Transcript Slide 1
Stromatolites: layers of rock with fossils Origin of Life • Big Bang Theory: formation of the universe (20 billion years ago=bya) • Earth formed 4.5 bya • First atmosphere: Core hydrogen, water vapor, nitrogen, methane, ammonia • What is missing?? FREE OXYGEN Crust Miller Experiment Inorganic Molecules Organic Molecules Electricity (carbohydrates=sugars, Lipids=fats, proteins, DNA) (hydrogen, water vapor,nitrogen, ammonia) No electricity 3.5 bya, so what could cause a spark? First life on earth 3.5 bya, prokaryotic cells Prokaryotic cells Eukaryotic cells (1.5 bya) Miller Experiment: the origin of life Plate Tectonics Plate Tectonics • What is it called, when plates move against each other? • An earthquake! • What is it called where the plates meet? • Earthquake fault • What earthquake fault do we live near? • San Andreas Fault • Earthquake Kit?? Continental Drift Continental Drift Pangaea: continents in one land mass Laurasia: Gondwana: N. America Europe Asia Africa, S. America Australia, Antarctica, India Cenozoic Mesozoic Paleozoic •Quaternary: modern man •Tertiary: radiation of mammals __________________________________ •Cretaceous: mass extinction of dinosaurs •Jurassic: dinosaurs dominant •Triassic: first dinosaurs __________________________________ •Permian: mass extinction of marine life •Carboniferous: first reptiles •Devonian: first amphibians •Ordovician: first fishes •Cambrian: marine life abundant •Precambrian: first life on earth Past vs. Current Extinction Past Current •Slow •Natural Causes •Extinction with replacement •Fast •Human Causes •Extinction without replacement Taxonomy • Linnaeus/binomial name (Genus species) • Humans = Homo sapiens • Kingdom, Phylum, Class, Order, Family, Genus, Species • Homology = similarity in structure due to a common ancestor • Analogy = similarity in function not due to a common ancestor • DNA comparison Homologous Structures Schools of Taxonomy • Phenetics: looks for similarity and differences whether homology or analogy • Phylogenetics: use homologies to map evolutionary relationship • Cladistics Clade = evolutionary branch Cladogram = series of dichotomous forks