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Tree of Evolution

Tree of Evolution. Conditions of Early Earth (greater radiation and igneous activity) lead to the synthesis of abiotic (non-living) molecules nucleic acids (RNA) & amino acids led to the formation of protobionts (droplets with membranes that maintained the internal environment)

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Tree of Evolution

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  1. Tree of Evolution • Conditions of Early Earth (greater radiation and igneous activity) lead to the synthesis of abiotic (non-living) molecules • nucleic acids (RNA) & amino acids • led to the formation of protobionts (droplets with membranes that maintained the internal environment) • origin of self replication to produce new organisms • Sources for the carbonaceous molecules could have come from meteorites or from the substrate. Environment in early Earth (~3.6 billion years ago) was a reducing environment (electron adding) creating the opportunity for the formation of new molecules from methane and ammonia.

  2. Fossil record • Prokaryotes • Stromatolites - beds of sediment containing the byproducts of bacterial metabolism (shows blooms followed by extinctions) • oldest ~3.5 billion years - anaerobes • halophiles • methanogens

  3. Fossil Record • photosynthesis and the oxygen revolution (cyanobacteria) • prokaryotes start using oxygen as a source of reducing energy to form new molecules • photoautotrophs

  4. Fossil Record • Eukaryotes (~2.1 billion years ago) • arose from the symbiotic relationship and transfer of genetic material between prokaryotes • organisms resemble simple single celled algae • Endosymbionts - mitochondria & plastids • endosymbionts take over the role of energy making paving the path for multicellular organisms • genetic annealing (combining of genomes) and colony formation leads to specialization and the multicellular organism • multicellular organisms (~1.5 billion years ago) • most confined to areas of water and heat (snowball Earth hypothesis) resembling small algae • Cambrian explosion (explosion of life ~ 700mil years ago)

  5. Geologic time scale • eon - longest division • Archeon - 1st eon of Earth ~3.9 to 2.5 billion years ago • Proterozoic - lasted for the next 2 billion years • Phanerozoic - most resent with evidence of life • era - there are three eras per eon • Paleozoic - ~543 million years ago "Age of Invertebrates" • fossils of both land and plants • Mesozoic - ~248 million years ago "Age of Reptiles" • dinosaurs • Cenozoic - ~most recent "Age of Mammals" • appearance of humans

  6. Geologic time scale • periods • Precambrian - all periods before the paleozoic era • rocks lack index fossils • fossil evidence is contained in stromatolites- layers of bacteria and algae • content is high in valuable metals - Au, Ag, Cu, ... • Cambrian • invertebrates • trilobites is the most common index fossil ~500 million years ago

  7. Geologic time scale • Ordovician • invertebrates • graptolites are the most common index fossil - lived in colonies • Silurian - appearance of terrestrial animals • Devonian - Age of the Fishes - 1st fossils of lungfish found • Carboniferous - appearance of reptiles and vertebrates

  8. Geologic time scale • Permian - formation of Pangaea - nearly 1/2 of known fossils extinct by the end of the period • marks the end of the Paleozoic era • Triassic - Jurassic - Cretacious are periods of the Mesozoic • rise and fall of the dinosaurs • Paleogene, Neogene, & Quarternary are periods of the Cenozoic • formation of modern climate features and the rise of man

  9. Geologic time scale • Epochs (part of the Cenozoic) • Holocene… Historical time begins (.01mil yrs) • Pleistocene… Ice Ages… Humans appear (1.8mil yrs) • Pliocene… Origin of genus Homo (5.3mil yrs) • Miocene… Continued radiation of species (23mil yrs) • Apelike ancestors of humans • Oligocene… Origin of primate groups (33.9mil yrs) • Eocene… Angiosperms dominate (55.8mil yrs) • Paleocene… massive radiation of mammals, birds, & insects (65.5mil yrs)

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