>> WELCOME, EVERYONE. TO THE
12TH SESSION IN THE 22ND YEAR OF
A COURSE AT THE NATIONAL
INSTITUTES OF HEALT HEALTH IN
BETHESDA, MARYLAND. THE COURSE
IS CALLED DEMYSTIFYING MEDICINE
I'M WIN ARIAS. I'M A SENIOR
SCIENTIST EMERITUS AND WITH MY
COLLEAGUE DAN KASTNER WHO IS A
SENIOR INVESTIGATOR AND FORMER
DIRECTOR, PART OF THE HUMAN
GENOME RESEARCH INSTITUTE WE
WELCOME YOU TO THIS SESSION. LET
ME EXPLAIN. THE GENERAL PURPOSE
OF THE COURSE IS TO BRIDGE THE
EXCITING DEVELOPMENTS IN BIOLOGY
AND ENGINEERING WITH MEDICINE.
FOR THE MOST PART WE DO IT WITH
HUMAN -- DEAL WITH HUMAN
DISEASE, WHICH ARE PRESENTED
SOMETIMES THROUGH LIVE PATIENTS,
BUT ALWAYS WITH REPRESENTATIVES
OF A CLINICAL ARENA AND ALSO A
STATE OF THE ART BASIC
SCIENTIST. IT IS MUCH LIKE THE
LOGO IN THE UPPER RIGHT PART OF
THE SLIDE WHICH IS, MANY OF US
THE MOST FAMOUS BRIDGE IN THE
WORLD, THAT IS EASTERN
PAROCHIALISM, IN NEW YORK THAT'S
THE BROOKLYN BRIDGE CONNECTING
BROOKLYN AND MANHATTAN. AND
TODAY ONCE AGAIN, LIKE THE TWO
GENTLEMEN ON THE CAT WALK, WE
ARE DISCUSSING A MAJOR PROBLEM.
IN FACT, ONE MIGHT SAY IT IS THE
MAJOR PROBLEM IN ALL OF BIOLOGY.
WE ARE DISCUSSING THE QUESTIONS
LIKE THE ORIGIN OF LIFE. THE
DEVELOPMENT OF THE EUKARYOTIC
CELL AND MAYBE THESE TWO FOLKS
ARE ASKING THEMSELVES ARE THE
HUMAN SPECIES REALLY AS
IMPORTANT ON THIS EARTH AND ITS
CREATION AND DEVELOPMENT AS WE
THINK THEY ARE. ALL OF THESE
SEEMINGLY DIVERSE TOPICS ARE
GOING TO BE ADDRESSED TODAY.
OVERALL PURPOSE OF THIS COURSE
SYMBOLICALLY IS TO BRIDGE WHAT
ARE SILOS OF INFORMATION.
EXPERTISE IN DIFFERENT AREAS OF
MEDICINE AND BIOLOGY AND
ENGINEERING NORMALLY MAY NOT
COMMUNICATE MUCH WITH ONE
ANOTHER. THE GOAL IS TO CONVERT
THIS ESSENTIALLY INTO BRIDGES.
TODAY WE ARE ADDRESSING ONE OF
THE BROADER OPPORTUNITY IN
BIOLOGY AND I WILL GET TO THAT
IN A MOMENT. WE HAVE NEXT SLIDE
PLEASE. NEXT. THE CME CREDIT
45386. THERE IS THE PHONE
NUMBER, (443)541-5052. CAN
SPEAKER HAS NO FINANCIAL
RELATIONSHIP. WHEN ONE AT LEAST
WHEN I WAS A COLLEGE STUDENT
WHEN ONE THOUGHT OF GEOLOGY IT
WAS ROCKS. THE INTEREST WAS SORT
OF IN CLASSIFICATION
UNDERSTANDING SOMETHING OF THEIR
FORMATION, BUT IT BASICALLY WAS
PRETTY HARD SCIENCE IF YOU WILL
ONE OF MY PROFESSOR, MANY YEARS
AGO WAS WAY AHEAD OF THE CURVE.
THIS IS KIRTLEY MATHER PROFESSOR
UNIVERSITY OF HARVARD, THE LAWS
OF NATURE ARE NOT CHAINS WHICH
SHACKLE MANOR GODS WHICH DRIVE
HIM DOWN ANY PREDETERMINED
ALLEY. THEY ARE TOOLS WHICH
STRENGTHSEN HIS HANDS AND
INCREASE HIS EFFICIENCY. THEIR
IMPLEMENTS WHICH HAVE WAITED
LONG FOR HIS MASTER MIND TO MAKE
THEM USEFUL. IN THE MANY YEARS
SINCE KIRTLEY AND OTHERS
ADDRESSED ISSUES LIKE THIS,
THERE WAS A SEPARATION BETWEEN
GEOLOGY AND BIOLOGY. NEXT SLIDE
PLEASE. MANY LEADING BIOLOGISTS
FOR EXAMPLE, SIDNEY BRENNER,
SOMEWHAT FACETIOUSLY WROTE ONE
OF THE THINGS ABOUT CREATIVITY
IS NOT TO BE AFRAID OF SAYING
THE WRONG THING, WHICH IS TRUE.
SO WE ARE VERY PRIVILEGED TODAY
TO HAVE AS OUR SPEAKER ANDREW
KNOLL, WHO RECEIVED DEGREES IN
GEOLOGY AT LEE HIGH UNIVERSITY
AND Ph.D. AT HARVARD.
FOLLOWED WHICH HE SPENT FIVE
YEARS IN OVERLAND TEACHING ON
THE FACULTY AND IN 1982 HE
RETURNED TO HARVARD WHERE HE HAS
REMAINED. IS EMERITUS PROFESSOR
OF BIOLOGY AT EARTH AND
PLANETARY SCIENCES. AND
CURRENTLY A FISHER PROFESSOR OF
NATURAL HISTORY. HIS MAIN
ACTIVITIES HAVE BEEN TO DRAW
CONNECTIONS BETWEEN THE ORIGIN
OF LIFE AND THE ENVIRONMENTAL
HISTORY OF THE EARTH. THIS
IMPORTANT FIELD UNDERLIES AND
CREATES VERY DIFFERENT OPINIONS
AS TO THE ORIGIN OF LIFE BUT
HERE THE EMPHASIS IS ON THE
INTERACTION BETWEEN THE
ENVIRONMENT OF THE EARTH AS IT
CHANGES AND PARTICULARLY THE
ROLE OF BACTERIA, AND THEIR
RELATIONSHIP TO LIFE, TO
EVOLUTION AND TO SOME EXTENT AS
WE WILL SEE AND DISCUSS TO HUMAN
DISEASE. PROFESSOR KNOLL HAS
MANY HONORS A MEMBER OF THE
NATIONAL ACADEMY OF SCIENCE, THE
ACADEMY OF ARTS AND SCIENCES,
THE PHILOSOPHICAL SOCIETY, AND
THE ACADEMY OF MICROBIOLOGY. HE
RECEIVED THE THOMPSON AWARDS OF
NATIONAL ACADEMY OF SCIENCES AND
ONE OF HIS BOOKS, A WONDERFUL
BOOK CALLED LIFE ON A YOUNG
PLANET RECEIVED THE PHI BETA
KAPPA BOOK AWARD, HE'S RECEIVED
REWARDS FROM THE SOCIETY FOR
SEDIMENTARY GEOLOGY PALEONTOLOGY
AND GEOLOGY. AND IN 2022 HE
RECEIVED THE PRESTIGIOUS
CRAWFORD PRIZE IN GEOSCIENCES
GIVEN BY THE ROYAL SWEDISH
ACADEMY. PROFESSOR KNOLL HAS
ALSO SERVED ON THE SCIENCE TEAM
FOR THE NASA MISSION TO MARS AND
I TRUST THAT WILL IN OUR
DISCUSSION. TH THE TITLE OF HIS
TALK TODAY IS IT IS A BACTERIAL
WORLD. ANDY, THANK YOU, VERY
MUCH ON BEHALF OF ALL OF US FOR
YOUR TAKING THE TIME TO JOIN US
AND WE LOOK FORWARD TO YOUR
TALK. WELCOME.
>> THANK YOU, WIN.
FIRST LET ME
THANK WIN AND DAN KASTNER FOR
INVITING ME TO BE WITH YOU
TODAY. TO MANUFACTURE IT IS
SURPRISING TO BE SPEAKING AT
DEMYSTIFYING MEDICINE BECAUSE
I AM NEITHER A PHYSICIAN NOR
MEDICAL RESEARCHER, I DON'T HAVE
MUCH POSSIBILITY OF DEMYSTIFYING
MEDICINE FOR YOU. WHAT I DO DO
IS PRACTICE SOMETHING CALLED
GEOBIOLOGY WHICH IS AN EFFORT TO
UNDERSTAND HOW PHYSICAL AND
BIOLOGICAL PROCESSES IN CONCERTS
SHAPED THE WORLD AROUND US
TODAY. IF NOTHING ELSE THAT
WILL HELP TO DEMYSTIFY BACTERIA.
THERE IS A COMMON VIEW THESE
BACTERIA OR PESKY ORGANISMS
INTERPOLATED INTO A WORLD
LARGELY DEFINED BY PLANTS AND
ANIMAL BUS THE MAIN THING I WANT
TO GET ACROSS TODAY IS THAT
PRECISELY THE OPPOSITE IS TRUE.
I HAVE ASKED OUR FINANCIAL
DISCLOSURE SLIDE, I HAVE NOTHING
TO DISCLOSE, I DON'T DO RESEARCH
IN ANY AREA OF BIOMEDICAL
INTEREST. ALSO I THINK IT IS A
NICE THING THAT I WAS ASKED TO
PROVIDE LEARNING OBJECTIVES. AND
THE MAIN ONE IS TO SHARE MY
SENSE HOW MICROORGANISMS PROVIDE
THE FUNDAMENTAL ECOLOGICAL
CIRCUITRY OF EARTH AND THEY HAVE
DONE SO FOR MOST OF OUR PLANET'S
HISTORY. IS IN CONTRAST TO THAT,
COMPLEX MULTI-CELLULAR LIFE HAS
ONLY BEEN AROUND THE LAST 20% OF
THAT HISTORY AND HAS REALLY BEEN
INTERPOLATED INTO FUNCTIONING
ECOSYSTEMS BUILT ON MICROBIAL
METABOLISMS. SO PERHAPS THAT
MIGHT RESONATE WITH SOME OF YOU
AS YOU THINK ABOUT THE
RELATIONSHIPS BETWEEN MICROBES
AND HUMANS. WE'LL START OUT WITH
SOMETHING Y'ALL LEARNED IN HIGH
SCHOOL AND THAT IS THAT CARBON
CYCLES THROUGH THE BIOSPHERE AND
HERE IS JUST A VERY SIMPLE
CARBON CYCLE, IN WHICH WE HAVE
PHOTO SYNTHESIS ON ONE SIDE OF
THE CYCLE AND RESPIRATION ON THE
OTHER. SO PLANTS TAKE CO 2 AND
USE ELECTRONS DERIVED FROM WATER
TO REDUCE THE CO 2 TO
CARBOHYDRATES AND GIVE OFF
OXYGEN GAS AS A PRODUCT. ALL OF
US AS WE SIT HERE ARE DOING
REVERSE REACTION WHERE WE TAKE
CARBOHYDRATES AND OXYGEN AND
DERIVE ENERGY FROM THE OXIDATION
OF THE ORGANICS TO CO 2 AND THAT
GIVES OFF WATER AND BECAUSE
THESE TWO SITE OF THESE TWO
PROCESSES ARE COMPLIMENTARY THAT
RESULTS IN SOMETHING OF A CYCLE
THAT IS ALL WELL AND GOOD. BUT
NOTICE THE ROLE OF OXYGEN IN
THIS CYCLE WE GENERALLY THINK OF
THE CARBON CYCLE IN TERMS OF
CARBON BUT IT IS FUNDAMENTALLY
CYCLING OF WATER AND OXYGEN GAS
AS WELL AND THAT RAISES THE
QUESTION OF CAN WE CYCLE CARBON
IN THE ABSENCE OF OXYGEN? THAT
IS NOT JUST A SORT OF GENERAL
QUESTION BECAUSE THERE ARE
MANIMENT eMENTMENTS ARE OX
GENERAL IS ABSENT, THERE'S
OXYGEN MINERAL ZONES IN THE
OCEAN, PRETTY MUCH ALL STEAD
MEANTS, BELOW THE FEW
CENTIMETERS ARE AN OXIC, THERE'S
SWAMPS THE INSIDE OF YOUR BODIES
SO THERE'S MANY ENVIRONMENT
WHERE IS OXYGEN DOESN'T PLAY A
ROLE AND WE CAN ASK ABOUT CARBON
CYCLING IN THOSE ENVIRONMENTS.
IT TURNS OUT THERE ARE QUITE A
VARIETY OF METABOLISMS THAT ARE
NOT KNOWN IN PLANTS AND PANELS
THAT ACCOMPLISH THIS. SO WHEN
YOU SEE ON THE RIGHT THERE IS
SIMPLY A PHYLOGENY OF BACTERIA
AND THE GREEN CLADES THAT ARE
MARKED THERE ARE ALL PHOTO
SYNTHETIC SO THERE ARE SEVEN
WELL CHARACTERIZED SYNTHETIC
PLATES WITHIN BACTERIA AND JUST
A FEW MONTHS AGO AN 8TH ONE WAS
DESCRIBED, THOUGH NOT FULLY YET
CHARACTERIZED. WHAT IS
INTERESTING ABOUT THAT IS THAT
ONLY ONE OF THOSE BACTERIAL
GROUPS, THE SIGHIA KNOW BACTERIA
USES WATER AS ELECTRON PRODUCES
OXYGEN AS BY-PRODUCT. THE REST
USE ELECTRON DONORS THAT RANGE
FROM HYDROGEN GAS TO HYDROGEN
SULFIDE, THE FAIREST IRON AND
NUMBER OF OTHER THINGS AND THEY
DO NOT GIVE OFF OXYGEN.
RESPONSE. SO THERE IS A WHOLE
WORLD OF PRIMARY PRODUCTION
FUNDAMENTALLY DISTINCT FROM THE
ONE WE KNOW IN PLANTS. THE SAME
IS TRUE FOR RESERVATION. I LIKE
THIS DIAGRAM ON THE RIGHT BY MY
FRIEND KEN NIELSEN FROM A REVIEW
PAPER SOME YEARS BACK. WHAT IT
SIMPLY SHOWS IS ON THE LEFT-HAND
SIDE FUELS USED IN METABOLISM IN
THE RIGHT HAND SIDE OXIDANTS
ALONG THE ELECTRONEGATIVITY
CREATING IT AND AS KEN'S ARROWS
SHOW, THE CARTOONS IF YOU GO --
CONNECT THE FUEL WITH THE
OXIDANT IN A DIRECTION THAT GOES
DOWNHILL ON THIS DIAGRAM IT
YIELDS ENERGY AND CAN SUPPORT
METABOLISM. SO CLEARLY THE MOST
OXIDIZED OXIDANT WE CAN DEAL
WITH HERE IS OXYGEN GAS, THAT
YIELDS THE MOST ENERGY IN THE
RESPIRATION. BASICALLY ALL
EUKARYOTS RESPIRE AEROBICALLY,
WITH FEW EXCEPTIONS BUT THAT IS
WHAT THEY DO. MANY BACTERIA AND
-- DO AS WELL. ON THE OTHER HAND
IF YOU LOOK AT THAT DIAGRAM,
OXYGEN GAS IS NOT THE ONLY
OXIDANT THAT CAN METABOLIZE
ORGANIC MOLECULES. THERE IS
NITRATE, THERE IS MANGANESE AND
IRON OXIDES. SULFATE, AND THIS
IS ALMOST EXCLUSIVELY THE
PROVINCE OF BACTERIA AND ARCIA.
THERE IS ONE KNOWN IN THE OCEANS
CAPABLE OF NITRATE RESPIRATION
AND THAT NOT SURPRISINGLY USES A
PHYSIOLONGCAL PATHWAY THAT WAS
INHERITED BY LATERAL TRANSFER
FROM A NITRATE RESPIRING
BACTERIA. YOU WILL ALSO NOTICE
IN THE DIAGRAM THAT YOU CAN
CONNECT INORGANIC FUELS TO
OXIDANTS AS WELL AND THAT GIVES
RISE TO METABOLISM ONLY KNOWN IN
BACTERIA AND ARCIA WHICH IS
CHEMO SYNTHESIS. SO THERE IS A
MUCH BROADER RANGE OF
METABOLISMS AMONG MICROBES. AND
IF YOU JUST SUMMARIZE THE CARBON
CYCLE THEN WITH THIS SERIES OF
RINGS, ON THE OUTER RING IS
OXYGENIC PHOTOSYNTHESIS AND
AEROBIC RESERVATION, THE STUFF
OF PLANTS AND ANIMALS ALSO OF
ESSENTIALLY ALL PROTUS AND MANY
BACTERIA AND ARCHIA, TESTIMONY
ANTIOXIDANT RESPIRATION, THE
PROVINCE OF BACTERIA AND
ARCHAEA, AND I PUT FERMENTATION
IN THERE YES, WE ALL FOR MEANT
AS AN AUXILLARY METABOLISM BUT
FEW EUKARYOTS DO IT WELL THESE
BEING THE GREAT EXCEPTION. IF
YOU LOOK AT THE VARIOUS
METABOLIC PATHWAYS OF
FERMENTATION, THEY ARE MUCH MORE
EXTENSIVE AND DIVERSE IN
BACTERIA AND ACCHEAE THAN
EUKARYOTS. IT IS IN SOME WAYS A
BACTERIAL WORLD. IT BECOMES MORE
WHEN YOU CONSIDER ENERGY
METABOLISM IN EUKARYOTIC CELLS
INCLUDING YOUR OWN. AS MANY OF
YOU KNOW, THE MAJOR ENERGETIC
ORGANELLES IN YOUR OWN CELLS
WERE DERIVED FROM ONCE FREE
LIVING BACTERIA. SO ON THE LEFT
IS A FAIRLY RECENT MOLECULAR
PHYLOGENY OF ALPHA
PROTEOBACTERIA. THERE IS TWO
THINGS TO NOTICE IN HERE BOTH
WORTH MENTIONING. FIRST IS ALL
OF THE CLADES THAT ARE INCLUDED
IN THIS DIAGRAM ARE OF ORGANISMS
THAT ARE KNOWN ONLY BY META
GENOMIC ANALYSIS. THAT IS WE
HAVE NO IDEA WHAT THE ORGANISMS
AS ORGANISMS ARE LIVE, WE SIMPLY
KNOW THEY ARE GENOMES PLACED IN
THAT PARTICULAR POSITION IN THE
PHYLOGENY. IT IS FAIR TO SAY
UNTIL THE DAWN OF ENVIRONMENTAL
SEQUENCING, WE HAD NO IDEA OF
THE TRUE DIVERSITY OF MICROBES
IN THIS WORLD. WE ARE STILL
LEARNING ABOUT THAT DIVERSITY
BUT RATHER THAN BEING IS
SOMETHING LIKE 2000 BACTERIAL
SPECIES DESCRIBED FROM PURE
CULTURES, BY SAY 1970, WE NOW
KNOW THAT -- THE RIGHT NUMBER IS
IN THE MILLIONS. ALSO IF YOU
LOOK ON THAT DIAGRAM, THE BLUE
CLADE YOU SEE NEAR THE BASE IS
WHERE MITOCHONDRIA FIT IN. SO
THAT MITOCHONDRIA CLEARLY ARE
DERIVED FROM ONCE FREE LIVING
PROTEOBACTERIA THAT ENDED IN
SYMBIOSIS WITH A HOST AND WAS
REDUCED TO METHOD BOLLIC
SLAVERY. ON THE RIGHT WE SEE A
SIMILAR DIAGRAM FOR CHLOROPLAST.
THE MIDDLE CLADES THERE,S
DESIGNATED ARCHIPLASTINS ARE THE
PLACEMENT FOR MOLECULAR
PHYLOGENY OF CHLOROPLASTS IN RED
GREEN AND (INAUDIBLE) ALGAE,
LAND PLANTS THAT BASICALLY GREEN
ALGAE WITH A MASTERS DEGREE. AND
VERY CLEARLY THEY -- THOSE ARE
DERIVED FROM ONCE FREE LIVING
SIGHIA KNOW BACTERIA. SO --
CYANO BACK TIER Y THE BASIC
ENERGY EUKARYOTS IS
FUNDAMENTALLY BACTERIAL IN
NATURE. THAT IS THE CARBON
CYCLE. JUST A FEW WORDS ABOUT
NITROGEN AND SULFUR, TO SEE HOW
THEY FIT INTO THIS PICTURE. WE
ALL KNOW EVERY ORGANISM REQUIRES
NITROGEN, IT IS PROTEINS AND
NUCLEIC ACIDS AND NUMBER OF
OTHER MOLECULES. PRIMARY
PRODUCERS GET NITROGEN THEY NEED
FOR SYNTHESIS FROM EITHER
NITRATE OR AMMONIA AND SOILS OR
WATER. THEN IT PASSES THROUGH A
FOOD CHAIN, AS HETERO TROVE
PHOTO SYNTHESIZERS THEN GO ON
FROM THERE. THROUGH
DECOMPOSITION THEN AMMONIA IS
RETURN TODS THE ENVIRONMENT,
PROCESS CALLED (INDISCERNIBLE)
THAT IS DEACETYLATED BUT THERE'S
A NUMBER OF CHEMO SYNTHETIC
BACTERIA CALLED NITRO FIRES THAT
WILL OXIDIZE PNEUMONIA TO NIGH
TRIED AND THEN TO NITRATED.
USUALLY DONE BY TWO SEPARATE
ECOLOGICALLY CLOSELY RELATED
SPECIES. AND THEN THAT NITRATE
CAN ACTUALLY BE ASSIMILATED BY
PRIMARY PRODUCERS AS WELL BUT
AGAIN THERE IS COMPETITION IN
LOW OXYGEN ENVIRONMENT BECAUSE
THE NITRATE IS USED FOR
RESPIRATION. A PROCESS CALLED
DENITROGENATION, RETURN FROM THE
ATMOSPHERE. THERE IS A SECOND
PROCESS BACK TO AMMONIA
DISCOVERED ONLY A FEW DECADES
AGO. CALLED PANAMOM, AN AEROBIC
AMMONIA OXIDATION WHERE YOU HAVE
AMMONIA REACT WITH NITRITE
YIELDING ENERGY AND AGAIN
RETURNING NITROGEN TO THE
ATMOSPHERE AS NITROGEN GAS. AS
I JUST EXPLAINED, THIS IS A
PROCESS THAT WILL RUN OUTS OF
STEAM. BECAUSE IT IS A LEAKY
PROCESS WHICH KEEPS RETURNING
BIOAVAILABLE NITROGEN TO THE
ATMOSPHERE. THE REASON THAT
ECOSYSTEMS ARE ABLE TO BE
SUSTAINED OVER LONG PERIODS OF
TIME IS THERE IS ONE MORE
PROCESS AGAIN EXCLUSIVELY
MICROBIAL, CALLED NITROGEN
FIXATION IN WHICH MICROBES AND
ENERGETICALLY EXPENSIVE PROCESS
BUT THEY CAN REDUCE NITROGEN GAS
TO AMMONIA AND THAT IS PROBABLY
NEXT TO PHOTOSYNTHESIS THE MOST
IMPORTANT METABOLISM EVER
INVOLVED BECAUSE IT WITH
PHOTOSYNTHESIS ALLOWS ECOSYSTEMS
TO BE MAINTAIN FOR LONG
INTERVALS OF TIME. YOU MIGHT SAY
WELL ALL THESE BACTERIA BUT
DON'T SOYBEANS FIX NITROGEN,
FARMERS FIX SOYBEANS IN CROP
ROTATION. BIOAVAILABLE, THAT IS
HALF RIGHT. SOYBEANS ARE
INVOLVED IN THIS PROCESS, ROOTS
OF SOY BEAN WHAT YOU SEE ARE NO
DUALS ARE PLACES THEY HARBOR
SYMBIOTIC NITROGEN FIXING
BACTERBACTERIA. SO SOYBEANS THES
CAN'T FIX NITROGEN BETTER THAN
YOU AND I CAN. BUT WITH THESE SY
MANYMBIOTS THEY PLAY A ROLE IN
THE PROCESS. FINALLY SULFUR,
AGAIN TWO AMINO ACIDS USE IT,
THERE'S HUNDREDS OF ENZYMES THAT
HAVE SULFUR AS A CO-FACTOR, THAT
IS PRESENT IN WIDE VARIETY OF
BIOMOLECULES. ONCE AGAIN SULFUR
ENTERS THE BIOLOGICAL CYCLE BY
UPTAKE OF SULFATE FROM THE
ENVIRONMENT BY PRIMARY
PRODUCERS. IT PASSES THROUGH
FOOD GRABS AND THROUGH
DECOMPOSITION RETURNED TO THE
ENVIRONMENT AS HYDROGEN SULFIDE.
THEN MUCH OF THAT HYDROGEN
SULFIDE GOES INTO ENERGY
METABOLISM. AS AN ELECTRON DONOR
FOR PHOTO SYNTHETIC BACTERIA OR
CHEMO ATROPHIC MICROBES YIELDING
SULFATE AS A PRODUCTS AND THAT
SULFATE AGAIN WHILE IT CAN BE
ASSIMILATED BY PRIMARY
PRODUCERS, MUCH OF THE SULFATE
IS ACTUALLY USED IN RESPIRATION.
SOMETHING CALLED SULFATE
REDUCTION. IT IS ESTIMATED THAT
AS MUCH AS 50% OF ORGANIC MATTER
THAT LANDS ON THE SEA FLOOR IS
REMINERALIZED VIA SULFATE
REDUCTION. IT IS AN IMPORTANT
PROCESS. AGAIN AS IN THE NIGH
THROW GENERAL CYCLE ALL HEAVY
LIFTERS ARE BACTERIA AND
ARCHAEA. ONCE AGAIN YOU MIGHT
SAY I REMEMBER READING ABOUT
THESE INTERESTING WORM THAT LIVE
IN HYDRO THERMAL VENTS AND MID
OCEAN RIDGES THEY FEED BY SULFUR
CHEMOAUTOTROPHY, THE WORMS YOU
LOOK AT ARE REMARKABLE BECAUSE
THEY HAVE RED PAL PES AT THE
ANTERIOR END OF THE BODIES THEY
BASICALLY FARM CHEMOSYNTHETIC
SULFUR BACTERIA. SO AGAIN, THEY
ARE ONLY ABLE TO TAKE ADVANTAGE
OF THIS MICROBIAL PROCESS
THROUGH SYMBIOSIS. THEN IT GETS
EVEN MORE INTERESTING THAT IT
TURNS OUT INTIMATE BIOLOGICAL
RELATIONSHIPS BETWEEN MICROBES
AND COMPLEX MULTI-CELLULAR
ORGANISMS ARE UBIQUITOUS. IT IS
PRETTY CLEAR YOUR OWN BODY
CONTAINS MORE BACTERIAL CELLS
THAN IT DOES HUMAN CELLS.
PROBABLY SOME PEOPLE WHO ARE
LISTENING ARE ACTUALLY WORKING
ON THINGS LIKE YOUR GUT BIOME
WHICH CLEARLY AS WE LEARN IS
INTEGRAL TO OUR OWN DEVELOPMENT
TO THE IMMUNE SYSTEM AND HEALTH
ONCE AGAIN, BACTERIA ARE
FUNDAMENTAL TO ALL OF THIS. SO
LET'S SWITCH GEARS L GEARS A LIT
AND LOOK AT PERSPECTIVES ON
BIOLOGICAL WORLD. I LOVE THIS
DIAGRAM IN THE UPPER LEFT FROM
THE LAB OF RON MELOUGH FROM THE
INSTITUTE IN ISRAEL AND RON AND
COLLEAGUE AS FEW YEARS AGO TRIED
TO QUANTIFY THE BIOMASS OF
DIFFERENT KINDS OF ORGANISMS ON
THIS PLANET. WHAT YOU SEE IS
RESULTS OF THEIR LABORS, IN THIS
MOST BIOMASS IS IN THE FORM OF
PLANTS WITH BACTERIA SECOND AND
ONLY THAT LITTLE RED BOX IN THE
CORNER MUCH LESS THAN 1% OF
BIOMASS DO YOU FIND ANIMALS. IT
TURNS OUT THAT THE PLANTS CHEAT
IN THE SENSE THAT IF YOU GO
OUTSIDE AND LOOK CAREFULLY AT A
TREE OURSELF YOUR OFFICE, YOU
WILL FIND THAT MORE THAN 90% OF
THE MASS OFNA TREE IS NON-LIVING
CELLS BASICALLY WOODS. SO IF
YOU ONLY TAKE LIVING TISSUES OF
PLANTS, IN FACT BACTERIA TURN
OUT MOST ABUNDANT BIOMASS
ORGANISMS ON THE PLANET. IF YOU
LOOK AT THE DIAGRAM BELOW THAT
THAT IS UNIVERSAL PHYLOGENY. IT
SHOWS THE THREE MAJOR GROUPS OF
ORGASMS EUKARYOTS WHICH Y'ALL
KNOW BACTERIA, AS ADVERTISED IN
THE ARCHEA GROUP RECOGNIZED AS
SEPARATE FROM BACTERIA IN 1977.
THIS DIAGRAM NEEDS UPDATING IN
THE SENSE THAT RATHER THAN
SEEING EUKARYOTS AS A SISTER
GROUP TO THE ARCHAEA IT'S BECOME
INCREASINGLY CLEAR THE
EUKARYOTIC CELL ITSELF
REPRESENTS THE PRODUCT OF THE
MERGER BETWEEN ARCHEON FROM A
GROUP OF ARCHEA ONLY DISCOVERED
IN 2015,S AND BACTERIA. SO
EUKARYOTS ARE IN SOME SENSE A
COMPOUND ORGANISM. BUT THE ONE
THING, THE REASON I SHOW THIS
DIAGRAM IS TO MAKE IT CLEAR ONE
THING EVERYBODY AGREES ON THESE
KINDS OF PHYLOGENIES, THAT IS
THAT ANIMALS ARE SIMPLY ONE
DISTAL TWIG ON ONE BRANCH OF THE
TREE THE DEEP HISTORY IF IT IS
LARGELY MICROBIAL. THAT LEADS US
TO THE DIAGRAM ON THE RIGHT
WHICH IS SIMPLY A TIME AXIS OF
EARTH HISTORY. THE OLDEST
EVIDENCE WE HAVE OF ANIMALS ON
THIS PLANET IS ABOUT 575 MILLION
YEARS OLD. THE EARTH ITSELF IS
MORE THAN 4 1/2 BILLION YEARS
OLD AND SO THE QUESTION ARISES
WHAT PRECEDESSED THOSE ANIMALS
IN THEIR HISTORY. AND THE
INFERENCE FROM PHYLOGENY WOULD
BE THERE COULD BE A LONG HISTORY
OF LIFE THAT IS LARGELY
MICROBIAL. THE EMPIRICAL YES
QUESTION BECOMES CAN WE FINDS
INTRACTABLE RECORD OF THE
EARLIER MICROBIAL EVOLUTION
PRESERVED IN SEDIMENTARY ROCKS.
WHAT WE ARE LOOKING AT HERE IS A
PLACE THAT I WORK AT FOR NUMBER
OF YEARS WHEN I WAS YOUNGER AND
FITTER, THESE ARE ROCKS BETWEEN
750 AND 800 MILLION YEARS OLD.
THAT ARE NOW PROPPING ON THE
ARCTIC ISLAND HALFWAY BETWEEN
NORTHERN TIP OF NORWAY AND THE
NORTH POLE, TO GIVE YOU A SENSE
OF DIMENSIONS HERE, WE STUCK THE
EMPIRE STATE BUILDING AT THE
BASE OF THAT CLIFF ITS RAIDS OWE
TOWER OUTSIDE JUST PEEK OVER THE
TOP OF THE HILL SO IT IS A
REMARKABLY EXPOSED RECORD OF
VERY WELL PRESERVED SEDIMENTARY
ROCKS. SO THE QUESTION THEN
BECOMES, DO THESE ROCKS CONTAIN
ANY EVIDENCE OF MICROBIAL LIFE.
IF IF YOU LOOK AT THE UP PER
RIGHT HAND PICTURE, THAT IS A
LIMESTONE RELATIVE AND EWE SEE
WAIVE LAMB NATIONS WHICH IS
INTERRING BECAUSE IF YOU LOOK AT
MODERN ENVIRONMENTS AND ASK HOW
THOSE LAMB NATIONS FOR THEY FORM
AS INTERACTION BETWEEN PHYSICAL
SEDIMENTATION AND MICROBIAL BACK
TIERDEDES, SO THAT TEXTURE TELLS
US THIS EVIDENCE WAS CARPETED BY
MICROBIAL COMMUNITIES AT THE
TIME THE ROCKS FORMED. LOOK AT
THE UPPER CENTER OF THE
PHOTOGRAPH YOU WILL SEE THIS
BENDING UPWARD, SOMETHING
GEOLOGISTS CALL TP STRUCTURES
THEY FORM IN A SPECIFIC WAY,
THAT IS IN THE SUPER TIDAL ZONE
WHERE THERE IS EVAPORATION YOU
GET CALCIUM CARBONATE
PRECIPITATE IN THE WATERINGS OF
SEDIMENTS AND PRESSURE BUILDS UP
AND CAUSES THEM TO BUCKLING BUCM
THE TEXTURES OF ROCKS I CAN TELL
YOU WHERE THEY WERE DEPOSITED
AND THERE ARE MICROBIAL
COMMUNITIES THERE AT THE TIME
THEY FORM. IF YOU TAKE SOME OF
THOSE GRAY CARBONATE ROCKS AND
MAKE A SLICE UNDER MICROSCOPE
YOU SEE INTERLOCKING CARBONATE
CRYSTAL. IF YOU LOOK AT THOSE
BLACK PANCAKE LIKE STRUCTURE,
THOSE ARE NO DUALS OF SILICA --
NODULES OF SILICA QUARTERS THAT
FORM WITHIN THE SEDIMENTS SOON
AFTER THEY FORM. IF YOU TAKE
THIN SECTIONS OF THOSE ROCKS AND
LOOK AT THEM UNDER THE
MICROSCOPE, WHAT YOU WILL SEE
THE KIND OF THING IN THE PICTURE
BELOW THERE. THOSE ARE
MICROFOSSILS OF CYANO BACTERIA,
EACH CELLS FOUR MICRONS IN
DIAMETER, THAT TELLS US
SOMETHING IMPORTANT. THE SMALL
REALLY TINY BACTERIAL FOSSILS
CAN AND ARE PRESERVED IN THE
SEDIMENTARY ROCK RECORD. SOME
CONTAIN ENOUGH INFORMATION TO
TELL US SOMETHING OF BIOLOGICAL
INTEREST. SO WHAT YOU ARE
LOOKING AT HERE IS STALK FORMING
ORGANISMS. THERE IS A SINGLE
CELL IN THERE, THE CELL IS
DECAYED SO ALL YOU CAN SEE IS
JUST MICROBIAL GOO. BUT THERE
WERE SERIES OF EXTRA CELLULAR
ENVELOPES WHICH FORM A STALK IN
THE DOWNWARD DIRECTION. THOSE
CELLS CAN BE INDIVIDUALS OR AS
YOU SEE ON THE RIGHT THEY CAN
FORM CRUST US. AND WE KNOW
ENOUGH THAT WE CAN CREATE A LIFE
CYCLE FOR THIS ORGANISM THAT
LIVES ON THE ORDER OF 750 TO 800
MILLION YEARS AGO. IT TURNS OUT
IF YOU GO TO THE BAHAMAS TODAY
YOU CAN FIND PHYSICAL
ENVIRONMENTS THAT ARE VERY
SIMILAR TO THOSE INFERED FROM
THE ROCKS WHICH THOSE FOSSILS
WERE FOUND. WHEN YOU GO THERE,
YOU WILL FIND THESE BLACK CRUSTS
ON THE TO IT TIDAL FLAT SURFACE
IF YOU LOOK IF THE BLACK CRUST
THEY ARE MADE OF YANO BACTERIAL
CELLS, SINGLE CELLS BUT WITH
THESE ENVELOPES THAT GO FOR
STALKS SO WHAT WE HAVE IS
SEPARATED BY NEARLY 800 MILLION
YEARS FOSSIL AND LIVING
BACTERIAL POPULATIONS THAT ARE
ALMOST IDENTICAL IN TERMS OF NOT
ONLY ENVIRONMENTAL PREFERENCE
BUT MORPHOLOGY AND LIFE CYCLE.
IN FACT IF YOU LOOK IN DIFFERENT
ENVIRONMENTS BY DIFFERENT
SEDIMENTARY ROCKS IN THIS
SUCCESSION WE FINE A VARIETY OF
THINGS THAT ARE CYANO BACTERIA
BUT ALSO EUKARYOTIC CELLS. THE
VASE SHAPED STRUCTURE IN THE
UPPER CENTER IS ABOUT 100 MIC
MICRONS LONG. THAT IS A TESTMENT
ON THE LEFT YOU ARE LOOKING AT A
SMALL PIECE OF GREEN ALGA, THE
THING BOTTOM CENTER IS ABOUT
HALF A MILLIMETER ACROSS. IT HAS
A CYST INSIDE SO CLEARLY
EUKARYOTIC THOUGH WE CAN'T PIN
IT TO A GROUP. SO WHAT WE ARE
SEEING IS THE FOSSIL RECORD IS
SHOWING US THAT YES, THERE IS
EVIDENCE OF LIFE WELL BEFORE
EARLIEST ANIMALS THAT WE SEE.
THERE IS A MUCH MORE CONSPICUOUS
EVIDENCE OF LIFE, CALLED
STROMATOLITES. LOOK IN THE UPPER
LEFT HAND PICTURE YOU SEE THE
MIDDLE OF THE CLIFF LOZENGE
BASED SHAPE STRUCTURES ABOUT
FOUR TO FIVE METERS THICK. THOSE
ARE MICROBIAL RREEFS. LOOK AT
THE RIGHT YOU SEE SOME OF THESE
TYPES OF STRUCTURES CLOSE UP,
THERE ARE UPWARD DOMAIN LAMB
NATIONS, AND OHIO LA MY NATION,
YOU CAN SEE IN THE LOWER LEFT
PLACE CALLED SHARK BAY WESTERN
AUSTRALIA, THERE ARE PLACES
TODAY WHERE THESE KINDS
LAMINATED STRUCTURES FORM AND
THEY ARE FORMED BY MICROBIAL
COMMUNITIES. SO WE ARE USED TO
THINKING OF RREEFS AS BEING
STRUCTURES BUILT BY QUARRELS BUT
MOST OF EARTH HISTORY RREEFS
WERE BUILT BY MICROBIAL
COMMUNITIES. THEN THERE IS
CHEMICAL EVIDENCE FOR LIFE.
THINGS LIKE DNA AND PROTEINS DO
NOT PRESERVE WELL. THE OLDEST
DNA WE KNOW OF IS ABOUT 2
MILLION YEARS. BUT OTHER
MOLECULES, PARTICULARLY LIPIDS
CAN PRESERVE GEOLOGIC RECORD
VERY WELL, FOR YEARS I USED TO
TELL MY STUDENTS WHEN THEY DIE
THE LASTING PART OF THEM
AVAILABLE FOR THEIR DESCENDENTS
TO CONTEMPLATE WOULD BE THEIR
CHOLESTEROL, THAT IS NOT SO FAR
OFF. SO VERY FEW EUKARYOTS
PRODUCE VARIETY OF DIFFERENT
STEROL, THEIR CARBON SKELETONS
ARE PRESERVABLE IN THE RECORD
AND THEY PROVIDE AN AUGMENTED
VIEW OF BIOLOGICAL DIVERSITY IN
THESE ROCKS. THE SAME THING IS
TRUE OF THINGS LIKE BACTERIA, A
VARIETY OF -- SO WE HAVE THIS
MOLECULAR FOSSIL RECORD TO
COMPLIMENT THAT OF MORPHOLOGY.
THEN MICROBES CAN ACTUALLY
INFLUENCE CHEMICAL STRUCTURE OF
SEDIMENTS BECAUSE OF THEIR
METABOLISM. IF YOU GO DOWN TO
BAHAMAS AND LOOK AT THE RATIO OF
THE TWO -- THE TWO STABLE CARBON
ISOTOPES, C 13 AND C 12 IN THE
CARBON ATTACHED.
S YOU WILL FIND THAT RATIO ON
THE ARBITRARY SCALE IS
ESTABLISHED TO DISCUSS THESE
THINGS IS ZERO. THAT IS VERY
MUCH LIKE A STANDARD THAT IS
JUICED. LOOK AT ORGANIC --
USED. LOOKING AT ORGANIC MATTER
IN THE SIAMESED.
S IT IS DEPLETED IN 13C BY 25
PARTS PER THOUSAND. THAT
DEPLETION REFLECTS THE FACT THAT
DURING PHOTOSYNTHESIS CARBON
DIOXIDE WITH THE LIGHTER STABLE
ISOTOPE C 12 IS PREFERENTIALLY
INCORPORATED INTO ORGANIC
MOLECULES. SO THAT GIVES US A
CHEMICAL MARK E FOR A BIOLOGICAL
CARBON CYCLE. AND THAT IS WHAT
WE SEE IN ROCKS THAT ARE 800
MILLION YEARS OLD AND AS THIS
DIAGRAM INDICATES YOU SEE THAT
IN MUCH OLDER ROCKS AS WELL.
THE POINT IS THAT IN FACT WHEN
YOU LOOK AT THESE ROCKS MORE
ANCIENT THAN ANYTHING THAT
CONTAINS ANIMALS, THE FINGER
PRINTS OF BIOLOGY ARE
EVERYWHERE. WE CAN INTERPRET
THOSE BY LOOKING AT MODERN
PLACES LIKE THIS PICTURE YOU SEE
IN THE TURKS AND KAKOS ISLANDS
WHERE I HAVE WORKED RECENTLY, WE
CAN LOOK AT MODERN MICROBIAL
SYSTEMS AND UNDERSTAND HOW WILL
LIVING MATS ARE BASICALLY
TRANSFORMED INTO THIS
GEOLOGICALLY PRESERVABLE
INFORMATION. WE KNOW THERE IS A
ANIMAL GEE LOGICAL RECORD OF
MICROBES -- GEOLOGICAL RECORD OF
MICROBES. LET'S DOUBLE THE AGE
FIRST OF ALL ALL. YOU ARE B LOT
BEAUTIFUL EXPOSED ROCKS NORTHERN
SIBERIA, ABOUT 1,500,000,000
YEARS OLD, AS YOU SEE OBJECT
RIGHT THEY HAVE CYANO BACTERIA
AN EUKARYOTIC CELLS, TEN MICRON
SCALES. LOOK AT CARBON NITROGEN
AND SULFUR ISOTOPES THEN THEIR
ISOTOPIC SYSTEMATIC TELLS THEY
WERE BIOLOGIC CARBON SULFUR AND
NITROGEN CYCLES THEN. THERE ARE
MOLECULAR BIOMARKERS IN THESE
ROCKS. AND I LOVE THE PICTURE ON
THE LOWER LEFT, BECAUSE FIRST OF
ALL MY RUSSIAN COLLEAGUE
STANDING THERE IS EXACTLY TWO
METERS TALLER THAN HIS HAT SO A
VERY CONVENIENT MARKER THAT YOU
MIGHT SAY I SEE WHAT YOU POINT
OUT HERE, RIGHT IN THE CENTER
THERE IS SORT OF ROUND
STRUCTURE, I BET THAT SOMEONE OF
THE MICROBIAL RREEFS. IT IS.
IT IS MICROBE YAHT REEF, MAYBE
THE SIDE -- MICROBIAL REEF,
MAYBE SIZE OF A BIN SOMETHING
LIKE THAT. SO IF YOU NOTICE THE
POINTS, TURNS OUTS TO BE 15
POINT QUESTION BECAUSE IF YOU
LOOK AT WHERE MY FRIEND MISHA IS
STANDING, IT IS A CURVED SURFACE
AND THAT IS PROBABLY A -- IT IS
A MICROBIAL REEF AS LARGE AS A
LARGE LECTURE HALL. IF YOU LOOK
AT BEHIND HIM THAT IS ASTRO MAT
LYTIC RE,F THAT COVERS THE CLIFF
WALL, THAT IS A REEF WITH THE
DIMENSIONS MAYBE THE SIZE OF ONE
OF YOUR RESEARCH WHICH
WOULDIWHIBUILDINGS.SHOWING MICRA
LONG HISTORY THAT LONG
ANTI-DATES ANYTHING BUILT BY
CORALS. SO DOUBLE THE AGE
AGAIN, GO BACK TO ROCKS IN
WESTERN AUSTRALIA, NEARLY 3 1/2
BILLION YEARS OLD AND ARE SOME
OF THE OLDEST ROCKS WELL ENOUGH
PRESERVED TO ASK QUESTIONS ABOUT
BIOLOGY. WHAT DO WE FIND WHEN WE
LOOK AT THOSE? TURNS OUT THEY
ARE STROMATLO LIGHTS IN THEM SO
MICROBIAL COMMUNITIES COVERING
SURFACES WITHIN ANCIENT ZONE. WE
DON'T FIND MOLECULAR FOSSILS
DISCERNIBLE BUT WE STILL SEE
THIS ISOTOPIC SEPARATION BETWEEN
CARBONATE AND ORGANIC CARBON
THAT TELL US THERE WAS A
BIOLOGICAL CARBON CYCLE. WE CAN
ALSO LOOK AT SULFUR ISOTOPES AND
COME TO THE SAME CONCLUSION
ABOUT A BIOLOGICAL SULFUR CYCLE
THINGS THAT HAVE BEEN CALLED
FOSSILS HAVE BEEN DESCRIBED SO
IF YOU LOOK AT THIS IMAGE ON THE
LEFT THOSE ARE TEN MICRON
ORGANIC SMEARS THAT HAVE BEEN
INTERPRETED AS FOSSILS.
BUT IF YOU LOOK AT THE BLACK
SPHERES YOU SEE IN THE UPPER
RIGHT, THOSE ARE NOT FOSSILS
THOSE ARE PRODUCTS OF ORGANIC
MATTER REMOBILIZATION BY HYDRO
THERMAL FLUID FLOW AND TURNS OUT
THAT ALL OF THESE ROCKS THREE
AND A HALF BILLION YEARS OLD
HAVE BEEN SUBJECT TO HYDRO
THERMAL FLUID FLOW SO WE HAVE TO
BE AGNOSTIC ABOUT FOSSILS PER
SE. I THINK THE EVIDENCE IS
STRONG THAT SUGGEST THAT LIFE
HAS BEEN A PART OF THE EARTH
SYSTEM SINCE VERY EARLY IN OUR
PLANET HISTORY. THAT IS THE
FIRST TIME WE HAVE ROCKS THAT
CAN BE INTERROGATED FOR
QUESTIONS OF BIOLOGY, LIFE IS
ALREADY THERE. THERE IS
UNCERTAINTIES ABOUT WHAT THE
NATURE AND DIVERSITY OF THAT
LIFE WAS. BUT ONE THING IS CLEAR
FROM GEOCHEMISTRY, THAT THIS WAS
A WORLD WITHOUT OXYGEN. SO WHAT
ARE THE CONSEQUENCES OF HAVING A
WORLD WITHOUT OXYGEN? IF YOU ARE
INTERESTING IN AUTOTROPHY, THERE
ARE MORE ELECTRON DONORS AND FEW
THAT ELECTRON ACCEPTORS. AS WE
SEE MORE IN A SECOND, IN THIS
WORLD THERE WOULD HAVE BEEN VERY
LIMITED PHOSPHORUS AVAILABLE FOR
PRIMARY PRODUCTION BECAUSE FOR
ONE THING PHOSPHATE WOULD BE
OBSERVED ABSORBED ON IRON
MINERALS AND BE REMOVED FROM
BIOLOGICAL CONSIDERATIONS. THERE
WOULD HAVE BEEN SOME NITROGEN
NITRATE MADE BY ABIOTIC NIGH
THROW GENERAL FIXATION,
LIGHTNING PASSING THROUGH THE
ATMOSPHERE PRODUCE AT LEAST
COUPLE OF PERCENT OF THE
NITROGEN FIXED BY MICROBES
TODAY. IMPORTANTLY FOR THINKING
EVOLUTION, A LOT OF TRACE METALS
ARE REDOX SENSITIVE AND SO IN A
WORLD WITHOUT OXYGEN YOU HAVE
MORE IRON COBALT AND MANGANESE
BUT THINGS LIKE COPPER ALUMINUM
AN ZINC WOULD BE MUCH LESS
ABUNDANCE THAN THEY ARE TODAY.
ALL THAT CHANGES ABOUT
2.4 BILLION YEARS AGO, THE GREAT
OXYGENATION EVENT. AND SEVERAL
LINES OF EVIDENCE; I WON'T TALK
THE TIME TO RUN THROUGH THEM,
BUT BE HAPPY TO TALK ABOUT THEM
TELL US THIS IS WHEN WE FIRST
STARTED TO GET A PERMANENT
QUANTITY OF OXYGEN GAS IN THE
ATMOSPHERE AND SURFACE OCEAN.
ONLY ONE SOURCE OF OXYGEN
POSSIBLE TO FUEL THAT AND THAT
IS CYANO BACTERIA. FOR THE FIRST
BILLION YEARS OF LIFE EARTH WAS
LARGELY A WATER PLANET, THAT IS
WHILE THERE WAS SOME CONTINENTAL
CROSS VERY LITTLE WAS EMERGENT.
IF YOU HAD TAKEN A SATELLITE
PHOTO OF THE WORLD 3 1/2 BILLION
YEARS AGO, YOU WOULD HAVE SEEN
VOLCANOS STICKING OUT, MAYBE
SOME MICROBE COTTONE,LLE MASSES
BUT LARGELY YOU WOULD HAVE SEEN
WATER. THAT KIND OF WORLD THERE
IS LIMITED WEATHERING AND
EROSION SO THERE IS LESS
PHOSPHORUS COMING TO THE SYSTEM.
AS I ALREADY MENTIONED, THERE
WERE A LOT OF IRON IN SEA WATER,
THAT RESULTS IN PRECIPITATION OF
PHOSPHORUS AS PHOSPHATE BY
ITSELF, PHOSPHATE MINERALS
BECAUSE THEY ARE LIMITED OXYGEN,
THERE WOULD HAVE BEEN LIMITED
ORGANIC REMAIN RAILIZATION SO
THERE WASN'T MUCH OF A
REMINERALIZATION OF NUTRIENTS.
IN THIS WORLD IT IS VERY LIKELY
THAT MUCH OF THE PHOTOSYNTHESIS
WAS DONE BY THESE PAN OXIC FLOW
SYNTHETIC BACTERIA, PARTICULARLY
ONES THAT AREN'T ABLE TO USE
FERRIS IRON. WHY DOES THAT
CHANGE 2.4 BILLION YEARS AGO?
THE MAIN THING THAT SEEMS TO
HAPPEN IS THE CONTINENTS HAVE
MERGED. THIS IS A RESULT OF
COOLING MANTEL, WE TALKED ABOUT
IN MORE DETAIL, IF YOU ARE
INTERESTED IN IT BUT BECAUSE OF
THAT CONTINENTS EMERGE CHANGES
THE DYNAMICS OF THE PHOSPHORUS
CYCLE IN A WAY THAT WOULD FAVOR
CYANO BACTERIA. HOW MUCH OXYGEN
DO WE GET AT THAT POINT? ANSWER
IS PROBABLY NOT MUCH. THERE IS
DEBATE ON THIS BUT SOMEWHERE ON
THE ORDER OF 1 TO A FEW PERCENT
OF PRESENT DAY OXYGEN LEVELS
WERE IN THE ATMOSPHERE. MOST OF
THE OCEANS REMAIN AN OXIC THERE
ARE VARIETY OF DIFFERENT
GEOCHEMICAL INDICATORS OF THIS
ABUNDANCE AS ISOTOPES OF REDOX
SENSITIVE ELEMENTS. SO STARTS
MILLION DOLLAR AGE IF YOU WILL.
ONE CONSEQUENCE OF MODEST AMOUNT
OF OXYGEN TO ATMOSPHERE SURFACE
OCEAN IS EXPAND OXIDANT POOLS
FOR RESPIRATION AND
CHEMOSYNTHESIS, YOU INCREASE
ORGANIC MATTER WHICH RETURN MORE
NUTRIENTS TO THE WATER COLUMN
FOR AND CYANO BACTERIA ARE
ECOSYSTEM ENGINEERS AS THEY ADD
OXIC TO THE ZONE THEY SCRUB IT
CLEAN OF ALTERNATIVE ELECTRON
DONORS AND SO BASICALLY BECOMES
THE CYANO BACTERIA WORLD. THERE
IS A NEW TYPE OF LIFE, THE
EUKARYOTIC CELL. LAST COMMON
ANCESTOR OF LIVING EUKARYOTS HAD
MITOCHONDRIA THAT WERE CAPABLE
OF RESPIRATION AND THAT BECOMES
POSSIBLE AS OXYGEN STARTS TO BE
PERSISTENT PART OF THE
ENVIRONMENT. THIS SHOWS US
EUKARYOTS BACK TO 700 MILLION
YEARS AGO OR SO. BY A BILLION
YEARS OR SO WE HAVE RED AND
GREEN ALGAE, TWO LARGER ONES ON
YOUR LEFT. WE HAVE OTHER SIMPLE
MULTI-CELLULAR EUKARYOTS THAT GO
BACK TO ALMOST AS OLE AS
EUKARYOTS AS A WHOLE. WITH THIS
OXYGEN ECOSYSTEMS EXPAND THOUGH
CONTROL REMAINS FIRMLY UNDER
BACTERIAL CONTROL. IN FACT
DESPITE THE FACT THAT WE HAVE
GREEN AND RED ALGAE MORE THAN A
BILLION YEARS AGO, MOLECULAR
FOSSILS TELL US THAT EUKARYOTS
ONLY BECAME MAJOR PRIMARY
PRODUCERS AROUND 6 HUNT MILLION
YEARS AGO. BOTH FOSSILS AN
MOLECULAR MARKERS INDICATE THAT.
WE FIRST START SEEING ABUNDANT
GREEN STERINES ONLY 600 TO 580
BILLION YEARS AGO. SO SOMETHING
IS CHANGING. SOMETHING IS
CHANGING. AND WHAT WE THINK IS
CHANGING IS THE NUTRIENTS STATUS
OF THE WORLD. BECAUSE IF YOU
LOOK AT OCEAN TODAY WHERE
NUTRIENT LEVELS ARE LOW, PRIMARY
PRODUCTION IS DOMINATED BY CYANO
BACTERIA. THE CENTRAL DRIVER OF
OCEAN SPRINGS BUT MORE NUTRIENTS
YOU START BRINGING IN LARGER
EUKARYOTIC CELLS, MORE GREEN
ALGAE, IF YOU ADD A LOT OF
NUTRIENTS YOU GET DIATOMS,
IMPORTANT PRIMARY PRODUCERS
TODAY. ALWAYS INTERESTING BUT
THAT WHAT WE SEE IN SPACE
MIRRORS WHAT WE SEE IN TIME.
THAT WE HAVE CYANO BACTERIA ONLY
NEAR THE END OF THE DO WE SEE
GREEN ALGAE AND ONLY THE LAST
150 MILLION YEARS AGO DO WE SEE
DIATOPS: WHAT CHANGES? 600
MILLION YEARS AGO? ONE THING WE
NOTICED THAT IS THE WHOLE RECORD
OF PHOSPHORUS CHANGES. THIS IS
THERE IS ECONOMIC CONSEQUENCE OF
THIS BECAUSE THE PHOSPHATE USED
IN FERTILIZER WHICH IS A WASTING
RESOURCE AS IT TURNS OUT, AN OLD
STORY, IS ALMOST EXCLUSIVELY
FOUND IN ROCKS THAT ARE 600
MILLION YEARS OLD AND YOUNGER.
THERE IS ONE DEPOSIT IN CHINA
WITH MORE SEDIMENTARY PHOSPHATE
THAN THE ENTIRE GEOLOGIC RECORD
BEFORE THAT TIME. THIS IS A
TIME OF MAJOR MOUNTAIN BUILDING.
I THINK PROBABLY FOR THE FIRST
TIME THE MANTEL HAS COOLED
ENOUGH THAT WE GET HIM LAYIAN
STYLE MOUNTAINS THAT INCREASES
THE PHOSPHATE COMING INTO THE
OCEANS, THAT INCREASES OXYGEN
PRODUCTION, THAT INCREASES IF
YOU WILL THE REMINERALIZATION OF
ORGANIC MATTER SO WE STRENGTHEN
THIS UPWELLING WHICH TODAY IS
RESPONSIBLE FOR MOST PHOSPHORUS
CONSUMED BY LACTIN IN THE OCEAN
SO WE THINK THERE IS A TECTONIC
EVENT WHICH WILL CHANGE THE
NUTRIENT DYNAMICS OF THE WORLD
AND THAT HAS TWO CONSEQUENCES.
FIRST INDEPENDENT THIS EVIDENCE
THERE'S LOTS OF EVIDENCE THAT
TELL US OXYGEN IS GOING UP AND
STARTING ON THE ROAD TO THE
PRESENT DAY AMOUNTS THAT WE SEE
TODAY. ALSO AT THE SAME TIME WE
SEE OUR FIRST RECORD OF
MICROSCOPIC ANIMALS. IT IS
LIKELY THERE IS A CAUSAL BRIDGE
THAT RUNS FROM EARTH TECTONIC
HISTORY TO CHANGES IN NUTRIENT
DYNAMICS THAT CHANGES IN FOOD
AND OXYGEN AVAILABILITY. AND
ULTIMATELY RESULTS IN ANIMAL
DIVERSIFICATION. LET ME FINISH
UP THEN. BEGINNING 600 TO 550
MILLION YEARS AGO THIS NEW WORLD
STARTS TO TAKE SHAPE. A WORLD
WITH ANIMALS AND EVENTUALLY
PLANTS. FROM THE STANDPOINT OF
BACTERIA, THIS IS SIMPLY GIVING
THEM NEW TO CARBON, NOT ONLY
ANIMALS ARE INNER RELATED WITH
HUNDREDS OF BACTERIA BUT PLANTS
ARE AS WELL. WE ARE JUST
LEARNING THE PLANT MICROBIOME
BUT IT IS EXTENSIVE AND THERE
IS'S INTIMATE PHYSICAL LOGICAL
INTERACTIONS. TO SUMMARIZE THEN,
MICROBES PROVIDE THE PUNNED
MENTAL ECOLOGIC CIRCUITRY OF
LIFE ON EFFORT GEOLOGIC RECORDS
OF LIFE IS LONG, ALMOST AS LONG
AS THE RECORDS OF THE PLANET
ITSELF AND IT IS MOSTLY
MICROBIAL. COMPLEX
MULTI-CELLULAR LIFE WAS
ENTERCOLLATED TO FUNCTIONING
ECOSYSTEMS BUILT ON MICROBIAL
METABOLISMS AND THEN I ALWAYS
STICK THIS IN BECAUSE I TALK TO
BIOLOGIES THAT WHAT IS UNUSUAL
ABOUT THE EARTH MIGHT IN THE BE
THAT LIFE ORIGINATED ONLY HERE
BUT THAT IT HAS PERSISTED FOR 4
BILLION YEARS THANKS TO
MICROBES. SO WITH THAT, THANKS
VERY MUCH, I WILL STOP SHARING
AND MAYBE WE CAN HAVE SOME
DISCUSSION.
>> THANK YOU, VERY MUCH FOR THIS
EXTRAORDINARY PRESENTATION. WE
HAVE A WHOLE BUNCH OF QUESTIONS
FOR YOU, THE ONE THAT POPPED UP
A COUPLE OF TIMES ACTUALLY IN
ADVANCE OF YOUR TALK SEVERAL
PEOPLE SENT ME MESSAGES ASKING
WHAT IS YOUR DEFINITION OF LIFE
>> THAT IS A GREAT QUESTION. FOR
A LOT OF BIOLOGISTS THEY STARTED
TO TAKE THE CONNER STEWART VIEW
OF -- ONCE FAMOUSLY SAID HE
DIDN'T KNOW HOW TO DEFINE
PORNOGRAPHY BUT KNEW IT WHEN HE
SAW IT, I THINK A LOT OF
BIOLOGISTS ARE CONTENT WITH
THAT, PHYSICISTS AND
PHILOSOPHERS ARE NOT CON FIENTS
WITH THAT. THE DEFINITION I LIKE
BEST COMES FROM JERRY JOYCE OF
THE SCRIPS IN CALIFORNIA JERRY
DEFINED LIFE AS A
SELF-SUSTAINING CHEMICAL SYSTEM
CAPABLE OF DARWINIAN EVOLUTION.
WHAT I LOVE ABOUT THAT IS IT
MAKES EVOLUTION MORE OR LESS
DEFINITIONAL FOR LIFE. I THINK
THAT'S LIKELY TO HOLD NOT JUST
ON EARTH BUT WHEREVER WE MIGHT
FIND SCIENCE OF LIFE IN THE
UNIVERSE. -- SIGNS OF LIFE IN
THE UNIVERSE.
>> WE HAVE A QUESTION AS TO
WHETHER CAN LIFE BE SUSTAINED IN
A SULFUR CYCLE?
>> NOT BY ITSELF. THERE ARE
THINGS CALLED SULFUR REDA, CRAZY
ENVIRONMENTS WHERE YOU ACTUALLY
HAVE ALL THE ELEMENTS OF A
SULFUR CYCLE THAT CYCLES BACK
AND FORTH BETWEEN SULFIDE AND
SULFATE. SO YES, WE KNOW THAT
SULFIDE CAN BE USED TO FUEL
CHEMOAUTOTROPHY AND
PHOTOSYNTHESIS. WE KNOW SULFATE
CAN BE USED FOR RESPIRATION. IN
THAT SENSE, YES, YOU CAN HAVE A
LOT OF ENERGY METABOLISM DRIVEN
BY SULFUR CYCLE. NOW, WHAT MAKES
IT COMPLICATED, FOR MOST OF
EARTH HISTORY, THE AN AEROBIC
ENVIRONMENTS OR AN OXIC
ENVIRONMENTS OF THE OCEANS
WEREN'T RICH IN SILVER BUT IN
IRON. WE KNOW THAT BECAUSE WE
HAVE THESE BIG FORMATIONS CALLED
IRON FORMATION WHICH IS ARE
WHERE WE GET MOST IRON THAT HAS
BEEN MINED BY HUMAN. MOST OF
THOSE FORMED EARLY IN EARTH'S
HISTORY. TURNS OUT SULFUR AND
IRON REACT. VERY QUICKLY TO FORM
FOOL'S GOLD OR PYRATE. ON THIS
EARLY WORLD THAT DIDN'T HAVE ANY
OR MUCH OXYGEN, THERE WAS A LOT
OF IRON AND NOT MUCH SULFUR AT
LEAST DISSOLVED FLUIDS THAT
SUSTAIN BIOLOGY. SO WHILE YOU
COULD -- YOU HAD VERY LITTLE
SULFATE, SULFATE PRODUCTION
OCCURRED BUT IT COULDN'T HAVE
BEEN THE MAJOR OXIDANT. AND YOU
HAD SOME SULFIDE USED IN
PHOTOSYNTHESIS BUT PROBABLY MOST
SULFIDE AS SOON AS IT APPEARED
GOT SNAPPED IN IRON SULFIDE
MINERALS. IN PRINCIPLE YOU CAN
HAVE AN ECOSYSTEM SUSTAINED BY
THE ENERGETICS OF A SULFUR
CYCLE, IN EARTH HISTORY, IT IS A
LITTLE MORE COMPLICATED BECAUSE
OF IRON.
>> IS THERE RESPIRATION DURING
SULFUR CYCLE?
>> YES. SO WILL IS A WHOLE FLEET
OF BACTERIA THAT RESPIRE RATHER
THAN USING OXYGEN, THEY USE
SULFATE. YOU GET LESS ENERGY
FROM THAT REACTION. BUT I SAID
BRIEFLY, IT IS PROBABLY THE
MAJOR WAY EVEN IN THE OCEANS
TODAY, THAT SEDIMENTARY ORGANIC
MATTER IN THE OCEAN GETS
RECYCLED. NOW THE OCEANS TODAY
HAVE MORE SULFATE IN THEM THAN
ANY PREVIOUS TIME IN EARTH
HISTORY. SO IT IS AVAILABLE AS A
MAJOR OXIDANT WHERE OXYGEN IS
ABSENT.
>> WE HAVE ANOTHER QUESTION,
WHAT ARE YOUR THOUGHTS ABOUT
WHAT THE FIRST LIFE FORM MAY
HAVE ACTUALLY LOOKED LIKE.
>> THAT IS A GREAT QUESTION. I
THINK THERE IS TWO WAYS TO GO
ABOUT A LONG ROUNDED WAY OF
SAYING I DON'T KNOW. IF YOU GO
FROM PRESENT DAY LIFE AND GO
BACKWARD, YOU CAN COME TO AT
LEAST SOME REASONABLE
APPROXIMATION OF WHAT THE LAST
COMMON ANCESTOR OF LIFE WAS
LIKE. DNA AND GENETIC CYCLES NOT
UNLIKE WHAT WE SEE TODAY,
MEMBRANES WE SEE TODAY. THE
PROBLEM IS THAT IS NOT THE FIRST
LIFE, THAT STUFF IS THE PRODUCT
OF SUBSTANTIAL INTERVAL OF
EVOLUTIEVOLUTION. THE FIRST LIFE
ARE TWO CAMPS, I MUST ADMIT MY
WORK IS MORE CONCERNED HOW WE
SEE RECORDS FOR LIFE ONCE
ESTABLISHED BUT FRIENDS DO
ORIGIN OF LIFE WORK. THE FIRST
THING JERRY JOYCE CALL LIFE THAT
IS EVOLVING SELF-SUSTAINING
SYSTEMS ARE RNA, RNA LIKE
MOLECULE WE HAVE KNOWN SINCE
WORK OF TOM CHECK THAT RNA IS
NOT SIMPLY THE MIDWIFE FOR
PRODUCTION OF PROTEINS. BUT CAN
WORK AS AN ENZYME ITSELF, CALLED
RIBOSOMES. RIBOSYMES. SO ONE
CAMP SEES EARLY SELF-SUSTAINING
SYSTEMS BEING BASED ON NUCLEIC
ACIDS THAT ARE BOTH
INFORMATIONAL ENSIGH MATTIC.
THAT HAS A -- ENZYME ATTIC. THAT
IS A PROBLEM HOW WE INCORPORATE
PROTEIN IN THE LIFE THAT MUST
HAVE BEEN PRESENT IN THE LAST
COMMON ANCESTOR. THERE IS A
LOYAL OPPOSITION. PEOPLE WHO
TEND TO SEE LIFE AS BEGINNING AT
HYDRO THERMAL VENTS IN THE OCEAN
WHERE ONE SEES YOU CAN HAVE
POSITION WHERE YOU GET THESE
STRONG PH GRADIENTS DEVELOPING
AND YOU HAVE SOMETHING SIMILAR
TO THE KINDS OF CELLULAR
PROCESSES THAT GIVE RISE TO
METABOLISM TODAY UNDER PLAUSIBLE
PREBIOTIC CONDITIONS PEOPLE HAVE
BEEN ABLE TO SYNTHESIZE A NUMBER
OF CONSTITUENT PARTS OF THE KREB
PSYCH. BOTH OF THESE THINGS ARE
INTERESTING, THEY BOTH GIVE US
SOME ENSIGHT. THEY BOTH --
INSIGHT. THEY SUFFER FROM THE
DIFFICULTY OF GETTING AN
INTEGRATION BETWEEN NUCLEIC ACID
AND PROTEINS THAT IS PRESENT IN
ALL LIFE THAT WE KNOW. THAT IS
PRETTY MUCH WHERE WE ARE. WE
KNOW IT MUST HAVE HAPPENED THERE
BUT HOW WE GET THERE WE REMAIN
IN SUBSTANTIAL IGNORANCE.
>> SUGGESTING THAT ENERGY
RECEDES GENES.
>> DEPENDS WHO YOU TALK TO I
WENT TO A MEETING IN JAPAN A FEW
YEARS AGO AND ONE OF THE NUCLEIC
ACID PEOPLE CAME UP TO ME AND HE
SAID WELL, YOU KNOW, YOU CAN
HAVE LIFE WITHOUT ENERGY
METABOLISM AND MY RESPONSE IS
YEAH, IT IS PROBABLY TRUE BUT
LIFE BECOMES INTERESTING WHEN IT
HAS ENERGY METABOLISM, THAT'S
WHEN IT STARTS INTERACTING WITH
THE EARTH IN A SUBSTANTIAL WAY.
>> IF WE DON'T HAVE A CELL
ENCOMPASSED BY MEMBRANE, IN AWE
PRESENT KNOWLEDGE CAN A GENE
FUNCTION IN AN EXRA CELLULAR
MILIEU?
>> THAT IS AN IMPORTANT
QUESTION. WHILE SOME HAVE DONE
TEST TUBE EXPERIMENTS, THAT
SUGGEST YOU CAN GET SOMETHING
CLOSE TO SELF-REPLICATION YOU
CAN HAVE TWO RECIPROCAL RNA
MOLECULES THAT ESSENTIALLY
CATALYZE THE REPLICATION OF THE
OTHER. ON THE OTHER HAND A
NUMBER OF PEOPLE INCLUDING MY
FRIEND JACK VAN MORE TRYING TO
CARRY OUT THESE REACTIONS WITHIN
A MEMBRANE ENCLOSURE. A, IT
SEEMS TO MAKE THEM WORK BETTER
BECAUSE YOU DON'T HAVE DILUTION
IF NOTHING ELSE. TURNS OUT ONE
THING THAT IS DIRT EASY TO MAKE
ON THE EARLY EARTH WHO ARE LIPID
MICELLS, THAT ALL YOU NEED IS
PREBIOTIC REACTS THAT MAKE FATTY
ACIDS AND THINGS LIKE THAT. IF
YOU SPLASH THEM THEY WILL
SELF-ORGANIZE INTO LIPID
ENVIRONMENTS, PEOPLE LIKE DAVID
DEEMER IN CALIFORNIA HAVE
ACTUALLY SHOWN THAT IF YOU
REPEATEDLY WET AND DRY SOME OF
THESE SYSTEMS THAT ORIGINATE
WITH LIPIDS HERE AND NUCLEIC
ACIDS OVER HERE YOU HAVE SYSTEMS
IN WHICH NUCLEIC ACID MOLECULES
ARE ACTUALLY ENCAPSULATED WITHIN
THE LIPIDS. IT IS VERY
IMPORTANT AND I THINK SOME SORT
OF EARLY SIMPLE LIPID ONE PART
OF EVOLVING SYSTEM VERY, VERY
EARLY.
>> DAN SENT A QUESTION IT SOUNDS
AS IF BILLIONS OF YEARS WERE
REQUIRED FOR EUKARYOTS TO E
INVOLVE ON OTHER PLANETS IN THE
UNIVERSE. CAN YOU IMAGINE A
CIRCUMSTANCE IN WHICH IN PROCESS
WOULD OCCUR FASTER?
>> YES. GOOD QUESTION, DAN. I'M
JUST BEEN -- ONE OF MY SIDE JOBS
I REVIEW BOOKS FOR LONDON TIMES
I REVIEWED A BOOK CALLED
POSSIBILITY OF LIFE BY JAMIE
GREEN. IT IS THIS WONDERFUL
INFORMATIVE BOOK ABOUT HOW WE
MIGHT THINK ABOUT LIFE BEYOND
THE EARTH THE REASON RELEVANT
HERE IS THAT MANY PEOPLE WILL
TALK ABOUT HOW THERE IS A LOW
PROBABILITY OF ACHIEVING
EUKARYOTS OR MULTI-CELLULARITY
OR LOW LOAN INTELLIGENCE,
TECHNOLOGICAL HUMANS ARE JUST A
WHISPER OF INTERVAL OF HISTORY.
BUT THE TIME SCALE OF EVOLUTION,
I THINK IN MANY WAYS IS
CONSTRAIND BY TIME SCALE OF
EARTH OXYGEN HISTORY. ON ANOTHER
PLANET, WE MIGHT HAVE GOTTEN
OXYGEN MUCH MORE QUICK, WHICH
BARRIERS TO EUKARYOTS AND
ULTIMATELY COMPLEX
MULTI-CELLULARITY, WERE LIFTED
SO ALTHOUGH IT TOOK FOUR AND A
HALF BILLION YEARS TO GET FROM
REAL LIFE TO US ON EARTH, I'M
NOT SURE THAT IS ANYTHING LIKE A
FUNDAMENTAL TIME SCALE.
I THINK IT IS AS MUCH A PRODUCT
OF PLANETARY HISTORY AS IT IS
BIOLOGICAL POSSIBILITY.
>> YOU TALKED GREAT OXIDATION
EVENT. IS THERE EVIDENCE OX
GENERAL COULD HAVE BEEN
INTRODUCED AS SLOWER RATE,
SMALLER AMOUNTS PRODUCING GARAGE
WOULD BACTERIAL AND OTHER? IS
THERE ANY EVIDENCE FOR THAT
>> THAT IS A GOOD QUESTION AND
INTERESTING PATTERN THERE ARE
FOUR OR FIVE LINES OF
GEOCHEMICAL EVIDENCE THAT ALL
AGREE OXYGEN TENSION BEFORE
2.4 BILLION YEARS AGO HAD TO BE
VERY LOW. THERE IS MASS
INDEPENDENT FRACTS NATION OF
SULFUR ISOTOPES. WHICH BASICALLY
SHOWS THAT THERE ARE SOME
PHOTOCHEMICAL PROCESSES THAT
WILL OCCUR IN THE ATMOSPHERE
WHEN OXYGEN IS ESSENTIALLY
ABSENT THAT CAUSE FRACTIONATIONS
AMONG THE FOUR STABLE ISOTOPES
OF SULFUR THAT DIFFER FROM THOSE
THAT ARE CHARACTERISTIC OF
BIOLOGY. MODELING SUGGESTS THAT
THAT WILL ONLY HAPPEN IF OXYGEN
TENSION IN THE ATMOSPHERE ARE
SOMETHING LIKE TEN TO THE
NEGATIVE 6 OF PRESENT DAY VALUE
SO VERY LOW, TOO LOW FOR
METABOLISM. THAT SEEMS TO
CHANGE. AND CHANGE DRAMATICALLY
AND FOREVER BETWEEN 2.4 AND
2.2 BILLION YEARS AGO. HAVING
SAID THAT, THERE ARE NUMBER OF
REPORTS IN OLDER BLOCKS OF WHAT
HAVE BEEN CALLED WHIFFS OF
OXYGEN, THERE COULD HAVE BEEN
SOME LOCAL TRANSIENT SMALL
ACCUMULATION OF OXYGEN IN SOME
OCEANS PERHAPS LAKES. THAT
SUGGEST THE CAPACITY FOR OXYGEN
PHOTO SYNTHESIS EXISTED BUT
EITHER BECAUSE TOTAL RATES OF
PRIMARY PRODUCTION WERE VERY
LOW, DUE TO NUTRIENT STARVATION
OR THERE IS ENOUGH IRON AROUND
THAT PBS SYNTHETIC BACTERIAER
OTHER TYPES FAVORED ARE STILL IN
ARGUMENT BUT IT SUGGESTS THE
CAPACITY FOR OXYGENIC
PHOTOSYNTHESIS, THE FIRST OXYGEN
PRODUCING CYANO BACTERIA EXISTED
LONG BEFORE THERE WAS THIS GREAT
CHANGE IN THE ATMOSPHERE, AS I
MENTION BRIEFLY, A MAJOR CULPRIT
EXPLAINING THAT CHANGE IS THAT
IT IS ABOUT -- ONLY ABOUT THE
TIME OF GREAT OXYGENATION EVENT
THAT WE HAVE EVIDENCE THAT
CONTINUE INNOCENCE EMERGED ABOVE
SEA LEVEL IN A SUBSTANTIAL WAY.
THE REASON FOR THAT IS THAT WHEN
YOU HAVE A HOT MANTEL TWO THINGS
HAPPEN. ONE IS IT CAN'T SUPPORT
CONTINUE INNOCENCE WITH THIS
ISOSTATIC RELATIONSHIPS WE SEE
TODAY. CONTINUE INNOCENCE WOULD
BE HIGH ABOVE SEA LEVEL AND ALSO
THIS IS NEAT, A COLLEAGUE OF
MINE REBECCA FISHER HAS DONE
THIS NICE WORK SHOWING THAT A
HOT MANTEL CANNOT ACTUALLY
RETAIN MUCH WATER IN IT. SO
TODAY WE THINK THERE IS AN
OCEAN'S WORTH OF WATER IN THE
MANTEL PERHAPS SEVERAL OCEANS
WORTH OF MANTEL. ON THE EARLY
EARTH WHEN MANTEL WAS HOT MOST
OF THAT HAVE WOULD HAVE BEEN
DEGASSED SO IT COULD BE THAT YOU
HAVE MUCH MORE SEA WATER 3 OR 4
BILLION YEARS AGO THAN TODAY AND
AS THE MANTEL COOL PLATE
TECTONICS BRING SOME OF THAT
WATER BACK THE MANTEL AND KEEP
IT THERE, THAT WE GOT
RELATIONSHIPS BETWEEN CONTINUE
INNOCENCE AND OCEANS WE SEE
TODAY. IN A NUTSHELL, THERE'S
REASON TO BELIEVE THE TIMING AND
SOME OF THE DYNAMICS THIS
OXYGENATION EVENT OWE A DEBT TO
EARTH EVOLVING TECTONIC REGIMES.
>> WE HAVE A QUESTION I WANT TO
READ TO YOU, BECAUSE IT IS FROM
ONE OF YOUR FORMER STUDENTS.
FROM HENRY LEEVINE DISTINGUISHED
SCIENTIST HERE AT THE NATIONAL
INSTITUTES OVERMELT. HANK
WRITES, THANK YOU FOR YOUR
WONDERFUL LECTURE. JUST AS
COMPELLING AS YOUR LECTURES AT
OVERLAND WERE WHICH I LOVE, WHEN
YOU COMMENT ON THE CHEMICAL
NATURE OF ORGANICS DENTED ON
MARS AND SCIENCE OF PAST LIFE
AND YOU WILL ALSO COMMENT ON THE
QUOTE MICROFOSSILS CLOSE QUOTE,
FOUND IN METEOR ITS SAID TO BE
FROM MARS.
>> FIRST OF ALL I'M GLAD TO HEAR
YOU HAVE GONE ON TO GREAT
THINGS. THAT'S WHAT WE EXPECT
FROM OUR OVERLAND STUDENTS.
THOSE ARE GOOD QUESTIONS. AND I
CAN COMMENT ON BOTH. I'M SORRY
IF I HAVE TO POUR WATER ON
WI-FIES HERE BUT YES, THERE DOES
-- BIOPHYLES. BUT THERE DOES NOW
APPEAR TO BE REASONABLE
DETECTION OF ORGANIC MOLECULES
ON MARS. THAT IS EXCITING. THE
PROBLEM IS THERE IS AT LEAST
THREE DIFFERENT WAYS THOSE
MOLECULES COULD HAVE BEEN GOTTEN
THERE. -- COULD HAVE GOTTEN
THERE. THEY COULD HAVE
ORIGINATED FROM LIVING IS ALSO.
WE CAN'T RULE THAT OUT. ON THE
OTHER HAND, THERE IS NOTHING IN
THE COMPOSITION OF THE MOLECULES
THAT HAVE BEEN DISCOVERED THAT
WOULD MANDATE THAT. IT COULD BE
THAT THERE WAS PREBIOTIC HISTORY
ON MARS THE WAY THERE MUST HAVE
BEEN ON EARTH THAT LED TO LIFE
SO THERE ARE -- WE KNOW FROM THE
(INAUDIBLE) EXPERIMENT BACK IN
THE 1950s, THAT IT IS UNDER
THE RIGHT CONDITIONS WHICH
INCLUDE NO OXYGEN, BY THE WAY,
IT IS FAIRLY EASY TO MAKE
ORGANIC MOLECULES INCLUDING
AMINO ACIDS FROM ALL YOU NEED IS
ENERGY AND SIMPLE INORGANIC
MOLECULES. THEN THE THIRD
POSSIBILITY, MARS IS CONSTANTLY
BOMBARDED BY METEORIT EXS AND
WITH KNOW THERE ARE CLASSES OF
METEORITES THAT CONTAIN UP TO
20% ORGANIC MATTER SO
CARBONATION THOSE METEORITES
WERE PROBABLY IMPORTANT FOR
BRINGING THINGS LIKE CARBON AND
WATER TO THE EARTH WHEN EARTH
FORMED. SO YES WE HAVE THESE
MOLECULES. THINK THAT IS A TOUR
D E FORCE DETECTION BY MY
COLLEAGUES ON THE PERSEVERANCE
SCIENCE TEAM AS NAY ARE CAREFUL
TO POINT OUTS, THERE'S STILL
MUCH UNCERTAINTY AS TO THE
PROVIDENCE OF THOSE. THE OTHER
QUESTION WAS PAPER PUBLISHED IN
1996 WHICH TOOK -- LOOKED AT A
METEORITE INTERPRETED AS
ORIGINATING ON MARS AND FOUND
WHAT WERE DESCRIBED AS
MICROFOSSILS. THERE ARE THREE OR
FOUR LINES OF EVIDENCE INDUCED
TO MATERIALS IN THAT METEORITE
AS BEING PIE LOGICAL. TURNS OUT
THE CONTROVERSIAL PART OF THAT
IS NOT WHETHER THE METEORITE
COMES FROM MARS, THERE'S SOME
FEATURES OF THE CHEMISTRY OF
THAT METEORITE MAKE IT CLEAR
MARS IS MOST LIKELY PLACE OF
ORIGIN FOR IT, PROBABLY KNOCKED
OFF BY IMPACT PUTTING SOME
MATERIALS INTO BALLISTIC ORBIT
AND FOUND THEIR WAY TO EARTH.
THE CONTROVERSIAL PART IS
WHETHER THERE IS ANY REASON TO
CONSIDER BIOLOGY AS BEING
IMPORTANT IN THIS. I THINK MOST
PEOPLE WITH THE CONSPICUOUS
EXCEPTION PEOPLE WHO WROTE THE
PAPER IN THE FIRST PLACE SAY
AABOOTIOTIC PROCESSES ARE MORE
THAN SUFFICIENT TO EXPLAIN
EVERYTHING THAT WERE ORIGINALLY
DEDUCED TO BIOLOGY. SO AT
PRESENT LEVEL OF UNDERSTANDING
WE HAVE NO UNAMBIGUOUS OR
STRONGLY SUGGEST EVIDENCE FOR
LIFE ON MARS. WE CAN'T RULE OUT
IT MAY HAVE BEEN THERE. ONE
OTHER THING WEARING MY MARS HAT,
A VERY GOOD COLLEAGUE OF MINE AN
ATMOSPHERIC MODELER, I PUBLISHED
A PAPER LAST YEAR IN WHICH WE
LOOK AT THE RECORD OF TEMPERATE
ENVIRONMENTS AND WATER ON MARS
THROUGH TIME, AND EVERYONE WOULD
AGREE THAT MARS WAS ONCE WETTER
AND WARMER THAN IT IS NOW AND
THEN THROUGH TIME BASICALLY
BECAME THIS DECEM DESOLATE PLACE
TODAY. OUR MODELING STRONGLY
SUGGEST THAT IT WASN'T THE CASE
THAT MARS WAS CLIMATE FOR 600
MILLION YEARS THEN WENT SOUTH
BUT RATHER THAN BECAUSE MOST OF
THE WAY YOU GET WET WARM
ENVIRONMENTS ON MARS IS THROUGH
LARGE METEOR IMPACTS OR LARGE
VOLCANIC EVENTS SO WE THINK MARS
WAS WARM AN WET FOR MAYBE
100,000 YEARS, EVERY TEN MILLION
YEARS ACCORDING FOR THE FIRST
600 YEARS OF MARTIAN HISTORY.
THAT IS A MUCH LESS INVITING
SCENARIO FOR BIOLOGY. DOESN'T
RULE IT OUT BUT I THINK RIGHT
NOW WE ARE -- I'M STILL LOOKING
FOR EVIDENCE THAT WOULD MAKE ME
WANT TO BUY MORE STOCK IN MARS
BIOLOGY.
>> ONE OF THE PLAYERS IN THIS
DISCUSSION THAT HASN'T BEEN
MENTIONED, REALLY ASKS HOW DO
VIRUSES FIT INTO THIS
DISCUSSION? ARE WE MISSING
SOMETHING? WE CAN EFFECTS OF
BACTERIA OR VIRUSES OR BY
SOMETHING ELSE? WHAT ARE YOUR
COMMENTS ABOUT THAT?
>> NO, AGAIN, A GREAT QUESTION.
JUST AS ENVIRONMENTAL SEQUENCING
TAUGHT US WE WERE SUBSTANTIAL
IGNORANCE ABOUT THE DIVERSITY OF
BACTERIA THE LAST FEW DECADES
THERE IS MORE AND MORE
SEQUENCING OF VIRUSES, THERE
SOMETHING CALLED THE TARA
PROJECT RUN OUT OF FRANCE MOSTLY
WHICH HAS JUST TRANSFORMED OUR
UNDERSTANDING OF BIOLOGIC
DIVERSITY AND SURFACE OCEANS.
THEY FOUND SOMETHING LIKE
250,000 DISTINCT RNA VIRUSES
JUST TO THE UP PER HUNDRED
METERS OF THE OCEANS.S SO AGAIN
SUGGESTING THAT VIRUSES ARE
EVERYWHERE, I REMEMBER ONE
PERSON ESTIMATED SOMETHING LIKE
97% OF GENES IN THE OCEAN ARE
VIRAL. SO IN TERMS OF THE
ECOLOGY OF VIRUSES WE ARE JUST
STARTING TO LEARN ALL THINGS
THEY DO. AS SOME OF YOU MAY
KNOW, IN SCHOOL WE ALWAYS LEARN
VIRUSES HAVE THESE VERY SMALL
GENOMES BECAUSE THOSE VIRUSES
THAT WE KNOW ABOUT FROM DISEASES
TEND TO BE THAT WAY. BUT THERE
ARE VIRUSES THAT HAVE BEEN FOUND
IN THE LAST DECADE THAT HAVE
GENOMES LARGER THAN SMALL
BACTERIA. THERE ARE ONES THAT
HAVE EXAMPLE, THE ENTIRE GENE
CASSETTE FOR SYNTHETIC ELECTRON
TRANSFER, IT IS THOUGHT THESE
MAY HAVE THESE ESSENTIALLY TO
INCREASE METABOLIC PRODUCTIVITY
OF THEIR HOST. SO THEY CAN
ACTUALLY INCREASE THEIR OWN
NUMBERS FOR DISSEMINATION. WE
ARE ALSO FINDING VIRUSES ARE
VERY IMPORTANT IN THE ECOLOGY OF
PLANTS AND ANIMALS AND PROTUS IN
WAYS WE DON'T REALLY HELP SHAPE
ECOSYSTEM. SO IN TERMS OF JUST
DIVERSITY AND ECOLOGY, WE ARE
JUST ENTERING THIS WONDERFUL
EXCITING NEW WORLD UNDERSTANDING
WHAT VIRUSES DO AND NOT JUST THE
SMALL NUMBER OF VIRUSES THAT
HAVE INVOLVED IN DISEASE BUT
ASTOUNDINGLY GREATER DIVERSITY
OF VIRUSES THAT ARE INVOLVED IN
FUNCTIONING OF NATURAL ECO
SYSTEMS. THE OTHER PART OF THE
QUESTION, DO THEY FIT INTO THE
ORIGIN OF LIFE? I THINK YOU CAN
FIND PEOPLE WHO ARGUE THIS IN
DIFFERENT WAYS. IT IS CLEAR THAT
AT LEAST SOME VIRUSES ARE
RENEGADE GENES THAT ORIGINATED
IN ORGANISMS AND HAVE
ESSENTIALLY GONE OFF ON THEIR
OWN. THAT SAID I THINK PEOPLE
THAT HAD YOU BEEN AROUND A
BILLION YEARS AGO YOU WOULD HAVE
SEEN A LOT OF VIRUSES OR
INSIPIENT VIRUSES SO I THINK
THEY HAVE ALWAYS BEEN WITH US
BUT BY DEFINITION A VIRUS IS
DEPENDENT ON HOST CELL. FOR ITS
REPLICATION. SO IT IS HARD TO
THINK VIRUSES WERE CENTRAL TO
THE ORIGIN OF LIFE, COULD BE
WRONG ABOUT THAT. BUT I THINK
THEY HAVE PROBABLY FOR FOUR
BILLION YEARS BEEN IMPORTANT TO
THE EVOLUTION AND ECOLOGY OF
LIFE.
>> YOUR COMMENTS ALSO PERTAIN TO
SOMETHING LIKE BACTERIA PHAGO?
>> MY GUESS IS EVERY ORGANISM IS
ASSOCIATED WITH MUCH LARGER
DIVERSITY OF VIRUSES THAN WE
HAVE BEEN ABLE TO WORK OUT
THROUGH THE TRADITIONAL WAYS
THAT WE HAVE WORK WITH VIRUSES.
I DO HAVE SOME CONFIDENCE THAT
WHEN YOU GET A PHYSICAL 10 OR 15
YEARS FROM NOW THEY WILL TAKE A
STOOL SAMPLE AND LOOK AT YOUR
MICROBIOTA AND THAT WILL TELL
YOU MORE ABOUT THE STATE OF YOUR
HEALTH THAN THE PHYSICALS DUE
TODAY. WHETHER OR NOT WE WILL
KNOW ENOUGH ABOUT VIRUSES TO
INCORPORATE THEM INTO THAT KIND
OF PRACTICE, I DON'T KNOW.
>> ANDREW ASKS, OTHER THAN
PATHOGENICITY, WHAT DO YOU FEEL
IS THE STRONGEST SELECTIVE
PRESSURE THAT MICROBES EXERT ON
MULTI-CELLULAR LIFE?
>> THAT IS A GOOD QUESTION. I
THINK THEY EXERT A NUMBER OF
DIFFERENT TYPES. IN SOME WAYS
THEY USE ENVIRONMENTAL PRESSURES
BY DIFFERENT MICROBIAL
METABOLISMS. COMPETING FOR
NUTRIENTS. AGAIN THERE IS
PROBABLY PEOPLE IN THE AUDIENCE
MUCH MORE EXPERIMENTAL IN THIS
THAN I AM, BUT MY UNDERSTANDING
IS THE DEVELOPMENT OF YOUR
ADJUSTOR SYSTEM IS IN PART
GUIDED BY BACTERIA. BACTERIA
PLAY AN IMPORTANT ROLE IN THE
BREAK DOWN OF FOOD FOR
METABOLISM. I'M TOLD BACTERIA
ACTUALLY HELP TO TRAIN THE
IMMUNE SYSTEM. SO IN ESSENCE IF
THAT IS CORRECT, I THINK WILL
REASON TO BELIEVE THAT IT
SOMEHOW IS, BACTERIA PLAY AN
IMPORTANT ROLE IN JUST NORMAL
DEVELOPMENT AND FUNCTIONING OF
THE HUMAN ORGANISM. I THINK IT
IS VERY LIKELY THAT AS WE LEARN
MORE ABOUT THESE WE ARE FINDING
THAT THEY PLAY, MANY MORE
BACTERIA THAT PLAY THAT KIND OF
CONSTITUTIVE ROLE IN OUR HEALTH
AND THERE THERE ARE THAT PLAY A
ROLE IN PATHOGENICITY.
>> THE STUDIES OF THE TYPE THAT
YOU ARE DESCRIBING PROVIDE
INFORMATION ABOUT HOW THE
POSTULATED SPLIT BETWEEN
BACTERIA AND ARCHAEA TOOK PLACE?
>> ANOTHER GOOD QUESTION. I
DON'T THINK WE KNOW MUCH ABOUT
THAT TO BE HONEST. THERE ARE --
IF YOU JUST LOOK AT THE
MOLECULAR CHARACTERISTICS OF
BACTERIA AND ARCHEA, THERE ARE
OBVIOUSLY NUMBER OF THINGS THAT
GO BACK TO A COMMON ANCESTOR.
THINGS AS STRAIGHT FORWARD AS
CONTENT OF MEMBRANES, ARE
DISTINCT. UNFORTUNATELY WE HAVE
NO ORGANISMS THAT PRE-DATE THAT
DIVERGENCE BETWEEN THE TWO SO WE
CAN ONLY MAKE VERY BROAD
INFERENCES ABOUT WHETHER A
COMMON ANCESTOR WOULD HAVE
LOOKED LIKE. THERE ARE SOME
ECOLOGICAL DIFFERENCES THAT
MIGHT BE INFORMATIVE IN SOME
WAY. IT HAS BEEN SUGGESTED THAT
ARCHAEA ARE PARTICULARLY
SUCCESSFUL IN LOW ENERGY
ENVIRONMENTS. THEY ARE ABLE TO
SCAVENGE ENERGY EFFICIENTLY AND
MAINTAIN THEIR BIOLOGY WITH LOW
FLUXES OF ENERGY, MANY OF THEM
ARE. SO IT MAY BE THAT EARLY ON
TWO DIFFERENT GROUPS OF
ORGANISMS BECAME SUCCESSFUL AT
COLONIZING DISTINCTLY DIFFERENT
ENVIRONMENTS. THAT SAID, I DON'T
THINK WE KNOW A GREAT DEAL ABOUT
DIVERGENCE, THAT IS AN IMPORTANT
QUESTION. EVERY COUPLE OF YEARS,
I GO BACK AND REFURBISH MY
SLIDES ON PHYLOGENY AN EVERY
TIME THERE IS WHOLE MAJOR GROUPS
OF ARCHAEA. ASGARD ARCHEAA META
GENOMIC SEQUENCES IN 2015,
THERE'S AT LEAST TWO IN CULTURE
THESE ARE REALLY COOL. THEY
HAVE A NUMBER OF MOLECULAR
CHARACTERISTICS THAT 20 YEARS
AGO WE WOULD HAVE SAID WERE
UNIQUE TO EUKARYOTS AND SEEMED
TO BE PLAYING A ROLE IN THE
EMERGENCE OF EUKARYOTS. SO ONE
OF THE LESSONS THEY TAKE FROM
THAT IS THAT PARTICULARLY FOR
ARCHAEA AND ALSO BACTERIA, WILL
IS AN AWFUL LOT ABOUT THEIR
DIVERSITY THAN WE JUST DON'T YET
UNDERSTAND. IT IS POSSIBLE THAT
AS WE LEARN MORE ABOUT NATURAL
HISTORY OF BOTH GROUPS Z THAT
WILL SHED SOME LIGHT ON THE
QUESTION THAT WAS ASKED. FOR
NOW, I THINK WE ARE IN
SUBSTANTIAL IGNORANCE.
>> WHERE DO YOU THINK LIFE
STARTED? THERE SEEMS TO BE SORT
OF A GEOTHERMAL SCHOOL AND A
DEEP SEA VENT SCHOOL. IS THERE
COMPELLING EVIDENCE IN YOUR VIEW
FOR THESE OR ARE THEY STILL
LARGELY HYPOTHETICAL? AND WHAT
IS YOUR VIEW OF THAT?
>> AGAIN, IT IS A GOOD QUESTION,
WE KNOW THERE ARE CERTAIN TYPES
OF ENVIRONMENTS ASSOCIATED WITH
HYDRO THERMAL VENTS. WHERE IF
YOU CAN FIGURE OUT A WAY TO MAKE
A MEMBRANE LIKE SUBSTANCE YOU
WOULD GET A PH DIFFERENCE ON THE
TWO SIDES OF THAT THAT ALLOW YOU
TO BASICALLY TRANSPORT ELECTRONS
WHICH IS IN SOME WAYS AT THE
HEART OF ENERGY METABOLISM. WE
KNOW ALSO FROM EXPERIMENTAL
EVIDENCE IN SIMULATED
ENVIRONMENTS LIKE HYDRO THERMAL
VENTS, YOU CAN SYNTHESIZE AS I
MENTION SOME INTERMEDIATES IN
THE KREBS CYCLE. ON THE OTHER
HAND, THESE HOT ENVIRONMENTS
TEND TO BE PLACES WHERE
MOLECULES BREAK DOWN. THEY DON'T
HAVE LONG HALF LIVES.
THE ALTERNATIVE, WHICH IS I
THINK NOW MUCH DISCUSSED BY
PEOPLE LIKE JOHN SOUTHER LAND
FROM CAMBRIDGE AND OTHERS, IS
LAKES. BECAUSE LAKES HAVE THIS
INTERESTING CHARACTERISTIC OF
DRYING UP AND WETTING AGAIN SO
YOU CAN ACTUALLY DRIVE SOME
INTERESTING CHEMISTRY BY THAT
KIND OF CYCLING. LAKES AT LEAST
MINIMIZE PROBLEM OF DILUTION
WHICH IS A BIG PROBLEM IN THE
OCEANS. AGAIN, THERE ARE
CERTAIN TYPES OF CHEMISTRY
INCLUDING SOME OF THE RNA.
CHEMISTRY THAT HAS BEEN DONE IN
THE LABORATORY THAT MAKE SENSE
IN TERMS OF LAKE ENVIRONMENTS.
SO THERE ARE SOME ADVANTAGES TO
BOTH OF THESE. AND WHAT I FIND
INTERESTING THE GEOLOGISTS IN ME
IS THESE TWO GROUPS COME AFTER
EACH OTHER WITH HAMMERS AND
TONGS AND NONE OF THEM EVER STOP
TO THINK IF THEY GO TO ICELAND
THEY WOULD FIND WHERE THE MID
ATLANTIC RIDGE HYDRO THERMAL
RIDGE COMES UP ABOVE SEA LEVEL
AND IS COVERED BY LAKES. SO I
THINK IN THE REAL WORLD, THESE
ARE NOT MUTUALLY EXCLUSIVE
HYPOTHESES THAT THEIR PRO POINTS
MAKE THEM OUT -- PROPONENTS MAKE
THEM OUT TO BE.
>> APROPOS OF DISCUSSION OF
VIRUS WE HAVE A QUESTION FROM
BOB WHO ASKS WHETHER VIRUSES
MEET YOUR DEFINITION OF LIFE. A
CHEMICAL UNSUSTAINING SYSTEM
CAPABLE OF DARWINIAN EVOLUTION.
>> WELL, THEY COME CLOSE. I KNOW
A LOT OF PEOPLE DON'T LIKE TO
THINK OF THEM AS LIFE BECAUSE
THEY DON'T METABOLIZE, THEY
DON'T DO ALL SORTS OF THINGS
MOST LIFE DOES. THEY ARE CLEARLY
SUBJECT TO DARWINIAN EVOLUTION.
IN THAT -- THAT IS A VOTE FOR
LIFE. THEY ARE NOT
SELF-SUSTAINING. WHICH I GUESS A
VOTE AGAINST IT. . I DON'T GET
TERRIBLY EXCITED ABOUT THE
DEBATE OF WHETHER VIRUSES ARE OR
ARE NOT LIVING BECAUSE THEY
CERTAINLY ARE INTIMATELY
CONNECTED TO LIFE IN TERMS OF
BOTH FUNCTION AND EVOLUTION.
>> SOMEWHAT RELATED TO THAT,
TARIN ASKS IS THERE ANY EVIDENCE
FOR UNIQUE BIOMOLECULES FOR
EXAMPLE DNA, RNA, SOMETHING LIKE
THAT, HYBRID, OR PROTEINS, DO WE
HAVE ANY EVIDENCE OF THE
BIOMOLECULES THAT ARE MADE
DURING THE EARLY TIME PERIODS OF
LIFE HISTORY? IS THERE ANY
TECHNOLOGY THAT PERMITS SOME
UNDERSTANDING OF WHAT THOSE
MOLECULES ARE?
>> NO. ONE OF THE ISSUES OF THE
GEOLOGIC RECORD IS THAT
SEDIMENTARY ROCKS DEPOSITED
THROUGH TIME CREATE AND PRESERVE
A RECORD OF LIFE AND
ENVIRONMENTS WHEN AND WHERE THEY
FORM. BUT EROSION IS AN ERASER.
ONCE YOU GET BACK 4, 3 1/2
MILLION YEARS AGO THERE IS VERY
LITTLE RECORD OF SEDIMENTARY
ROCKS. THE OLDEST AREKS THAT WE
KNOW OF -- OLDEST ROCKS ARE
HIGHLY ME THATMORPHOSIS A
MILLION YEARS OLDS. WE HAVE
OLDER MINERALS ONE CALLED
ZIRCON, THE GEOLOGIST FRIEND
BECAUSE ZIRCON'S -- IT IS --
THERE IS ZIRCONIUM SILICATED.
THEY ACTUALLY INCORPORATE
URANIUM INTO CRYSTAL LATTICES
BUT DON'T INCORPORATE LEAD.
SOME OF THAT URANIUM IS RADIO
ACTIVE AND GIVES RISE TO RADIO
GENIC LEAD WHICH STAYS IN THE
CRYSTAL LATTICE. SO THOSE ARE
ACTUALLY THE BEST MATERIALS FOR
RADIO METRIC DATING.
INTERESTINGLY ENOUGH IF YOU GO
TO THE NORTHS SHORE OF BOSTON
TODAY AN COLLECT A BUCKET FULL
OF SAND, THERE WILL BE A NUMBER
OF ZIRCON CRYSTALS THERE THAT
FORMED IN GRANITES THAT MADE THE
WHITE MOUNTAINS IN NEW HAMPSHIRE
AND TRANSPORTED DOWN TO THE
SEASHORE BY EROSION. AND ARE
JUST NOW -- THEY ARE 400
MILLION-YEAR-OLD ZIRCONS SITTING
IN P MODERNIZED.
S. WE DO HAVE EXAMPLES OF
ZIRCONS MORE THAN 4 BILLION
YEARS OLD THAT ARE IN
3.6 BILLION-YEAR-OLD SAND STONES
SO WE GET CLUES TO THE EARLY
EARTH BUT NOTHING TO PRESERVE
THE TYPE OF MOLECULES THAT ARE
BEING ASKED ABOUT. SO ALL OUR
INFERENCES ABOUT THE TYPES OF
MOLECULES THAT COULD HAVE BEEN
AND PROBABLY WERE MADE BY A
BIOLOGICAL PROCESSES COME FROM
ONE OF TWO SOURCES. ONE,
EXPERIMENTS. EVER SINCE MILLER
AND URI THERE'S BEEN COTTAGE
INDUSTRY OF PEOPLE DOING
PREBIOTIC CHEMISTRY. THAT HAS
BEEN VERY SUCCESSFUL IN SOME
WAYS IN SHOWING THAT WE CAN
EXPECT AMINO ACIDS, LIPIDS, EVEN
SHORT OLIGOMERS OF NUCLEIC
ACIDS. TO HAVE EXISTED AND OF
COURSE THE OTHER EVIDENCE IS
CERTAIN METEORITES. THESE
CARBONATION CHONDRITES SOME HAVE
70 DIFFERENT AMINO ACIDS IN THEM
SO WE KNOW THIS TYPE OF
CHEMISTRY, GOES ON AND ACTUALLY
GOES ON FAIRLY LONGLY, IN THE
EARLY HISTORY OF SULFUR SYSTEMS.
SO THAT IS EVERYTHING WE KNOW
COMES FROM THOSE AND NONE
BASICALLY COMES FROM A WELL
PRESERVED GEOLOGIC RECORD OF THE
FIRST 500 MILLION YEARS HISTORY.
>> I BELIEVE IS IT TRUE THAT
RADIO ICE TOPIC DECAY --
ISOTOPIC DECAY IN ZIRCON IS A
TOOL FOR DETERMINING THE AGE AT
LEAST ZIRCON, THE ROCK. CAN YOU
EXPLAIN WHETHER A ZIRCON IS? NOT
SURE ALL OF US UNDERSTAND THAT.
>> WELL IT IS A MINERAL. IF YOU
HAVE JEWELRY MADE OF CUBIC
ZIRCONIUM, THAT IS INDUSTRIALLY
MADE ZIRCONS USED IN THE JEWELRY
INDUSTRY. BUT IT IS BASICALLY
PARTICULARLY IN ROCKS LIKE
GRANITE, THOUGH NOT EXCLUSIVELY.
DIFFERENT ELEMENTS ARE
INCORPORATED INTO DIFFERENT
MINERALS UNDER DIFFERENT
CONDITIONS OF TEMPERATURE AND
PRESSURE. SOME ELEMENTS ARE NOT
EASILY INCORPORATED INTO ROCK
FORMING MINERALS SO THEY ARE
ONLY TAKEN INTO MINERAL LATTICES
FAIRLY LATE IN THE HISTORY OF A
MAGMA. ONE OF THOSE IS ZIRCONIUM
WHICH THEN REACTS WITH SILICA
AND FOR OXYGEN TO MAKE A
MINERAL. I CONSIDERED ZIRCONIUM
TO BE THE GEOLOGIST EQUIVALENT
OF THE FLIGHT RECORDERS, WHEN AN
AIRPLANE GOES DOWN IT IS FLIGHT
RECORDER IS TOUGH ENOUGH THAT IT
RESISTS DESTRUCTION AND TELLS
YOU A LOT ABOUT WHAT HAPPENED.
AND ZIRCONS ARE VERY HARD TO
RECRYSTALLIZE, VERY HARD FOR
FLUIDS TO PERCOLATE THROUGH THEM
AND CHANGE THEIR CHEMISTRY.
BECAUSE THEY INCORPORATE URANIUM
WHICH HAS TWO DIFFERENT RADIO
ACTIVE ISOTOPE, THEY ARE VERY,
VERY GOOD FOR DETERMINING AGES
WHEN THOSE CRYSTALS FORMED. SO
WE HAVE DONE WORK IN MY OWN WORK
WHERE WE HAVE COLLECTED VOLCANIC
ASHES THAT WERE INNER LAYERED
WITH SEDIMENTS THAT HAVE FOSSILS
AND ENVIRONMENTAL CLUES IN THEM
AND THE ZIRCON IN THOSE ASHES
PROVIDE A PRECISE DATE FOR AL
THE THINGS WE ARE SEEING. SO
BASICALLY IT IS MINERALS THAT
INCORPORATE RADIO ACTIVE
ISOTOPES AND THOSE RADIO ACTIVE
ISOTOPES DECAY AT RATES THAT CAN
BE MEASURED MANY THE LABORATORY
AND THEREFORE CAN BE USED TO
TELL AGE OF ROCKS. .
>> IS IT STILL FELT GENERALLY
SPEAKING THE OLDEST ROCKS ON
EARTH ARE SOMETHING LIKE ABOUT 4
BILLION YEARS AND THE MOON ROCKS
ARE ABOUT THE SAME? IS THAT
STILL -- IS THAT THE STATE AT
PRESENT?
>> YEAH. ON EARTH YOU ARE
EXACTLY RIGHT. THERE IS VERY
HIGHLY METAMORPHOSED ROCKS IN
NORTHERN CANADA WHICH HAVE BEEN
DATED WITH ZIRCONS AT A SHADE
OVER 4 BILLION YEARS. AS YOU GO
BACK FURTHER IN TIME, EROSION
TENDS TO GET AND ME FA MORPHISM
TAKES UPPER HAND OVER UPPER
FORMATION SO WE DON'T HAVE A
GOOD RECORD OF ALMOST THE FIRST
BILLION YEARS OF EARTH HISTORY.
THE MOON HAS SOME PEOPLE IN THE
AUDIENCE WILL PROBABLY KNOW IS
THOUGHT TO ORIGINATED FROM
BOMBARDMENT EARLY IN THE
FORMATION HISTORY OF THE EARTH.
WHEN THEETH WAS ALMOST FULLY
FORMED, IT WAS CLOBBERED BY A
MARS SIZE STRUCTURE. THAT
BASICALLY EJECTED A LOTS OF
MATERIAL INTO SPACE BUT BECAUSE
OF GRAVITY, MUCH OF IT STAYED IN
EARTH'S ORBIT AND WAS
RECONSTITUTED AS THE MOON. SO WE
DO HAVE SOME VERY OLD MATERIALS,
4 BILLION YEARS PLUS MATERIALS
ON THE MOON, FAMOUSLY, APOLLO
ASTRONAUTS CHECKED LUNAR SAMPLE
SEVERAL PARTS OF THE MOON AND
WHEN THEY DATED THEM THEY CAME
AFTER 3.9 BILLION YEARS. T THAT
WAS USED TO ARGUE FOR WHAT HAS
BEEN CALLED LATE HEAVY
BOMBARDMENT, THE IDEA THAT ABOUT
3.9 BILLION YEARS AGO PERHAPS BY
JUPITER AND SATURN COMING IN TO
ORBITAL RESIDENCE, A LOT OF
MATERIAL FROM THE SOLAR SYSTEM,
OUTER SOLAR SYSTEM WAS EJECTED
INTO THE INNER SOLAR SYSTEM AND
THERE IS THIS MAJOR FLUX OF
METEORITES ON TO THE INNER PART
OF THE SOLAR SYSTEM. IT IS NOW
PRETTY CLEAR THAT ALL OF THOSE
MATERIALS COLLECTED ON THE MOON
CAME FROM A SINGLE LARGE IMPACT
AND SO WHILE IT IS POSSIBLE
THERE WAS SOME BOMBARDMENT STAGE
OF THE TYPE BEING TALKED ABOUT,
BUT IF THERE WAS IT MIGHT HAVE
HAPPENED 4.4 BILLION YEARS AGO
RATHER THAN LATER. IT IS A
COMPLICATED PICTURE.
>> I GATHER. WE HAVE AN
INTERESTING QUESTION FROM
MICHAEL. WHO SAYS THE IDEA OF
DEEP SEA HYDRO THERMAL VENTS WAS
PUT FORWARD TO SHIELD EARLY LIFE
FROM ULTRAVIOLET DAMAGE. SO A
GREAT QUESTION IS WHETHER
ULTRAVIOLET WAS REALLY DAMAGING
OR COULD BE USED AS A SOURCE OF
ENERGY FOR A PREBIOTIC
CHEMISTRY.
>> GREAT QUESTION. PEOPLE HAVE
USED VARIOUS TYPES OF RADIATION
AS SOURCES FOR ENERGY SOURCES
FOR CHEMISTRY. SO IN THAT REGARD
I THINK ULTRAVIOLET MAY WELL
HAVE BEEN PART OF THE MIXTURE OF
ENERGY SOURCES FOR DRIVING
PREBIOTIC REACTIONS. THE OTHER
THING OF COURSE IS THAT WHEN I
WAS A STUDENT PEOPLE WERE VERY
WORRIED THAT SINCE THERE WAS NO
OXYGEN ON THE EARLY EARTH THERE
WOULDN'T HAVE BEEN AN OZONE
SHIELD THE WAY THERE IS TODAY.
SO THEREFORE HOW COULD LIFE GET
GOING. THEN PEOPLE FOUND OUTUP
ABOUT A MILLIMETER OF SAND
GRAINS IS A PRETTY EFFECTIVE
SHIELD AGAINST TYPES OF UV THAT
DESTROY MOLECULES. COUPLE OF
METERS OF WATER WILL DO IT. AS
SOME PEOPLE LISTENING MAY WELL
KNOW, A LOT OF MICROBES ARE VERY
VERY GOOD ABOUT DNA REPAIR.
THERE IS A BACTERIA CALLED
DINACOCCUS FOUND INSIDE WALLS OF
NUCLEAR REACTORS SO EVEN IF YOU
HAVE DESTRUCTIVE UV, BACTERIA
AND ARCHEA HAVE RATHER MARKEDLY
SOPHISTICATED WAYS OF MAKING
REPAIRS. SO YES, I THINK -- I
THINK TO BE ACTUALLY IN TERMS OF
HISTORY, IT WAS ONLY IN THE
1970s THE PEOPLE STARTED
LOOKING AT MID OCEAN RIDGES AND
FINDING THAT THEY WERE PLACES OF
HIGH BIOLOGICAL DIVERSITY IN THE
MIDDLE OF THE OCEAN OF THE THAT
WAS ACTUALLY TRANSFORMATIVE. I
THINK THAT IN SOME WAYS ALSO
FUELED THE IDEA THAT NOT ONLY
WERE MID OCEAN RIDGES
BIOLOGICALLY IMPORTANT BUT COULD
BE PRE-BIOLOGICALLY IMPORTANT. I
DON'T DISPUTE THAT INFERENCE AT
ALL. I JUST THINK ONE CAN ONLY
PLAY THE UV CARD SO STRONGLY AND
AS THE QUESTION IMPLIED, ON THE
PREBIOTIC EARTH YOU CAN UV MAY
HAVE BEEN YOUR FRIEND IN TERMS
OF DRIVING PREBIOTIC REACTIONS.
>> I THINK THAT YOGI BERRA, IT'S
GREAT CREDIT FOR A STATEMENT
THAT I BELIEVE WAS REALLY MADE
BY NEIL SPORE. THAT IS, IT IS
DIFFICULT TO PREDICT THINGS
PARTICULARLY ABOUT THE FUTURE.
BUT BUNCH OF QUESTIONS THAT ASKS
YOUR OPINION ABOUT THE FUTURE.
IF YOU DON'T MIND WE CAN
CONSIDER SOME OF THOSE.
>> SURE.
>> DO YOU THINK THAT (INAUDIBLE)
LIFE IS FREQUENT OR RARE IN THE
UNIVERSE?
>> IT IS INTERESTING. I ALWAYS
THINK -- IT IS A QUESTION THAT
WE CAN ALL ASK AND I THINK OF
TWO BOOKS THAT WERE PUBLISHED
COUPLE OF DECADES AGO. ONE WAS
BY WARREN BROWNLY CALLED RARE
EARTH. THEY CONCLUDED THAT LIFE
WAS PROBABLY REPLETE IN THE
UNIVERSE BUT IT WAS ALMOST
ALWAYS MICROBIAL AND THAT
COMPLEX TECHNOLOGICAL LIFE WAS
RARE. SOME YEARS LATER SIMON CON
WAY MORRIS, A PALEONTOLOGIST IN
CAMBRIDGE WHO WROTE A BOOK IN
WHICH HE SAID WELL, VERY, VERY
HARD TO MAKE LIFE, THEREFORE
LIFE MUST BE RARE IN THE
UNIVERSE. BUT ONCE YOU GET LIFE
INTELLIGENCE IS ALMOST
INEVITABLE. WHAT IS INTERESTING
ABOUT THIS IS THEY BOTH HAD
RECOURSE TO EXACTLY THE SAME
FACTUAL INFORMATION WHICH IS
THAT LIFE EXISTS ON EARTH. THAT
IS -- IN A FACTUAL SENSE ALL WE
KNOW ABOUT LIFE. MOST PEOPLE
THAT I KNOW AND WORK WITH, THINK
THAT IT IS LIKELY THAT LIFE
EXISTS ELSEWHERE IN THE
UNIVERSE, THAT IN SOME WAYS IF
EARTH WERE A SINGULARITY, THAT
WOULD BE ALMOST HARDER TO
CONTEMPLATE THAN THE IDEA THAT
LIFE IS OUT THERE. HAVING SAID
THAT, IT IS COMPLETE SPECULATION
WHAT KIND OF LIFE MAY EXIST IN
WHAT QUANTITIES DIMENSIONS IN
OTHER PLACES. PARTS OF THE
PROBLEM IS THE WAY WE LOOK FOR
LIFE BEYOND THE EARTH. OUR OWN
SOLAR SYSTEM WE CAN GO THERE. WE
HAVE BEEN TO MARS. WE ARE
PROBABLY GOING TO SEND
INTERESTING MISSIONS TO PLACES
MOONS OF OUTER PLANETS LIKE IN
TITAN WHICH ARE POSSIBILITIES
FOR LIFE AS WE. THERE E AT
LEAST WE CAN GO AND WE CAN DO
EXPERIMENTS AN COLLECT SAMPLES.
AND ANSWER MORE DEFINITIVELY
WHETHER LIFE IS PRESENT IN THE
CASE OF MARSES WHETHER IT MIGHT
HAVE BEEN PRESENT IN THE PAST.
THAT BECOMES HARD ONCE YOU GET
BEYOND OUR OWN SOLAR SYSTEM. SO
IN OUR OWN GALACTIC
NEIGHBORHOOD, COUPLE OF TENS OF
LIGHT YEARS, WE DEVELOPED THE
CAPACITY TO LOOK AT COMPOSITION
OF ATMOSPHERES. AND THERE IS A
DEBATE TO WHETHER ANY
ATMOSPHERIC COMPOSITION IS
ACTUALLY DIAGNOSTIC FOR LIFE BUT
IF WE ARE GOING TO FIND EVIDENCE
OF LIFE IN THOSE PLANETS THE
MOST LIKELY WAY TO LOOK FOR IT
IS ON THE BASIS OF WHAT IT DOES
TO THE ENVIRONMENT. THEN FOR
MOST OF THE UNIVERSE WE ARE ONLY
GOING TO KNOW IF SOMEBODY TELLS
US BECAUSE WE JUST DON'T HAVE
THE CAPACITY TO DO THINGS LIKE
EITHER GO THERE OR LOOK AT THAT
ENVIRONMENT. SO IT IS A GREAT
QUESTION. I THINK A LOT OF THE
BEST WRITING ON THE
POSSIBILITIES OF LIFE AND I SAY
THIS IN ALL SERIOUSNESS IS
SCIENCE FICTION AND NOT
SCIENTIFIC LITERATURE. I THINK
WHAT (INAUDIBLE) THINKS ABOUT
WHEN HE THINKS ABOUT ET IS ABOUT
AS VALID AS WHAT I THINK ABOUT
WHEN I THINK ABOUT LOOKING FOR
LIFE ON MARS. STEVEN STEELBURG.
>> IT IS INTERESTING, SEEMS TO
ME IT WASN'T SO VERY LONG AGO
THESE QUESTIONS LIKE THE KINDS
WE ARE TALKING ABOUT, WE ARE
LIMBED TO SCIENCE FICTION
WRITERS AND TO CARTOON STRIPS,
(INAUDIBLE) WHICH BRINGS UP AN
INTERESTING QUESTION ABOUT IN
THE PAST HALF CENTURY, WHAT IS
YOUR TAKE ON HOW SORT OF PUBLIC
AND THE SCIENCE ATTITUDES VIEW
OFS ABOUT THE ORIGIN OF LIFE
HAVE CHANGED?
>> BOY, THAT IS AN INTERESTING
QUESTION. MY GUESS IS THAT OVER
THE PAST 50 YEARS RATHER THAN
THERE BEING SOME STRONG
BACTERIAL SHIFT IN THE ORBIT AS
A WHOLE, I GUESS THE DIVISION
BETWEEN PEOPLE WHO ARE INTENT TO
THINK LIFE IN SOME WAY
ORIGINATED BY NATURAL CAUSES, BY
THOSE WHO THINKS IT WAS DIVINE
INSPIRATION. I DO GET THE
FEELING THAT -- THOSE WHO DOUBT
PHYSICAL PROCESSES FROM THE
ORIGINS OF LIFE TEND TO BE THE
SAME PEOPLE WHO ARE NOT
CONVINCED THAT THERE IS A THING
CALLED EVOLUTIO EVOLUTION COMESM
CONSERVATIVE ELEMENTS NOT JUST
IN ISLAM AND CHRISTIANITY AND
THINGS LIKE THIS, WHEREAS OTHER
PORTIONS OF THE POPULATION ARE
QUITE HAPPY TO THINK THAT
EVOLUTION IS A THING, IT HAPPENS
WE CAN OBSERVE IT WE CAN MODEL
IT WE CAN DO IT EXPERIMENTALLY
AND SO THEREFORE, EVEN IF WE
DON'T UNDERSTAND HOW LIFE
ORIGINATED, THAT THERE IS REASON
TO BELIEVE THAT THERE ARE
PHYSICAL CAUSES THAT LEAD TO
THAT. I GUESS WHAT HAS CHANGED
MORE THAN ANYTHING AND MAYBE
THIS WHERE THE QUESTION COMES
FROM, IS THAT 50 YEARS AGO, IF
WE THOUGHT DID LIFE BEGIN ON
MARS, ISAAC OR RAY BRAD BURY ARE
THE PEOPLE YOU WOULD LOOK TO.
NOW, WE HAVE BEEN THERE. WE
ACTUALLY CAN CONSTRAIN ISSUES
MUCH, MUCH MORE THAN WE COULD
THEN. THAT DOES GIVE RISE TO AT
LEAST THE FEELING THAT THROUGH
THE REMARKABLE PROGRESS WE HAVE
MADE IN OBSERVATION,S NOT JUST
SOLAR SYSTEM THE UNIVERSE, I
HAVE HUGE ADMONITION (INAUDIBLE)
POSSIBLE. THEN THAT I THINK DOES
GIVE RISE TO THE SORT OF THING
THAT PERSON IS A NATURAL SYSTEM
AND IT OPERATES UNDER NATURAL
LAWS. I THINK THAT IS ABOUT THE
BEST APPROACH TO AND ADVANCE
ANSWER I CAN GIVE.
>> IN YOUR POSITION AS A LEADING
ACADEMIC GEOLOGIST BIOLOGIST,
AND ALSO INVOLVED WITH NASA AND
OTHER ORGANIZATIONS AND GROUPS,
DO YOU HAVE A FEELING AS TO
WHETHER THE KINDS OF QUESTIONS
YOU ARE INTERESTED IN ARE MORE
LIKELY TO BE ANSWERED BY MANNED
EXPLORATION OR BY UNMANNED
EXPLORATION? ROBOTICS AND
TELESCOPES IN SPACE?
>> YEAH, WELL I THINK UNTIL WE
FIGURE OUT HOW TO BREAK THE LAWS
OF PHYSICS AND GETTING TO SEE
THE SPEED OF LIGHT, IN OUR SOLAR
SYSTEM, THAT IS THE ONLY PLACE
HUMANS ARE GOING TO SEND BUT ON
-- THIS DEBATE GOES ON ALL THE
TIME FOR MARS. I ACTUALLY HAVE
FRIENDS WHO WOULD VOLUNTEER IN
AN INSTANT TO BE PART OF THE
FIRST HUMAN EXPEDITION TO MARS
EVEN IF IT WERE CERTAIN THEY
WOULD NEVER COME BACK. AS ONE OF
MY FRIENDS SAID, IT'S MARS MAN.
NOW, I'M -- I THINK I WOULD
RATHER SIT IN MY OFFICE AND HAVE
A CUP OF COFFEE AND WATCH THAT
FROM A DISTANCE. BUT I THINK
THERE IS ACTUALLY A PRACTICAL
QUESTION IN THAT TO BE HONEST, I
THINK THE MAJOR REASON TO HAVE
HUMAN FOOTPRINTS ON MARS IS KIND
OF A SOLAR SYSTEM MANIFEST
DESTINY TO SAY WE HAVE DONE IT
AND CAN PUT THE FLAG IN THERE.
BECAUSE A, IF WE REALLY START
WORKING ON THIS, VERY HARD
TODAY, IT WOULD BE 20 YEARS
BEFORE A HUMAN WOULD SET FOOT ON
MARS AND THERE WOULDN'T BE MUCH
CHANGE FROM YOUR TRILLION DOLLAR
BILL. WITHIN THAT 20 YEARS THE
SOPHISTICATION OF ROBOTIC
INSTRUMENTS WILL BE SUCH THAT I
HI THE SCIENTIFIC REASONS TO PUT
A HUMAN ON MARS WILL BE MUCH
DIMINISHED AND IT HAS TO BE THIS
EXPLORATION FOR EXPLORATIONS
SAKE. HAVING SAID THAT, IT IS
WORTH RECOUNTING A STORY FROM
WHEN WE WERE FIRST DOING
PRACTICE MISSIONS FOR THE MARS
ROVER YEARS AGO AND WE HAD MOCK
ROVERS IN DEATH VALLEY AND STEVE
SQUIRE THE CHIEF SCIENTIST AND I
WERE ON WALK ONE DAY, I LOOKED
AT A ROCK PICKED IT UP AND
WHACKED IT WITH MY GEOLOGIC
HAMMER, TOOK LOOK AT IT THROUGH
IT AWAY. WHEN I CAME BACK STEVE
HAD HIS STOPWATCH OUT AND HE
SAID THAT TOOK YOU TWO MINUTES,
ON MARS THAT WOULD TAKE YOU A
WEEK. AND THERE IS THAT SENSE OF
REAL TIME INTERPRETATION THAT
HUMANS COULD DO. BUT AGAIN, I
THINK THAT THE DIFFERENCE
BETWEEN HUMAN AND ROBOTIC
INVESTIGATIONS IN TERMS OF
ACTUAL TIME, IS DIMINISHED
THROUGH TIME, AND WITH THE
ROBOTS GETTING BETTER AND BETTER
AT DOING THE THINGS THAT WE DO.
AND SURE THAT THERE ARE
ENGINEERS WORKING HOW ARTIFICIAL
INTELLIGENCE CAN FURTHER ALLOW
DECISION MAKING BY ROBOTS. SO WE
WILL SEE. I DON'T KNOW WHAT THE
FUTURE BRINGS. I'M FINE WITH
YOGI BERRA, I THINK YOU ARE
RIGHT. IF BERRA EVER READ NEIL
SPORE.
>> WE ONLY HAVE TIME FOR TWO
QUESTIONS. I HAVE ONE LAST ONE
TO ASK YOU. SO I'M GOING TO SAVE
THAT BUT QUICK QUESTION. MOST
WRITING ABOUT LIFE ON EARTH
BEGIN BUSINESS TALKING ABOUT THE
FAMOUS MIRROR EXPERIMENT IN THE
1950s. IS THAT EXPERIMENT EVER
BEEN REPEATED, NOT IN TERMS OF
ITS VALIDITY BUT IN TERMS OF
EXPANDING IT, OF WHAT COMES
NEXT. HAS THAT OR IS THAT JUST
MAYBE THERE'S NO FUNDING FOR, I
DON'T KNOW, WHAT IS THE
SITUATION FOR THAT?
>> THERE IS ACTUALLY SMALL
VIBRANT COMMUNITY PEOPLE WHO DO
EXPERIMENTS VERSUS STANLEY
MILLER THEMSELVES, IN YEARS
FOLLOWING THE MILLER EXPERIMENT
DID ACTUALLY VARY THE RECIPE FOR
THE EXPERIMENT, SAW HOW YIELDS
AND THINGS LIKE THAT VARIED SO
STANLEY DID A LOT OF WORK BUT
MANY OTHER PEOPLE HAVE DONE
ENOUGH WORK THAT AT THIS POINTS
I THINK MOST PEOPLE ARE CONTENT
TO THINK BIOLOGICALLY IMPORTANT
MONOMERS CAN BE MADE BY PHYSICAL
PROCESSES. THERE IS ALSO A LOT
OF WORK ON TRYING TO CONDENSE
THOSE MONOMERS SO YOU CAN MAKE
FOLLOWERS AND THAT HAS CERTAIN
CONSTRAINTS BUT REASONABLY
SUCCESSFUL PEOPLE LIKE LESLIE
DID INTERESTING WORK ON
REPLICATING NUCLEIC ACID MON
MORES HOG GOMERICALLY. THERE IS
A -- OLIGOMERICALLY. THERE'S A
FAIR AMOUNT OF WORK ON THAT. AND
IT ALL LEADS IN THE DIRECTION OF
PLAUSIBILITY.
>> PERMIT ME TO ASK THE LAST
QUESTIQUESTION. YOU COMMENTED AT
THE CHANGES IN ATTITUDE AND
UNDERSTANDING OF THE PAST 50
YEARS. NOW THE QUESTION IS, IN
THE NEXT 50 YEARS WHAT DO YOU
THINK OUR GRANDCHILDREN WILL
KNOW ABOUT THE ORIGIN OF LIFE?
>> AGAIN, ONE CAN ONLY
SPECULATE. I SHOULD SAY THAT
ALTHOUGH SOME WAYS MILLER YUI
AND THE AGE OF PLANETARY
EXPLORATION THINKING ABOUT
ORIGIN OF LIFE OR LIFE TO
UNIVERSE, THE LAST 70, 80ERS
YEW, IF YOU GO BACK TO PARADISE
LOST,S JOHN MILTEN HAS A
QUATRAINE ABOUT MOUNTAINS
VALLEYS RIVERS AN LIFE ON OTHER
PLANETS BECAUSE G A ALELEO
LANDED IN MILTON CORRESPONDED
WITH Q GALILEO. SO THE
EXPECTATION IN THOSE DAY, THERE
ARE OTHER PLANETS OUT THERE,
THEY ARE LIKE US, THEY PROBABLY
HAVE LIFE, WHAT IS THE BIG DEAL?
IT WAS ONLY IN THE 19TH CENTURY
LOOKING MORE CLOSELY AND SAW
THAT MARS WAS A PRETTY DECEMBER
LATE PLACE THAT ENTHUSIASM AT
LEAST FOR LIFE BEYOND THE EARTH
DECLINED, BUT NOW WITH THE
CURRENT AGE OF EXPLORATION, IT'S
COME BACK AGAIN SO I IMAGINE
THAT MANY OF THE QUESTIONS WHERE
I HAD TO TRUTHFULLY ANSWER AND
SAY WE DON'T KNOW, WILL BE
CLOSER TO CLOSER TO DEFINITIVE
EXPLANATION 50 YEARS FROM NOW,
WE WILL KNOW WHETHER OR NOT
THERE'S BEEN LIFE IN ANOTHER
SOLAR SYSTEM. WE MAY OR MAY NOT
KNOW WHETHER THERE'S INTELLIGENT
LIFE OUT THERE. BECAUSE IT MAY
OR MY NOT BE OUT THERE. I THINK
WE WILL KNOW A LOT MORE ABOUT
THE PROCESSES THAT NOT ONLY GIVE
RISE TO INFORMATION BUT ALSO
GIVE RISE TO PROTEINS AND
FUNCTION. AND I'M ACTUALLY
FAIRLY CONFIDENTNA WE WILL HAVE
A REASONABLE UNDERSTANDING OF
HOW THOSE TWO TYPES OF SYSTEMS
INTEGRATE. THERE'S ALREADY SOME
INTERESTING WORK WHERE PEOPLE
ARE STARTING TO LOOK AT, NOT SO
MUCH AT THE PART OF ENZYME BUT
THE CO-FACTORS. AND THAT MAY
ACTUALLY OPEN UP A INTERESTING
BRIDGE BETWEEN THESE TWO
DIFFERENT WAYS OF THINKING ABOUT
THE ORIGIN OF LIFE. I WON'T BE
HERE SO WE WILL SE SEE.
>> WE SHOULD ALL BE AROUND THE
NEXT 50 YEARS TO FIND OUT.
THAT'S PROBABLY -- I
(OVERLAPPING SPEAKERS)
>> AT LEAST IN MY MIND TIES
WHICH YOU ARE TALKING ABOUT IN
WITH RESPECT TO MEDICINE AND
HEALTH AND ALL, THAT IS OF
COURSE, THIS HUMAN MICROBIOME
WHICH IS HOME TO BACTERIA
ARCHAEA VIRUSES FUN GUY,
PARASITES, I GUESS IT IS A BIG
STRETCH TO PUT THAT IN TO
GEOLOGIC TERMS BUT MAYBE THERE
ARE SOME RELATIONSHIPS IN TERMS
OF WHAT YOU LEARN ABOUT HOW
BACTERIA REACTING WITH GEOLOGIC
FEATURES CHANGE OR HAS SOMETHING
TO DO WITH THE ELUTION OF LIFE
AND CHANGE IN FORM. SO WE ARE
NOT ONLY OUT OF THAT REALM.
>> NOT AT ALL.
>> SO LISTEN, I'M SURE THERE ARE
HUNDREDS AND HUNDREDS, I DON'T
KNOW THOUSANDS OF PEOPLE WHO
HAVE WATCHED YOUR PRESENTATION
TODAY. HALF OF THEM AND ALL OF
ON BEHALF OF THEM AND ALL OF US,
WE REALLY THANK Y THANK YOU. THS
BEEN A VERY EXCITING AND
PROVOCATIVE, I THINK IT IS
ANOTHER EXAMPLE THAT BRIDGING
FROM CLASSICAL CLINICAL MEDICINE
IN TO DISCIPLINES SUCH AS YOURS,
IS NOT AS FARFETCHED AS ONE
MAKES BECAUSE WE ARE ALL
CONFRONTING THE SAME BIG
BIOLOGICAL QUESTIONS ABOUT LIFE,
ABOUT EVOLUTION, ABOUT
ADAPTATION. THESE ARE THINGS
IMPORTANT TO KNOW. SO THANK YOU,
THANK YOU VERY, VERY MUCH. WE
HOPE SOME DAY YOU WILL COME
VISIT THE NIH AND IT WOULD BE A
PLEASURE.
>> THANK YOU AGAIN FOR INVITING
ME AND FOR EVERYBODY THAT ASKED
QUESTIONS. THIS WAS ACTUALLY A
LOT OF FUN. I APPRECIATE IT.