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Revision of the current theories of origin and evolution of life

Revision of the current theories of origin and evolution of life

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3ero 1 historyof life mine 3ero 1 historyof life mine Presentation Transcript

  • History of Life • How did all begin??
  • What are the theories that explain life? Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
  • 3 D . 1 . 1
  • Big Bang • 13,600 years ago • Galaxies are moving away from us • Black hole areas of intense gravitational pressure particles collide rise in temperature quarks Protons neutron s electron s atoms H He (hellium) Temperature fell Matter concentrated
  • 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? No O2 Too reactive 1st organic molecules didn‟t oxidize
  • • The energy for forming the organic molecules was provided by: – frequent thunder storms and lightning strikes – volcanic activity – meteorite bombardment – high temperatures due to greenhouse gases – UV radiation (no ozone so was extreme) The organic molecules may have been generated on Earth or introduced from space.
  • HOW WERE THE FIRST CELLS MADE? • DOES ANYONE KNOW FOR SURE? • SPONATEOUS GENERATION VS BIOGENESIS Tales of Miletus/Aristotle 4 elements • FRANCESCO REDI • LOUIS PASTEUR‟S EXPERIMENT
  • 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
  • Biogenesi s Earth‟s atmosphere was „reducing‟ in the early days. It did not contain oxygen gas until after plants started photosynthesising The atmosphere contained: Hydrogen Nitrogen Water vapour Methane Ammonia Hydrogen sulfide The gases came from abundant volcanic activity
  • Primitive atmosphere + radiation ORGANIC MOLECULES C+H+O= CARBOHYDRATES C+H+O= LIPIDS C+H+O+N+S= AA
  • • ALEXANDER OPARIN - CREATION OF MACROMOLECULES WITHOUT OXYGEN (BIOGENESIS) • STANLEY MILLER AND HAROLD UREY EXPERIMENT COACERVATES With RIBONUCLEIC ACIDS (multiplication) ORGANIC MOLECULES RAIN  OCEANS LIPIDS +PROTEINS = MEMBRANE
  • • FIRST BACTERIA AROUND 3.5 BILLION YEARS AGO • SOME ARE CYANOBACTERIA - THESE ARE PHOTOSYNTHETIC BACTERIA • 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? ONE CELL ORGANISMS NOW! Their own food+ O2 PROCARIOTS UNICELLULAR
  • ENDOSYMBIOSIS BEGINNING OF THE EUKARYOTIC CELLS • EVIDENCE FOR ENDOSYMBIOSIS • DNA
  • Mammals Flatworms Annelids Insects Coelenterates Fish Birds Reptiles Crustacea Amphibia Single celled organisms Monocots Herbs Shrubs Trees Dicots Flowering plants Conifers Mosses Liverworts Algae Ferns Fungi Multicellular plants Multicellular animals Mollusc
  • Life introduced from outer space!!! Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. • Panspermia- “seeds everywhere” – Life came from space on comets • Hydrocarbons, amino acids, water(s) and bacteria
  • Fixism is is the theory that says that life on earth has always been composed by the species we have today. Creationism is a religious form of fixism. Fixism vs Evolutionism Binomial nomenclature/ father of modern taxonomy the rules of heredity/ genes
  • Lamarck‟s Theory Fixism vs Evolutionism • First Evolutionist • Acquired traits can be inherited NO!!! • Use and Disuse • Adaptation – Organisms change as their environment changes
  • Darwin‟s Theory • Published “Origin of Species” • Traveled around the world in the Beagle • He proposed that: – Organisms produce more offsprings than the available resources can support – Organisms fight for limited resources like food, territory, and other necessities of life. Only those who survive can produce their own offspring – Variation exists within species. – Natural Selection - The environment selects organisms with beneficial traits
  • EVOLUTION NATURAL SELECTION ADAPTATION
  • Gradual change from one form to another through a period of time The environment selects organisms with beneficial traits A form modified to fit a changed environment
  • Evidence of Evolution • Any preserved part or tissue of an organism that once lived. FOSSIL
  • Types of Fossils Casts The mold is filled with another material Molds Hard body structures Imprints Feathers and leaves that form impressions on rocks Petrified Fossils When minerals replace the hard parts of organisms
  • Biochemical Evidences • Indicate that some organisms have similar DNA sequences, which suggest common ancestry DNA
  • VARIATION Patterns of Evolution Divergent Related organisms become very different Convergent Distantly related organisms develop similar characteristics ADAPTIVE RADIATION CONVERGENT EVOLUTION
  • OTHER EVIDENCE OF EVOLUTION – EMBRYOS – VESTIGIAL STRUCTURE APPENDIX- COCCYX-PLICA SEMILUNARIS(eye)- MUSCLES OF THE EAR- GOOSE BUMPS-PALMAR GRASP REFLEX
  • WHAT IS SPECIATION? • GEOGRAPHIC ISOLATION • REPRODUCTIVE ISOLATION
  • Who can say we are not relatives??