FOSSILS LESSON 1 - PowerPoint PPT Presentation

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  2. What are Fossils?Fossils form when living things die and are buried by sediment. The sediment hardens into rock and preserves the shapes of the organism What happens next? The sediment becomes rock preserving the remains.

  3. What are the kinds of fossils?1.Molds - A hollow area in sediment in the shape of an organism or part of an organism. A mold forms when the organism is buried in sediment.

  4. Cast A solid copy of the shape of an organism. Molds and casts can preserve fine details. external mold of the shell of Eumorphocerasgirtyi Elias 1956

  5. Petrified fossils Fossils in which minerals replace all of an organism, or a part such as a dinosaur bone. This can also happen to wood such as tree trunks.

  6. Carbon film An extremely thin coating of carbon on rock. When sediment buries an organism, some gases escape from the sediment, leaving carbon behind.

  7. Trace fossils Provides evidence of the activities of ancient organisms. A fossilized footprint is one example. A print is buried by sediment, which slowly becomes solid rock. Below is a trilobite trace fossil.

  8. Preserved Remains Organisms trapped in sticky tar or tree resin. When the resin hardens, it becomes a substance called amber. Freezing can also preserve remains.

  9. Bog body Tollund Man lived in the 4th century BCE. Bog bodies, which are also known as bog people, are the naturally preserved human corpses found in the sphagnum bogs in Northern Europe. Unlike most ancient human remains, bog bodies have retained their skin and internal organs due to the unusual conditions of the surrounding area. These conditions include highly acidicwater, low temperature, and a lack of oxygen, combining to preserve but severely tan their skin. Despite the fact that their skin is preserved, their bones are generally not, as the acid in the peat dissolves the calcium phosphate of bone.



  12. What Do Fossils Show? The fossil record provides evidence about the history of life and past environments on Earth. The fossil record also shows how different groups of organisms have changed over time.

  13. PaleontologistsScientist who study fossils! PALEONTOLOGIST 10:00 So.. You want to be a paleontologist

  14. Fossils and past environments DINOSAURS AND FOSSILS (5:37)

  15. Change and the fossil record Evolution The change in living things over time. Extinct A type of organism that no longer exists and will never live on earth.

  16. As organisms adapt to a specific environment and life style, traits once useful can become irrelevant and may be lost. A classic example is the reduction of hind limbs during the evolution of whales.  Evolution of the Horse Their beaks have evolved over time to be best suited to their function. For example, the finches who eat grubs have a thin extended beak to poke into holes in the ground and extract the grubs. Finches who eat buds and fruit would be less successful at doing this, while their claw like beaks can grind down their food and thus give them a selective advantage in circumstances where buds are the only real food source for finches.

  17. extinct EARTH’S CHANGINH ENVIRONMENT (9:05) Desmostylushesperus, an amphibious mammal from the Miocene that lived in North America and Eastern Asia

  18. REVIEW AND REINFORCE 7. Describe how a mold is related to a cast.   8. What can a paleontologist tell from fossil footprints of a dinosaur?   9. What does the fossil record reveal about the evolution of life on Earth?

  19. ANSWER KEY 7. A mold is an empty space in rock in the shape of an organism or part of an organism. If water carrying dissolved minerals and sediment seeps and deposits those minerals and sediments into the mold, the result is a cast in the shape of the organism.   8.Fossil footprints can provide clues about the dinosaur’s size and behavior.   9. The fossil record provides evidence that many different organisms have existed at different times. The fossil record also shows that groups of organisms have changed over time.