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EVOLUTION CONTINUED “Where’s the Evidence?!”

EVOLUTION CONTINUED “Where’s the Evidence?!”. Chap. 13 The Macroevolutionary Puzzle. Vocabulary Read (282-292) (740)(327) . 109 paleontologist vestigial structure homologous structure gradualism punctuated equilibrium continental drift analogous character isotope

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EVOLUTION CONTINUED “Where’s the Evidence?!”

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  1. EVOLUTION CONTINUED“Where’s the Evidence?!” Chap. 13 The Macroevolutionary Puzzle

  2. VocabularyRead (282-292)(740)(327) • 109 paleontologist • vestigial structure • homologous structure • gradualism • punctuated equilibrium • continental drift • analogous character • isotope • 117 radioisotope

  3. Radiometric Dating or Radioactive Dating • Isotope- 1 form that an element can have. Number of neutrons is variable between isotopes of the same element. (number of electrons and protons stays the same) • Minerals possess radioactive isotopes (give off energy and subatomic particles) that decay (breakdown) into smaller isotopes.

  4. Formed in igneous rock, the minerals grow as the liquid rock cools. • Amounts of the “parent” (or original) and “daughter” isotopes can be measured in a sample collected today. • The rate of decay can be calculated experimentally. • “Half Life” is a common unit of measure of the rate of break down.

  5. Radioactive parent nucleus Decay process Daughter nucleus p p p p p p p Atomic mass decreases by 4; atomic number decreases by 2 p p p p p p p Proton Neutron p Alpha particle Emission of 2 protons and 2 neutrons (alpha particle) (a) Alpha decay p p p p p p Atomic mass not changed much; atomic number increases by 1 because Neutron becomes proton p p p p p p p p p p p p p Beta particle An electron (beta particle) is ejected from the nucleus (b) Beta decay p p p Atomic mass not changed much; atomic number decreases by 1 p p p p p p p p p p p p p p p p p electron combines with a proton to form a neutron Beta particle (c) Electron capture

  6. Sample Problems • The half-life of Potassium 40 is 1.3 million years. It breaks down into Argon 40 • 1) If an original rock sample contains 200 micrograms of Potassium 40, how much would remain after two half-lives?

  7. Uranium 238 has a half-life of 4.51 billion years and decays into Lead 206 • 2) A newly discovered rock sample has 15 micrograms of Uranium 238 and 105 micrograms of the daughter material Lead 206. How old is this rock?

  8. Homework 2 sides in binder • The next 2 slides are more practice problems to work on later.

  9. U238 decays into Pb206 in 4.51 billion years (HALF LIFE) • How much U238 and Pb206 are present in a sample after 2 HALF LIVES? • (original sample is 300 grams) • U238 75 grams Pb206 225 grams • How long would 2 half lives be? • 9.02 billion years

  10. How old is an igneous rock sample containing 275g U238 and 1925g Pb206? • 3 x 4.51 = 13.53 billion years

  11. V. EVIDENCE OF EVOLUTION FROM FOSSILS “any evidence of once living creatures” Where are fossils most likely to be found?

  12. A. 4 Types of Fossils • 1. Compression- organic material between layers of sediment, Some details can be observed . ex. fern frond, fish • 2. Impression- external shape and form, no organic matter ex. foot print, limb print • 3. Mold and cast- external features in one layer, then the item itself is replaced by other sediments ex. Egg, shark tooth • 4. Petrifaction- tissues are gradually infiltrated by minerals. No organic material remains ex. petrified wood

  13. How impression fossils form (the most common type) 8_10 Shells settle on ocean floor Cast forms when mold is filled in with mineral water Rock broken to reveal fossil cast Rock broken to reveal external mold of shell Shells buried in sediment Mold, or cavity, forms when original shell material is dissolved

  14. BOG people • Bogs filled with danger where you could easily get lost and drown. It's not hard to understand why tribes of long ago used to believe that gods and ghosts inhabited the swamps. Gifts and sacrifices were thought to win their good graces. Prehistoric man offered all kinds of objects to the bogs. So it was that bogs became gigantic offering locations.

  15. Never before had there been so many bog bodies and offering all in one place. Schatten uit het veen provides an impressive picture of the beliefs and rituals of our ancestors in North-western Europe.

  16. B. Distribution of fossils in layers of rocks? YOUNGEST many varieties and great complexity first fossils were aquatic and some are extinct few varieties and little complexity Fossils in every layer OLDEST STRATIFICATION

  17. Each geologic time period is characterized by certain fossils (remember the GEO TIME TABLE?)

  18. Why do organisms disappear from the fossil record? • 1. unable to adapt to a changing environment • Ex. lake drying, cooling climate ,glaciers • 2. out competed by organisms more suitable to the new environment • Ex. reptiles competing with early mammals • Or fish vs. amminoids

  19. Diagram of species abundance over time • Flowering plants and ferns

  20. Diagram of species abundance over time • Bony fish and amminoids

  21. Notes in student binder • GREAT! Less writing

  22. VI CONTINENTAL DRIFT or PLATE TECTONICS • Alfred Wegener early 20th century • initially incorrect explanation but modified theory is widely accepted (seafloor stationary and continents move WRONG!!!!)

  23. 10 MAJOR PLATES AND MANY MINOR PLATES UP TO 100 KM THICK • Continents ride on the moving crustal plates (less dense material )

  24. These are the possible events at the boundary of plates • Slide • Spread

  25. These are the possible events at the boundary of plates • Subduction • Subduction w/continents

  26. 1. Theory and Evidence • OLD • 1. puzzle pieces • 2. fossil distribution • 3. sediment layers "Gandwanan Sequence" similar geology on the 4 southern continents sandstone with coal • black shale • glacial till

  27. NEW • 1. earthquake distribution • shallow quakes at ridges Mid Atlantic • shallow and deep quakes at trenches subduction • distribution of the RING OF FIRE pg 303 2. Movement of plates can be measured from space 3. Dating rocks on opposite sides of ridges Draw ring of fire on map

  28. End of geological evidence • * the earth is old and has changed (volcanoes, glaciers, earthquakes) • * organisms that lived in the past are now gone • * different organism appear in later rocks than in early ones • therefore new organisms must be developing from old EVOLUTION

  29. VII EVIDENCE OF EVOLUTION FROM LIVING CREATURES • Common Ancestry through comparative anatomy • Georges Buffon 1760 French Naturalist • - observed the feet and legs of many animals • - concluded that they were but variations on a single theme

  30. "The ancestors of backboned animals must have had the same limb structure but has been modified for the life of the individual" • *This suggests that organisms have changed with time and had a distant common ancestor **

  31. What similarities must exist for organisms to have a common ancestor? • 1. anatomy (talons, bones, coloration) • 2. physiology (DNA, hemoglobin, digestion) • 3. behavior ( instinct, learning)

  32. Evidence of Evolution from living creatures continued • HOMOLOGOUS STRUCTURES- organs or parts that are structurally similar but may have different functions (Indicates common ancestry or origin) SEE HANDOUT

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