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Meet Lucy!

Meet Lucy!. Lucy is a fossil of Australopithecus afarensis (early form of human) that was discovered in 1974 in Ethiopia. Estimated to have lived about 3.2 million years ago!. What does Lucy tell us about the evolution of humans?.

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Meet Lucy!

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  1. Meet Lucy! Lucy is a fossil of Australopithecus afarensis(early form of human) that was discovered in 1974 in Ethiopia. Estimated to have lived about 3.2 million years ago!

  2. What does Lucy tell us about the evolution of humans? • Scientists think Lucy was about 3 feet and 7 inches tall, 64 lbs., and looked like the common chimpanzee. • Lucy showed scientists that humans evolved bipedalism before they evolved large brains.

  3. Why do we care? • If today’s species came from ancient species, then we should be able to find remains of those species that no longer exist. • Fossils help us to learn more about where species came from, how they evolved, and why species evolved certain characteristics. Fun Fact! The chicken is the closest living relative to the T-Rex dinosaur!

  4. Evidence of Evolution includes The Fossil Record Geographic Distribution of Living Species Homologous Body Structures Similaritiesin Early Development which is composed of which indicates which implies which implies physical remains of organisms common ancestral species similar genes similar genes Evidence of Evolution

  5. The Fossil Record

  6. What conclusion can you draw from this information? • Rhea – native to South America • Ostrich – native to Africa • Emu – native to Australia

  7. The Geographic Distribution of Living Things • Can indicate similar structures forming due to similar habitats (& therefore similar selective pressures)

  8. The Geographic Distribution of Living Things • OR can indicate common ancestry from fossil forms that occupy a continuous area

  9. What does the fossil record show us? • Evidence of an old Earth • Allows us to explore the morphology of organisms from the past

  10. What does the fossil record show us? • Species once existed & are now extinct • Transitional Forms: fossils or organisms that show the intermediate states between an ancestral form & that of its descendants

  11. Within the fossil record, you can see different rates of change… • Gradualism: slight changes within a population over time (subtle) • Punctuated Equilibrium: a quick change in population (dramatic – indicates a major event) • Stasis: the idea that during periods of time, little if any change is observed within a population (none)

  12. A. GradualismB. Punctuated EquilibriumC. Stasis Gradualism!

  13. A. GradualismB. Punctuated EquilibriumC. Stasis Punctuated Equilibrium!

  14. A. GradualismB. Punctuated EquilibriumC. Stasis Stasis!

  15. How are fossils formed?

  16. Fossil Formation • Fossils can be as large & complete as an entire, perfectly preserved animal, or small & incomplete as a tiny fragment of a jawbone or leaf! • There are fossil eggs, footprints, & even animal droppings. • For a fossil to form, either the remains of the organism or some traces of its presence must be preserved. • For every organism that leaves a fossil, many more die without leaving a trace.

  17. How can we tell how old fossils are? • Scientists use two ways to estimate the age of fossils: • Relative Dating • Radioactive Dating

  18. Relative Dating • Estimate age using the layers of fossils • Old fossils are found below new fossils! • Living organisms may resemble fossils, but differences may be evident.

  19. Which layer is the oldest? Which layer is the youngest? Oldest = F, Youngest = A Do the layers support the idea that change has occurred over a long period of time? Yes, water to desert conditions! What might have happened from layer C to layer B? Erosion

  20. Radioactive Dating • Using carbon dating on rocks & fossils to determine a more accurate time frame in which the organism lived We know how long it takes for radioactive carbon to decay. By identifying how much is left in a fossil, we can give it an age.

  21. Which is more accurate? • Relative Dating • Radioactive Dating Radioactive Dating!

  22. A scientist finds fossils of pine branches, birds, and deer-like animals. This area was at one time most likely a… • Forest • Ocean • Desert • Tropical Rainforest Forest!

  23. Is it easy reconstructing fossils? • When a fossil is discovered, rarely is it of a complete organism. • More often, paleontologists must reconstruct an extinct species from a few fossil pieces. • When they study a fossil, they look for anatomical similarities between the fossil & living organisms.

  24. Is it easy reconstructing fossils? • Imagine you are a paleontologist! During your excavation, you find fossil pieces. • With your team, try to put the whole fossil together.

  25. Can you tell what this organism’s closest living relative is?

  26. Ambulocetusnatans Ambulocetusnatansis the ancestor of the whale!

  27. By observing fossils of the Ambulocetusnatans, what can we tell about the evolution/history of the whale?

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