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Evolution

Chapters 13 and 14. Evolution. CHARLES DARWIN 1809-1882. TRIP ON THE BEAGLE 1830 ’ S BEAGLE TOURED AROUND THE WORLD SPENT TIME ON THE GALAPAGOS ISLANDS-OFF THE COAST OF ECUADOR TRIP LASTED 5 YEARS COLLECTED MANY SAMPLES, SPECIMENS AND SENT THEM HOME

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Evolution

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  1. Chapters 13 and 14 Evolution

  2. CHARLES DARWIN 1809-1882

  3. TRIP ON THE BEAGLE • 1830’S BEAGLE • TOURED AROUND THE WORLD • SPENT TIME ON THE GALAPAGOS ISLANDS-OFF THE COAST OF ECUADOR • TRIP LASTED 5 YEARS • COLLECTED MANY SAMPLES, SPECIMENS AND SENT THEM HOME • KEPT A JOURNAL OF HIS OBSERVATIONS FOR THE ENTIRE TRIP

  4. DARWIN’S OBSERVATIONS ON HIS TRIP • HE SAW MUCH DIVERISTY IN ANIMALS AND PLANTS AND FOUND FOSSILS OF THINGS NO LONGER LIVING • HE REALIZED THERE ARE AN ENORMOUS AMOUNT OF SPECIES ON EARTH • TODAY’S ESTIMATE-3-20 MILLION • BUT MORE THEN 99.9% OF ALL SPECIES THAT EVER LIVED ARE NOW EXTINCT

  5. DARWIN WONDERED: • WHERE DID ALL THESE SPECIES COME FROM AND WHY DID SOME DISAPPEAR?

  6. MORE OBSERVATIONS OF DARWIN • HE SAW MANY WAYS THAT ORGANISMS SURVIVED AND REPRODUCED • HE CALLED THIS FITNESS - PHYSICAL TRAITS & BEHAVIORS WHICH ENABLE ORGANISMS TO SURVIVE/REPRODUCE IN THEIR ENVIRONMENT

  7. DARWIN WONDERED: • HOW DID THESE ORGANISMS DEVELOP STRUCTURES THAT GAVE THEM THIS FITNESS? • WHY WERE THERE SO MANY TECHNIQUES TO SURVIVAL?

  8. DARWIN RETURNS HOME • HE BECAME VERY POPULAR DUE TO ALL THE SPECIMENS, SAMPLES HE SENT BACK • HE BECAME FRIENDS WITH CHARLES LYELL, A GEOLOGIST

  9. THE AGE OF THE EARTH • IN THE 18TH AND 19TH CENTURY SCIENTISTS HYPOTHESISED THAT THE EARTH IS VERY OLD, & CHANGED VERY SLOWLY DUE TO NATURAL FORCES-WIND, RAIN, ETC.

  10. SCIENTISTS SAW THAT THE EARTH MOVED & SHIFTED • SOME ROCK LAYERS BURY OTHERS & PUSH APART THE SEA FLOOR • THEY FOUND FOSSILS THAT RESEMBLED ORGANISMS STILL ALIVE, BUT OTHERS DID NOT • THIS INFLUENCED DARWIN’S THINKING ABOUT EVOLUTION

  11. CHARLES LYELL • STATED, “THE EARTH MUST BE VERY OLD SINCE GEOLOGICAL FORMATIONS ARE SLOW & GRADUAL” • “SCIENTISTS MUST EXPLAIN PAST EVENTS AS PROCESSES THEY CAN OBSERVE. THIS IS HOW THE SCIENTIFIC METHOD WORKS.”

  12. Charles Lyell – Principles of Geology • A book that emphasized the great age of earth and the principles of uniformitarianism

  13. Uniformitarianism – the geological structure of the earth resulted from cycles of observable processes and that these same processes operate continuously through time • Ex. Sediment deposition in rivers • These ideas influenced Darwin and he saw how the same principles could apply to organisms

  14. IN 1859, DARWIN’S “THE ORIGIN OF SPECIES” IS PUBLISHED • THIS IS 30 YRS. AFTER HIS TRIP ON THE BEAGLE – IT WAS A RADICAL IDEA FOR THE TIME • http://www.pbs.org/wgbh/evolution/darwin/index.html • DARWIN’S BOOK CONTAINED 5 KEY CONCEPTS

  15. 1.MODERN ORGANISMS ARISE THROUGH EVOLUTION

  16. 2. EACH SPECIES COMES FROM A PRECEDING ONE, THEY HAVE A COMMON ANCESTOR. COMMON DESCENT

  17. 3. FITNESS COMES FROM ADAPTATION

  18. 4. SUCCESSFUL ADAPTATION ALLOWS ORGANISMS TO SURVIVE & REPRODUCE

  19. 5. ADAPTATION IS ANY CHARACTERISTIC THAT INCREASES AN ORGANISM’S FITNESS

  20. DO NOW • 1. HOW LONG WAS DARWIN GONE ON HIS TRIP? • 2. WHAT WAS THE NAME OF HIS BOOK? • 3. HOW DID DARWIN DEFINE FITNESS?

  21. Geologic Time Scale • The geologic time scale is used by scientists to map the timing and relationships between events that have occurred during the history of the Earth. • It combines estimates of the age of geological formations as provided by radiometric dating techniques with the direct evidence of sequences and events in the rock record as assembled by geologists.

  22. GEOLOGICAL TIME SCALE

  23. GEOLOGICAL TIME-KEY EVENTS • 3.6 B.Y.A.-1ST CELLS • 580 M.Y.A.-AQUATIC PLANTS-ALGAE • 360 M.Y.A.-BONY FISH, AMPHIBIANS, INSECTS

  24. GEOLOGICAL TIME-KEY EVENTS • 245 M.Y.A.-PERMIAN EXTINCTION-MARINE ANIMALS • 144 M.Y.A. JURASSIC-AGE OF THE DINOSAURS • 65 M.Y.A.-CRETACEOUS-EXTINCTION OF DINOSOURS

  25. GEOLOGICAL TIME-KEY EVENTS • 65 M.Y.A –RADIATION (SPREADING) OF MAMMALS • 39 M.Y.A. –PRIMATES EMERGE • 7 M.Y.A.-APELIKE ANCESTORS APPEAR • 2.5 M.Y.A.-HUMANS APPEAR

  26. But how do scientists know when certain things happened or when certain organisms lived???

  27. RELATIVE DATING-NOT DATING YOUR COUSIN! • GEOLOGISTS IN THE PAST NOTICED THAT CERTAIN TYPES OF ROCK COULD ALWAYS BE FOUND IN THE SAME VERTICAL ORDER • AGE OF ROCK CAN BE ESTIMATED BY THE POSITION IN THE ROCK LAYERS • OLDER LAYERS AT THE BOTTOM, NEWER ON TOP

  28. RELATIVE DATING • Relative Dating – technique to date fossils relative to other fossils in the rocks • Law of Superposition – successive layers of rock or soil were deposited on top of one another by wind or water • lowest layers are the oldest • top layers are the youngest

  29. RADIOACTIVE DATING-YOU HAVE A GLOW ABOUT YOU!http://www.pbs.org/wgbh/evolution/library/03/3/l_033_01.html • THE AGE OF ROCK CAN BE DETERMINED BY THE ELEMENTS IT IS COMPOSED OF • MANY ELEMENTS ARE ISOTOPES-RADIOACTIVE • THE ATOMS DECAY OVER TIME-SO…

  30. RADIOACTIVE DATING CONT. • WHEN THE ATOMS DECAY THIS CHANGES THEIR CHEMICAL IDENTITY • RADIOACTIVE DECAY CAN BE MEASURED AS HALF LIFE • HALF LIFE IS THE TIME IT TAKES FOR HALF THE ATOMS TO DECAY

  31. URANIUM 238/POTASSIUM 40 • URANIUM TURNS INTO LEAD AS IT DECAYS - - HALF LIFE OF 4.5 BILLION YEARS • POTASSIUM TURNS INTO ARGON AS IT DECAYS – HALF LIFE OF 1.3 BILLION YEARS. • SCIENTISTS CAN DETERMINE ROCK AGES USING RATIOS • FOSSILS FOUND IN THE ROCK THAT ARE DATED ARE ASSUMED TO BE THE SAME AGE AS THE ROCKS

  32. C14, CARBON DATING FOR ONCE LIVING ORGANISMS • C14 CARBON – HALF LIFE OF 5770 YEARS • CARBON CAN EXIST AS RADIOACTIVE C14 OR NON RADIOACTIVE C12 • IN 5770 YEARS ½ THE C-14 TURNS INTO • N-14

  33. C14, CARBON DATING • THEY CAN THEN DETERMINE THE AGE OF THESE CELLS • THIS METHOD IS ONLY GOOD FOR ITEMS < 60,000 Y.O. • OFTEN DATE PRE-HISTORIC HUMANS USING THIS METHOD

  34. DO NOW • 1. C14 DATING IS GOOD FOR ITEMS THAT ARE > 1MILLION YEARS OLD, True OR False? • 2. WHEN URANIUM DECAYS IT BECOMES_______? • 3. WHAT IS THE DEFINITION OF HALF LIFE? • 4. MOST FOSSILS ARE MADE FROM WHAT TYPE OF ROCK?

  35. RELATIVE DATING OF FOSSILS • IF A FOSSIL IS IN A TOP LAYER-IT MUST BE? • IF A FOSSIL IS IN A BOTTOM LAYER IT MUST BE? • CAN EXACT AGE BE DETERMINED WITH THIS METHOD?

  36. The fossil record shows that change followed change on earth.

  37. Fossils • Found in the rocks • Preserved ancient remains of organisms • Some fossils looked like organisms that were alive – others did not • The fossil record shows animals that were preserved by being buried in the rocks, tar pits or tree sap • Sedimentary rock-layers of sediment cover up the animals and preserve the remains

  38. FOSSIL RECORD-INFORMATION OF PAST FORMS OF LIFE • TELLS OF MAJOR CHANGES IN THE GEOLOGICAL RECORD OF EARTH • SEA CREATURES IN ARIZONA,-COASTLINE CHANGES • GIANT FERNS IN N. AMERICA-WARMER CLIMATE • WHAT DOES A PALEONTOLOGIST STUDY?

  39. FORMATION OF FOSSILShttp://www.pbs.org/wgbh/evolution/library/04/3/l_043_01.html • MOST ARE FOUND IN SEDIMENTARY ROCK-SEDIMENT FORMS WHEN SAND & SILT FROM WATER SETTLE TO THE BOTTOM OF A BODY OF WATER • ANIMALS & PLANTS THAT DIE IN THE WATER ARE COMPRESSED INTO ROCK BY PRESSURE FROM THE WATER.

  40. FOSSIL FORMATION • http://www.classzone.com/books/earth_science/terc/content/visualizations/es2901/es2901page01.cfm?chapter_no=visualization

  41. FORMATION OF FOSSILS • BONES & TEETH MAY BE PRESERVED ON LAND BY SHIFTING SAND, MUD OR VOLCANIC ASH. • FOOTPRINTS OR SOFT TISSUE CAN BE PRESERVED IF THEY FILL WITH DUST OR ASH. THEY ARE THEN COVERED BY OTHER MATERIALS & HARDEN

  42. FORMATION OF FOSSILS • PETRIFICATION CAN OCCUR WHEN REMAINS ARE COVERED WITH WATER • DISSOLVED MINERALS FROM THE WATER REPLACE THE DECAYING TISSUES & HARDEN

  43. Petrified wood

  44. GAPS IN THE FOSSIL RECORD • WHY ARE THERE GAPS? • CONDITIONS TO FORM FOSSILS NOT PRESENT • SOME TISSUES ARE TOO SOFT TO FORM FOSSILS-JELLY FISH, WORMS • EROSION DESTROYS FOSSILS • FOSSILS CAN BE BURIED AND NOT FOUND

  45. DO NOW • 1. Which make better fossils, bone or footprints? • 2. Why are there gaps in the fossil record? • 3. Which is the cast & which one is the mold of a fossil below?

  46. COMPARISON OF LIVING ORGANISMShttp://www.pbs.org/wgbh/evolution/library/04/2/l_042_02.html • EMBRYOLOGY • CHARACTERISICS LOST IN ADULTHOOD ARE SEEN IN EMBRYOS • ALL VERTEBRATE EMBRYOS HAVE GILL POUCHES-NECK FOLDS • IN FISH DEVELOP INTO GILLS • IN HUMANS-TRACHEA • INHERITANCE FROM A FISH-LIKE ANCESTOR

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