGANIC COMPOUNDS RESULTS: EXPERIMENT PRODUCED SEVERAL AMINO ACIDS-SUGGESTED THAT EARLY EARTH HAD SUBSTANCES THAT COULD PRODUCE ORGANIC COMPOUNDS AND THEN LIVING THINGS.

MODERN IDEAS • ONCE AMINO ACIDS WERE FORMED, PROTEINS ARE NEEDED FOR LIFE-SCIENTISTS THINK CLAY PARTICLES COULD HOLD AA TOGETHER TO FORM PROTEINS • EARLY GENETIC MATERIAL-RNA • SCIENTISTS ARE WORKING TO DISCOVER HOW ORGANIC MOLECULES BECAME CELLS

CELLULAR EVOLUTION • FIRST CELLS WERE PROBABLY PROKARYOTIC • ARCHAEA (MODERN PROKARYOTES) ARE PROBABLY THE CLOSEST RELATIVES OF MODERN CELLS • CYANOBACTERIA-PRIMITIVE PROKARYOTES-AUTOTROPHSPRODUCED OXYGEN TO FORM OZONE LAYER-ALTERS CONDITIONS ON EARTH FOR EUKARYOTIC CELLS TO SURVIVE AMOEBA SISTERS ENDOSYMBIONT THEORY

ENDOSYMBIONT THEORY • 1966, LYNN MARGULIS, ANCESTORS OF EUKARYOTIC CELLS LIVED IN ASSOCIATION WITH PROKARYOTIC CELLS-POSSIBLY INSIDE-DEVELOPED MUTUALLY BENEFICIAL SYMBIOTIC RELATIONSHIP • EVIDENCE: • MITOCHONDRIA AND CHLOROPLASTS HAVE THEIR OWN DNA AND RIBOSOMES SIMILAR TO PROKARYOTIC RIBOSOMES • MITOCHONDRIA AND CHLOROPLASTS REPRODUCE BY FISSION (LIKE PROKARYOTIC CELLS) VIEW: ENDOSYMBIONT THEORY-CONCEPTS IN MOTION

ENDOSYMBIONT THEORY