1. KEY CONCEPT Molecular clocks provide clues to evolutionary history.

2. Mutations add up at a fairly constant rate in the DNA of species that evolved from a common ancestor. Ten million years later— one mutation in each lineage Another ten million years later— one more mutation in each lineage Molecular clocks use mutations to estimate evolutionary time. Mutations add up at a constant rate in related species. This rate is the ticking of the molecular clock. As more time passes, there will be more mutations. The DNA sequences from two descendant species show mutations that have accumulated (black). The mutation rate of this sequence equals one mutation per ten million years. DNA sequence from a hypothetical ancestor

5. higher rate, better for studying closely related species

7. mutation rate ten times faster than nuclear DNA

9. many conservative regions

11. Plantae Animalia Classification is always a work in progress. Why? The tree of life shows our most current understanding. New discoveries can lead to changes in classification. Until 1866: only two kingdoms,Animalia and Plantae

14. 1938: prokaryotes moved to kingdom Monera

15. 1959: fungi moved to own kingdomMonera

17. 1938: prokaryotes moved to kingdom Monera

18. 1959: fungi moved to own kingdom

21. one of largest groups on Earth

23. cell walls chemically different from bacteria

24. differences discovered by studying RNA

27. kingdom Protista

29. kingdom Protista

30. kingdom Plantae

32. kingdom Protista

33. kingdom Plantae

34. kingdom Fungi

36. transfer genes among themselves outside of reproduction

37. blurs the linebetween “species”

39. Which of the following is not a feature of a cladogram? A. nodes B. derived characters C.clades D.taxons Correct Answer = D What is true about two organisms that share the same common ancestor? A. They have no common derived characters. B. They are in the same clade. C. They are not closely related. D. They evolved at the same time.

40. Which of the following is not a feature of a cladogram? A. nodes B. derived characters C.clades D.taxons Correct Answer = D What is true about two organisms that share the same common ancestor? A. They have no common derived characters. B. They are in the same clade. C. They are not closely related. D. They evolved at the same time. Correct Answer = B

41. Review DNA mutations give clues to evolutionary time and relationships Nuclear DNA, mitochondrial DNA and ribosomal RNA mutate at different rates As scientific discoveries were made, the number of kingdoms changed and domains were added