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Organization of Life on earth

Its Origin and Evolution. Organization of Life on earth. Levels of Organization. Biosphere Ecosystems Communities Populations Organisms Organs and Organ Systems Tissues Cells Organelles Molecules. Levels of Organization. Biosphere.

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Organization of Life on earth

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  1. Its Origin and Evolution Organization of Life on earth

  2. Levels of Organization • Biosphere • Ecosystems • Communities • Populations • Organisms • Organs and Organ Systems • Tissues • Cells • Organelles • Molecules

  3. Levels of Organization

  4. Biosphere • Everywhere within the Earth’s atmosphere where life exists.

  5. Ecosystems • The biotic and abiotic factors within an environment • Interactions between organisms • Interactions between organisms and the environment • Cycling of Nutrients • Energy flow

  6. Community • All living organisms in a particular region

  7. Population • All individuals of a species in a particular area

  8. Organism • A single living thing

  9. Organs & Organ Systems • Organ • Specialized body parts made of tissues • Tissues work together to perform a specific function • Organ System • Groups of organs that work together to perform specific functions

  10. Tissue • A group of similar cells

  11. Cell • Basic unit of: • Life • Structure and function • Contains DNA

  12. Organelle • Structural component of a cell

  13. Molecule • Chemical structure consisting of atoms

  14. Diversity of Life • Domain Bacteria • Prokaryotic • Domain Archaea • Prokaryotic • Live under extreme conditions • Domain Eukarya • Protists (unicellular eukaryotes) • Kingdom Plantae (photosynthetic) • Kingdom Fungi (decomposers) • Kingdom Animalia (ingest others)

  15. Evolution • On the Origin of Species, Charles Darwin • Contemporary species arose from a succession of ancestors • “descent with modification” • Natural Selection • Mechanism for descent with modification

  16. Early Earth & the Origin of Life • Chemical and physical processes on early Earth may have produced very simple cells through a sequence of stages: 1. Abiotic synthesis of small organic molecules 2. Joining of these small molecules into polymers 3. Packaging of molecules into “protobionts” 4. Origin of self-replicating molecules

  17. Earth formed about 4.6 billion years ago • Earth’s early atmosphere contained water vapor and chemicals released by volcanic eruptions • Experiments simulating an early Earth atmosphere produced organic molecules from inorganic precursors, but such an atmosphere on early Earth is unlikely

  18. Miller & Urey CH4 Water vapor Electrode NH3 H2 Condenser Cold water Cooled water containing organic molecules H2O Sample for chemical analysis

  19. Other Explanations • synthesis near submerged volcanoes and deep-sea vents

  20. Other Explanations • Extraterrestrial Sources • Carbon compounds have been found in some meteorites that landed on Earth

  21. Abiotic Synthesis of Polymers • Small organic molecules polymerize when they are concentrated on hot sand, clay, or rock • Protobionts • aggregates of abiotically produced molecules surrounded by a membrane or membrane-like structure • could have formed spontaneously from abiotically produced organic compounds • Example: small membrane-bounded droplets called liposomes can form when lipids or other organic molecules are added to water

  22. The first genetic material was probably RNA, not DNA • RNA molecules called ribozymes have been found to catalyze many different reactions, including: • Self-splicing • Making complementary copies of short stretches of their own sequence or other short pieces of RNA • Early protobionts with self-replicating, catalytic RNA would have been more effective at using resources and would have increased in number through natural selection

  23. Fossils • Formation • Sedimentary rocks • Low humidity • Ice • Amber • Dating • Strata & Index Fossils • Relative Dating • Radiometric Dating • Absolute Dating • Paleomagnetism

  24. Accumulating “daughter” isotope LE 26-7 1 Ratio of parent isotope to daughter isotope 2 1 Remaining “parent” isotope 4 1 8 1 16 1 2 3 4 Time (half-lives)

  25. Fossils

  26. Animation: The Geologic Record

  27. Ceno- zoic Meso- zoic Humans Paleozoic Land plants Animals Origin of solar system and Earth 1 4 Proterozoic Eon Archaean Eon Billions of years ago 2 3 Multicellular eukaryotes Prokaryotes Single-celled eukaryotes Atmospheric oxygen

  28. Geologic Time Scale • Each era is a distinct age in the history of Earth and its life, with boundaries marked by mass extinctions seen in the fossil record • Occasions when global environmental changes were so rapid and disruptive that a majority of species were swept away • Lesser extinctions mark boundaries of many periods within each era

  29. Millions of years ago 600 500 400 300 200 100 0 100 2,500 Number of taxonomic families 80 2,000 Permian mass extinction ) Extinction rate 60 1,500 Number of families ( Extinction rate ( 40 1,000 Cretaceous mass extinction LE 26-8 ) 20 500 0 0 Cambrian Ordovician Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous Paleogene Neogene Proterozoic eon Ceno- zoic Paleozoic Mesozoic

  30. Mass Extinctions • Permian • Killed about 96% of marine animal species and 8 out of 27 orders of insects • Cause = volcanic eruptions • Cretaceous • Killed many marine and terrestrial organisms, notably the dinosaurs • Cause = meteor impact • Mass extinctions = opportunities for adaptive radiations

  31. Early Life • Oldest known fossils are stromatolites • rocklike structures composed of many layers of bacteria and sediment • Date back 3.5 billion years • Prokaryotes were Earth’s sole inhabitants from 3.5 to about 2 billion years ago

  32. Electron Transport Systems • Produce ATP (adenosine triphosphate) from ADP (adenosine diphosphate)

  33. Photosynthesis • Oxygenic photosynthesis probably evolved about 3.5 billion years ago in cyanobacteria • Effects of oxygen accumulation in the atmosphere about 2.7 billion years ago: • Posed a challenge for life • Provided opportunity to gain energy from light • Allowed organisms to exploit new ecosystems

  34. Eukaryotic Life • Oldest fossils of eukaryotic cells date back 2.1 billion years • theory of endosymbiosis

  35. Cytoplasm DNA Plasma membrane Ancestral prokaryote Infolding of plasma membrane Endoplasmic reticulum Nucleus Nuclear envelope Engulfing of aerobic heterotrophic prokaryote Cell with nucleus and endomembrane system LE 26-13 Mitochondrion Mitochondrion Engulfing of photosynthetic prokaryote in some cells Ancestral heterotrophic eukaryote Plastid Ancestral photosynthetic eukaryote

  36. Evidence for Endosymbiosis • Similarities in inner membrane structures and functions • Both have their own circular DNA

  37. Multicellular Eukaryotes • The common ancestor of multicellular eukaryotes dates back 1.5 billion years • Larger organisms do not appear in the fossil record until several hundred million years later

  38. Multicellular Eukaryotes • Colonies • collections of autonomously replicating cells • Some cells became specialized for different functions

  39. The “Cambrian Explosion” • Most of the major phyla of animals • Cnidaria and Porifera date back to the late Proterozoic • Molecular evidence suggests that many animal phyla originated and began to diverge between 1 billion and 700 million years ago

  40. 500 Sponges Cnidarians Echinoderms Chordates Brachiopods Annelids Molluscs Arthropods Early Paleozoic era (Cambrian period) Millions of years ago LE 26-17 542 Late Proterozoic eon

  41. The Move to Land • Plants, fungi, and animals colonized land about 500 million years ago • Symbiotic relationships

  42. Eurasian Plate North American Plate Philippine Plate Caribbean Plate Juan de Fuca Plate Arabian Plate Indian Plate Cocos Plate Continental Drift South American Plate Pacific Plate Nazca Plate African Plate Australian Plate Antarctic Plate Scotia Plate

  43. Volcanoes and volcanic islands Trench Oceanic ridge LE 26-19 Subduction zone Oceanic crust Seafloor spreading

  44. By about 10 million years ago, Earth’s youngest major mountain range, the Himalayas, formed as a result of India’s collision with Eurasia during the Cenozoic. The continents continue to drift today. 0 Cenozoic Eurasia North America By the end of the Mesozoic, Laurasia and Gondwana separated into the present-day continents. 65.5 Africa South America India Madagascar Australia Antarctica By the mid-Mesozoic Pangaea split into northern (Laurasia) and southern (Gondwana) landmasses. Laurasia LE 26-20 135 Gondwana Mesozoic Millions of years ago At the end of the Paleozoic, all of Earth’s landmasses were joined in the supercontinent Pangaea. 251 Pangaea Paleozoic

  45. Tree of Life • The five kingdom system has been replaced by three domains: Archaea, Bacteria, and Eukarya • Each domain has been split into kingdoms • Kingdom • Phylum • Class • Order • Family • Genus • Species

  46. Chapter 27 Chapter 28 Red algae Charophyceans Chlorophytes Proteobacteria Chlamydias Spirochetes Cyanobacteria Korarchaeotes Gram-positive bacteria Cercozoans, radiolarians Diplomonads, parabasalids Euglenozoans Euryarchaeotes, crenarchaeotes, nanoarchaeotes Alveolates (dinoflagellates, apicomplexans, ciliates) Stramenopiles (water molds, diatoms, golden algae, brown algae) LE 26-22a Domain Eukarya Domain Archaea Domain Bacteria Universal ancestor

  47. Chapter 29 Chapter 30 Chapter 28 Chapter 31 Chapter 32 Chapters 33, 34 Chytrids Sponges Sac fungi Club fungi Zygote fungi Angiosperms Choanoflagellates Cnidarians (jellies, coral) Arbuscular mycorrhizal fungi Seedless vascular plants (ferns) Gymnosperms Amoebozoans (amoebas, slime molds) Bryophytes (mosses, liverworts, hornworts) Bilaterally symmetrical animals (annelids, arthropods, molluscs, echinoderms, vertebrates) Plants Animals LE 26-22b Fungi

  48. Theories of Evolution • Gradualism • Hutton & Lyell • Lamarck • Use and Disuse • Darwin • On the Origin of Species • Descent with Modification • Common Ancestors • Natural Selection

  49. Natural Selection • How do environmental changes affect a population?

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