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Chapter 17- The History of Life

Chapter 17- The History of Life. 17.1- The Fossil Record Index. What is this chapter all about?. Earth's history- Fossils provide important evidence of how life and environmental conditions have changed. Earth Science: Properties of Earth materials-

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Chapter 17- The History of Life

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  1. Chapter 17- The History of Life 17.1- The Fossil Record Index

  2. What is this chapter all about? • Earth's history- Fossils provide important evidence of how life and environmental conditions have changed. • Earth Science: Properties of Earth materials- Fossils provide evidence about the plants and animals that lived long ago and the nature of the environment at thattime.

  3. Fossil Records…? A Fossil Record: (Click A Letter) Provides Evidence of historical life on Earth, including Organisms and their evolution. Involves a complete database of fossilized specimens Shows how organisms have become extinct Is what paleontologists keep to keep record of fossils they find A B C D

  4. Correct! Fossil Records provide evidence of historical life on Earth, including organisms and how they evolved. Click To Move On to How Fossils Form

  5. Incorrect! Click To Go Back!

  6. How Fossils Form • Sedimentary Formation- • An organism lives in a certain ecosystem where sediments are prominent. (Usually a stream or river.)

  7. How Fossils Form 2. The Organism dies. At the end of an organisms life, its body starts to decay, but sometimes other options are prevalent…

  8. How Fossils Form 3. Fossils form- Most Fossils form in Sedimentary Rock. Some of this rock is formed due to rain, heat, wind etc. when rock is broken down or deposited into the into stream, rivers, or lakes. As the sediments build up over a dead organism, the organism becomes buried.

  9. How Fossils Form • 4. Quality of Preservation If Conditions are right, the remains may be kept unharmed and free from decay. The quality varies because in some cases, the small particles of rock surrounding the remains of an organism preserve and imprint its soft parts. Sometimes Volcanic Ash can help preserve the organism. This act of fossilization occurs very rarely.

  10. Who Knows…..? What is a Paleontologist?

  11. Paleontologists…. Paleontologists are Scientists who study Fossils. Roy Chapman Andrews is a famous paleontologist.

  12. Relative what…? What is Relative Dating? Scientist calculate the age of a sample based on its remaining chemical isotopes. A B Represents evolutionary time C The dating of ones relatives D To compare a fossil to another

  13. Correct! Relative Dating is when paleontologists look at a fossils age by comparing it to another fossil and its given location. Click the Picture of Relative Dating to Move On!

  14. Incorrect! Click to go Back!

  15. Radioactive Dating Radioactive Dating is the use of half-lives to determine the age of a sample. Who Knows what a half Life is? Click to see if you were right!

  16. Were They Right? AHalf Life is the length of time required for half of the radioactive atoms in a sample to decay. Cool Fact: Potassium is used to find the radioactive dating ofolderrocks while carbon is used to find the date of newer ones.

  17. Geologic Time Scale Paleontologists use the Geologic Time Scale to represent evolutionary time. Geologists Divide the time between the Precambrian Era and the present into the Paleozoic, Mesozoic and Cenozoic Eras.

  18. Periods Eras are divided into Periods. Ex. – the Mesozoic Era contains the Jurassic Period, the Cretaceous Period, and the Triassic Period.

  19. Chapter 17- The History of Life 17.1- The Fossil Record Index

  20. Macroevolution Large-scale evolutionary patterns and processes that occur over long periods of time.

  21. Types of Macroevolution • Extinction • Adaptive radiation • Convergent evolution • Coevolution • Punctuated equilibrium • Changes in developmental genes

  22. I. Extinction • Many paleontologists believe that mass extinctions were caused by several factors • No precise causes have been found yet.

  23. Mass extinctions have… • Provided ecological opportunities for organisms that survived • Resulted in bursts of evolution that produced many new species

  24. II. Adaptive Radiation • Process by which a single species or a small group evolves into several different forms that live in different ways • EX: Darwin’s finches- more than a dozen species evolved from a single species • Disappearance of dinosaurs resulted in the adaptive radiation of mammals

  25. III. Convergent Evolution • Unrelated organisms come to resemble one another • Undergo adaptive radiation in different places or at different times in similar environments • EX: sharks, dolphins, seals & penguins

  26. III. Coevolution • Two species evolve in response to changes in each other over time. • Organisms that are closely connected to one another by ecological interactions evolve together

  27. IV. Punctuated Equilibrium • Pattern of evolution in which long stable periods are interrupted by brief periods of rapid change. • Darwin-Biological change was slow & steady (gradualism)

  28. V. Developmental Genes & Body Plans • Changes in genes for growth & differentiation during embryological development could produce changes in body shape & size • Small changes in the activity of control genes can affect many other genes to produce large changes in adult animals.

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