1. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. BIOLOGY A GUIDE TO THE NATURAL WORLD FOURTH EDITION DAVID KROGH A Slow Unfolding: The History of Life on Earth

2. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 19.1 The Geological Timescale: Life Marks Earth’s Ages

3. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Earth’s Geological Timescale Earth formed about 4.6 billion years ago, along with the rest of the universe http://www.youtube.co m/watch?v=5ItM53Rur n8

4. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Table 25-1a

5. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Table 25-1b

6. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Table 25-1

7. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Fig. 25-7 Animals Colonization of land Paleozoic Meso- zoic Humans Ceno- zoic Origin of solar system and Earth Prokaryotes Proterozoic Archaean Billions of years ago 1 4 3 2 Multicellular eukaryotes Single-celled eukaryotes Atmospheric oxygen

8. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Earth’s Geological Timescale Figure 19.4

9. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Earth’s Geological Timescale Life began on Earth about 3.8 billion years ago. Until about 1.2 billion years ago, all life was microscopic and single-celled.

10. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 19.2 How Did Life Begin?

11. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. How Did Life Begin? Life arose through a chemical process: –Simple elements and compounds available on the early Earth came together to produce more complex molecules. Ultimately, a group of these molecules became capable of self-replication.

12. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. “Prebiotic Soup” of Hot-Water Systems One hypothesis is that life began in a “prebiotic soup” of hot-water systems—in deep—sea vents or in hot-spring pools

13. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. “Prebiotic Soup” of Hot-Water Systems Other researchers life arose in the tide pools of Earth’s early oceans.

14. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The RNA World Critical question for origin-of-life researchers –Origin of the worker molecules called enzymes –And information-bearing molecules DNA and RNA Neither kind of molecule can be synthesized without the other.

15. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The RNA World Discovery of RNA molecules, called ribozymes that have enzymatic capabilities These molecules became capable of self-replication

16. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The RNA World Ribozymes provide evidence for an ancient “RNA world” –only living things were simple RNA molecules that could bring about their own replication.

17. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 19.3 The Tree of Life

18. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Tree of Life Figure 19.9 Domain Bacteria Domain Archaea Domain Bacteria Domain Archaea Domain Eukarya (Protists, Plants, Animals, Fungi) Kingdom Protista Kingdom Plantae Kingdom Animalia Kingdom Fungi gram- positive purple bacteria methane producers flowering plants evergreens ferns mosses diatoms dinoflagellates flagellates amoebae mushrooms vertebrates foram- inifera salt lovers hot acid lovers Universal ancestor cyano- bacteria inverte- brates yeast Life today began with a universal ancestor

19. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 19.4 A Long First Period: The Precambrian

20. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Precambrian The earliest evidence we have for life is recorded in rocks found in Greenland dated to about 3.8 billion years ago.

21. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Precambrian Figure 19.10

22. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Precambrian Fossils dating from 3.4 billion years ago, show that life was abundant. All of this life was bacterial and marine.

23. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Precambrian Figure 19.11

24. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Notable Precambrian Events Photosynthesis was first used by bacteria about 3.4 billion years ago. This was critical –photosynthesis provides the food for almost all life on Earth.

25. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Notable Precambrian Events Oxygen came to exist in significant quantity in Earth’s atmosphere by cyanobacteria carrying out photosynthesis This atmospheric oxygen was important for other living things

26. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 19.5 The Cambrian Explosion

27. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Cambrian Explosion “Cambrian Explosion” –a tremendous, rapid expansion in the number of animal forms –about 542 mya

28. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 19.6 The Movement onto the Land: Plants First

29. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Movement onto the Land Plants –evolved from green algae –gradual transition to land with their symbiotic partners, fungi

30. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Evolution of Plants Figure 19.15 Evolution of Plants mossesfernsconifersflowering plants Bryophytes Seedless vascular plants Angiosperms flowers seeds vascular tissue movement onto land green algae Gymnosperms Present 100 200 300 400 500 Millions of years ago Paleozoic Mesozoic Cenozoic BacteriaArchaea Protista Fungi Plantae Animalia

31. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Evolution of Plants Figure 19.16

32. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. 19.7 Animals Follow Plants onto the Land

33. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The First to Take Flight First land animals were arthropods A centipede-like creature Insects soon followed in great abundance. Arthropods were only land animals for millions of years.

34. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The First to Take Flight Figure 19.17

35. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Vertebrates onto Land Lobe-finned fishes gave rise to the four-limbed vertebrates, called tetrapods Moved onto land between 380 and 370 Mya.

36. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Vertebrates onto Land Figure 19.18 Ray-finned fishLobe-finned fishAmphibian

37. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Evolutionary Lines of Land Vertebrates Early tetrapods gave rise to amphibians-represented by today’s frogs and salamanders—that in turn gave rise to reptiles. All mammals then evolved from reptiles. Birds are the living descendents of the reptile branch that included the dinosaurs.

38. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Evolutionary Lines of Land Vertebrates Figure 19.20 Evolution of Terrestrial Vertebrates Lobe-finned fish AmphibiansReptiles Dinosaurs BirdsMammals invertebrate ancestors ancestral vertebrates movement onto land amniotic egg mammary glands hair jawed fish Present 100 200 300 400 500 600 Millions of years ago Paleozoic Mesozoic Cenozoic acorn worm sea squirts amphioxus vertebrates

39. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. Evolutionary Lines of Land Vertebrates All of today’s basic forms of animals evolved by 75 Mya –10 million years before extinction of dinosaurs in the Cretaceous Extinction.

40. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Primates The order of mammals called primates has fossils that date from 55 Mya. Large, front-facing eyes, limbs with an opposable first digit (thumbs in today’s human beings), and a tree-dwelling existence (which some later-arriving primates lost).

41. Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings. The Primate Mammals Figure 19.21