1. Many types of evidence support evolution. Chapter 6 Section 4

2. The Fossil Record Preserved remains or traces of an organism that lived in the past Preserved remains or traces of an organism that lived in the past What Is A Fossil?

3. How Do MOST Fossils Form? An organism dies and becomes buried in sediment An organism dies and becomes buried in sediment

5. How Most Fossils Form

7. Then People Find Them!

8. What Do Fossils Reveal? Fossil record: millions of fossils that scientists have collected Fossil record: millions of fossils that scientists have collected Most of what we know about extinct species Most of what we know about extinct species Provides clues about how and when new groups of organisms evolved Provides clues about how and when new groups of organisms evolved Extinct: no members of the species are alive Extinct: no members of the species are alive

9. Fossils and Evolution Fossils!

10. Elephant Evolution

11. Elephant Evolution! Common Ancestor

13. Evidence for Evolution

14. Biological evidence supports evolution. State evidence from modern-day organisms that scientists use to show evolutionary relationships among groups. State evidence from modern-day organisms that scientists use to show evolutionary relationships among groups. Describe how scientists classify organisms and place them on branching trees. Describe how scientists classify organisms and place them on branching trees.

15. Vestigial Structures

16. Similarities in Body Structure homologous structures: similar structures that related species have inherited from a common ancestor homologous structures: similar structures that related species have inherited from a common ancestor Example: fish, amphibians, reptiles, birds & mammals all have an internal skeleton with a backbone Example: fish, amphibians, reptiles, birds & mammals all have an internal skeleton with a backbone

17. Homologous Structures

19. Similarities in Early Development embryos suggest common ancestor embryos suggest common ancestor Similar organisms go through similar stages in early development Similar organisms go through similar stages in early development Who is a closer relative: chickens and rats or chickens and turtles????? Who is a closer relative: chickens and rats or chickens and turtles????? Which Embryo Is Human?

22. Guess The Embryo! Try Your Luck!

24. Genetic Evidence: Similarities in DNA Related Species have many of the same nitrogen bases in common Related Species have many of the same nitrogen bases in common Compare order of amino acids in similar proteins Compare order of amino acids in similar proteins Elephant shrews – rodent or elephant???? Elephant shrews – rodent or elephant????

27. Golden-rumped sengi Rhynchocyon chrysopygus Weight = 550 g. Gedi Ruins, Kenya

28. The new species, named the gray-faced sengi (Rhynchocyon udzungwensis), weighs about 1.5 pounds, 25 percent larger than any other member of the elephant-shrew family. It is known to exist in only two groups in a 115-square-mile area of this largely unexplored forest. The new species, named the gray-faced sengi (Rhynchocyon udzungwensis), weighs about 1.5 pounds, 25 percent larger than any other member of the elephant-shrew family. It is known to exist in only two groups in a 115-square-mile area of this largely unexplored forest. Scientists report that its relatives include elephants, manatees, and the aardvark. In recent years, a number of other new species have been discovered here, including the Udzungwa partridge, a monkey known as the kipunji, and several amphibians and reptiles. Scientists report that its relatives include elephants, manatees, and the aardvark. In recent years, a number of other new species have been discovered here, including the Udzungwa partridge, a monkey known as the kipunji, and several amphibians and reptiles.

29. African Elephant ORDER: Proboscidea FAMILY: Elephantidae GENUS: Loxodonta SPECIES: africana

30. The Clock Gene – Circadian Rhythms

31. Our Family Tree

32. How Fast Does Evolution Occur? Fossil record is incomplete Fossil record is incomplete Fossils don’t always tell when something evolved Fossils don’t always tell when something evolved Some scientists think it occurs slow and steady Some scientists think it occurs slow and steady Some think it occurs in occasional rapid bursts Some think it occurs in occasional rapid bursts

33. Horses!

35. How Fast Does Evolution Occur? Usually find fossils unchanged for long periods of time Usually find fossils unchanged for long periods of time Fossils appear that are very different Fossils appear that are very different Explanation for lack of intermediate forms Fossil record incomplete Fossil record incomplete Assume that more forms will eventually be discovered Assume that more forms will eventually be discovered

36. How Fast Does Evolution Occur? Gradualism Slowly but steadily Slowly but steadily Tiny changes gradually add up to major changes over very long periods of time Tiny changes gradually add up to major changes over very long periods of time This is what Darwin thought This is what Darwin thought If correct, many intermediate forms for all species should exist If correct, many intermediate forms for all species should exist

37. How Fast Does Evolution Occur? Punctuated Equilibria Evolution occurs during short periods of rapid change Evolution occurs during short periods of rapid change Most new species form when small populations become isolated Most new species form when small populations become isolated Small, isolated populations can evolve quickly and adapt to new environment Small, isolated populations can evolve quickly and adapt to new environment Maybe as quick as a few hundred years Maybe as quick as a few hundred years Not many intermediate fossil forms would exist Not many intermediate fossil forms would exist Both seemed to have occurred Both seemed to have occurred