Clues about Evolution - Fossils - PowerPoint PPT Presentation

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Clues about Evolution - Fossils

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  1. Clues about Evolution - Fossils

  2. 1. Define the 5 types of fossils • Mineralized Fossils – minerals can replace wood or bone to create a piece of petrified wood or mineralized bone fossil. • Imprint Fossil – a leaf, feather, bone or entire body of an organism can leave an imprint on sediment that will harden into a rock.

  3. Frozen Fossil – the remains of organisms can be trapped in ice that remains frozen for 1000’s of years • Cast Fossil – minerals can fill in the hollows of animal tracks or other parts of an organism to create a cast.

  4. Amber Fossil – when the sticky resin of certain cone-bearing plants hardens over time, amber forms. It can contain the remains of organism.

  5. 2. What is a fossil? • The remains, an imprint, or a trace of a prehistoric organism.

  6. 3. What type of rock will you find most fossils located in? What are 3 examples of this type of rock? • Sedimentary • Limestone • Sandstone • Shale

  7. What type of sedimentary rock will you find the most fossils? • Limestone

  8. What does the fossil record give us? • Information about organisms that lived in the past.

  9. What are the two basic methods of determining a fossil’s age? • Relative Dating • Radiometric Dating

  10. Explain relative dating. • Uses the ages of the layers of sedimentary rocks • Ex – a fossil found between 30,000 year old and 50,000 year old rocks make a fossil to be between 30,000-50,000 years old.

  11. Explain radiometric dating. • Uses radioactive elements (gives off radiation) • The amount of radioactive element compared to the amount of nonradioactive element in the rock that the fossil is found in will tell how old the fossil is.

  12. Where will you find younger layers of rocks? • Closer to the top of the ground

  13. Where will you find older layers of rocks? • Farther underground

  14. Does relative dating produce an approximate or estimate age of the fossil? • Estimate

  15. Which method is more accurate – relative dating or radiometric dating? • Radiometric Dating

  16. Why are there gaps in the fossil record? • Most organisms do not become fossils.

  17. What provides indirect evidence that evolution has occurred? • Fossils

  18. What is embryology? • The study of embryos and their development. • look on page. 167 • Fish/Chicken/Rabbit embryos

  19. Explain what homologous structures are? Give 4 examples. • Structures made up of the same kind of bones. • Homologous – body parts that are similar in origin and structure • Porpoise flipper • Frog forelimb • Human arm • Bat wing

  20. What are vestigial structures? • Structures that don’t seem to have a function. • Ex: snakes no longer have back legs, but have a pelvic bone

  21. How does DNA help with the theory of evolution? • DNA can be compared from living organisms to identify similarities among species. • Ancient DNA shows evidence of how species evolved from their extinct ancestors. • Determine how closely related organisms are. • Dogs and Bears