Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Summer 2006 Workshop in Biology and Multimedia for High School Teachers

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. HISTORY OF LIFE Beth Mick - Lesson Plan How Much Is a Billion? Author: Anne Monk rch_lessons.php?sort_by=audi rch_lessons.php?sort_by=audi LECTURE - PPT SLIDE EARLY EARTH ANIMATION LS-HHMI Time line Activity modifed from Glencoe Access Excellence Evolution: Teaching Radioactive Decay: Radioactive Half-Life and Dating Techniques Daniel Gray html html Determining age of rocks and fossils

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. References Biology: The Dynamics of Life; Glencoe x.htmlhttp:// x.html C/1995/ C/1995/

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 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

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 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

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 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 - HOW HOT WOULD THE EARTH BE? 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 WHAT IS MISSING?

EVIDENCE SHOWS: Some O 2 was present on the early earth because it contained much water vapour, and photodissociation of water in the upper layers of the atmosphere produces oxygen. Another reason is that large amounts of oxidized materials exist in the Precambrian geological strata. Yet another reason to conclude free oxygen existed on the early earth is that it is widely believed that photosynthetic organisms existed very soon after the earth had formed

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 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

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. WHAT EVIDENCE DO SCIENTISTS USE? FOSSILS! –TRACE –MOLD –CAST –AMBER –IMPRINT –PETRIFIED Images courtesy of the UC Museum of Paleontology Understanding Evolution:

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. WHERE ARE FOSSILS USUALLY FOUND? WHO STUDIES THESE? HOW DO SCIENTISTS DETERMINE THE AGE OF SOMETHING BILLIONS OF YEARS OLD? –RELATIVE DATING –RADIOMETRIC DATING Understanding Evolution:

Think analytically! What assumptions are being made in geologic and radiometric dating? Understanding Evolution:

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 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

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. GEOLOGICAL TIME TOO OLD FOR YEARS OR MONTHS FOUR ERAS DEPENDING ON WHICH ORGANISMS LIVED PRECAMBRIAN PALEOZOIC MESOZOIC CENOZOIC

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. WHY DO WE HAVE DIFFERENT ERA’S? Image courtesy of the UC Museum of Paleontology Understanding Evolution:

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. PRECAMBRIAN WHAT DO SCIENTISTS THINK WAS ALIVE WAY BACK THEN?? BACTERIA THIS ERA LASTED FOR BILLIONS OF YEARS UNTIL MORE LIVING ORGANISMS EVOLVED Dr Gordon Beakes © University of Newcastle upon Tyne licensed Dr Tom Tregenza © Tom Tregenza IMAGES for use through the Centre for Bioscience ImageBank,

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. PALEOZOIC ERA 540 MILLION YEARS AGO!! NOW THE EARTH IS GETTING LARGER LIFE! FIRST PART OF PALEOZOIC IS CALLED CAMBRIAN PROTISTS! SEA PLANTS! SEA ANIMALS! LAND PLANTS! LAND ANIMALS! WHAT ENDED THE PALEOZOIC ERA?? MASS EXTINCTION! Dr. Thomas W. Kammer IMAGES for use through the Centre for Bioscience ImageBank,

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Image courtesy of the UC Museum of Paleontology Understanding Evolution:

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. MESOZOIC ERA 245 MILLION YEARS AGO!! DINOSAURS REPTILES SMALL MAMMALS APPEAR BIRDS EVOLVE PLATE TECTONICS WHAT ENDED THE MESOZOIC ERA? MASS EXTINCTION! ? METERORITE

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Image courtesy of the UC Museum of Paleontology Understanding Evolution:

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. CENOZOIC ERA 66 MILLION YEARS AGO! MAMMALS FLOURISH PRIMATES ABOUT 30 MILLION YEARS AGO MODERN HUMAN SPECIES – ABOUT 200,000 YEARS AGO

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Tom Tregenza © Tom Tregenza Dr Gordon Beakes © University of Newcastle upon Tyne Prof Paul F. Brain © University of Wales, Swansea licensed for use through the Centre for Bioscience ImageBank,

EVIDENCE SHOWS… Fossils of the same kind of organism are found in different strata, “millions of years” apart Think about what would cause layering of fossils (liquid environment, different densities) Oxidation is evident in “early” rock strata

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 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

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. HOW WERE THE FIRST CELLS MADE? DOES ANYONE KNOW FOR SURE? SPONATEOUS GENERATION VS BIOGENESIS FRANCESCO REDI LOUIS PASTEUR’S EXPERIMENT

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. LOUIS PASTEUR 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. This prevented microorganisms in the air from entering the flask, yet allowed air to flow freely. If the swan neck was broken, microbes could enter the flask and grow.

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. ALEXANDER OPARIN - CREATION OF MACROMOLECULES WITHOUT OXYGEN STANLEY MILLER AND HAROLD UREY EXPERIMENT creative commons copyright

Problems with Miller/Urey experiment - Probably oxygen-rich with nitrogen, or CO2 - Volcanoes a major source of gases - High concentration of organic matter needed to produce more complex molecules (100X sewer water) - Proteins not stable (high UV light, changing acid/base conditions, changing temperature, reactions between side chains) - less than half of the 20 amino acids formed. No complexity. No dipeptides.

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. FIRST BACTERIA AROUND 3.5 BILLION YEARS AGO 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 ONE CELL ORGANISMS NOW! Dr Gordon Beakes © University of Newcastle upon Tyne licensed for use through the Centre for Bioscience ImageBank,

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. No explanation of the ORIGIN of life. Dr Gordon Beakes © University of Newcastle upon Tyne licensed for use through the Centre for Bioscience ImageBank,

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. 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

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. evolution.berkeley.edu/evolibrary/article/0_0_0/endosymbiosis_03 ENDOSYMBIOSIS BEGINNING OF THE EUKARYOTIC CELLS EVIDENCE FOR ENDOSYMBIOSIS DNA

PROBLEMS with ENDOSYMBIOSIS No microtubules in prokaryotes –Mitosis –Motility –Movement within the cell “vast majority of genes controlling mitochondria and chloroplasts are actually located in the central nucleus rather than in the organelles themselves” Dr. Christian de Duve Why would the cell not digest this foreign body? How/why would a free-living cell lose organelles and become dependent on its “host”?