Chapter 17

1. Chapter 17 The History of Life

2. Things to know from Sec. 1 • Fossil record • Relative dating • Radioactive dating • ½ life • Main divisions of geological time scale

3. Age of fossil with respect to another rock or fossil (that is, older or younger) Age of a fossil in years Comparing depth of a fossil’s source stratum to the position of a reference fossil or rock Determining the relative amounts of a radioactive isotope and nonradioactive isotope in a specimen Imprecision and limitations of age data Difficulty of radioassay laboratory methods Compare/Contrast Table Section 17-1 Comparing Relative and Absolute Dating of Fossils Relative Dating Absolute Dating Can determine Is performed by Drawbacks Go to Section:

4. Figure 17-2 Formation of a Fossil Section 17-1 Water carries small rock particles to lakes and seas. Dead organisms are buried by layers of sediment, which forms new rock. The preserved remains may later be discovered and studied. Go to Section:

5. Notes from Section 2 • How did the Earth form? • What are the first organic molecules? • How did life begin? • What is free oxygen? • What is the origin of eukaryotic cells? • How did the rise of sexual reproduction and multicellularity speed up evolutionary change?

6. Things to know from Sec. 2 • Earth’s early atmosphere gases • Endosymbiotic theory • Common day mitochondria may have come from early prokaroyotes

7. Concept Map Section 17-2 Evolution of Life Early Earth was hot; atmosphere contained poisonous gases. Earth cooled and oceans condensed. Simple organic molecules may have formed in the oceans.. Small sequences of RNA may have formed and replicated. First prokaryotes may have formed when RNA or DNA was enclosed in microspheres. Later prokaryotes were photosynthetic and produced oxygen. An oxygenated atmosphere capped by the ozone layer protected Earth. First eukaryotes may have been communities of prokaryotes. Multicellular eukaryotes evolved. Sexual reproduction increased genetic variability, hastening evolution. Go to Section:

8. Section 17-2 Mixture of gases simulating atmospheres of early Earth Spark simulating lightning storms Cold water cools chamber, causing droplets to form Condensation chamber Water vapor Liquid containing amino acids and other organic compounds Go to Section:

9. Section 17-2 Chloroplast Plants and plantlike protists Aerobic bacteria Ancient Prokaryotes Photosynthetic bacteria Nuclear envelope evolving Mitochondrion Primitive Photosynthetic Eukaryote Animals, fungi, and non-plantlike protists Primitive Aerobic Eukaryote Ancient Anaerobic Prokaryote Go to Section:

10. Figure 17-5 Geologic Time Scale Section 17-1 (millions of years ago) (millions of years ago) Era Period Time (millions of years ago) Era Period Time Era Period Time Permian Carboniferous Devonian Silurian Ordovician Cambrian 290 – 245 363–290 410–363 440–410 505–440 544–505 Quarternary Tertiary Cretaceous Jurassic Triassic 1.8–present 65–1.8 145–65 208–145 245–208 Vendian 650–544 Go to Section:

11. Figure 17-5 Geologic Time Scale Section 17-1 (millions of years ago) (millions of years ago) Era Period Time (millions of years ago) Era Period Time Era Period Time Permian Carboniferous Devonian Silurian Ordovician Cambrian 290 – 245 363–290 410–363 440–410 505–440 544–505 Quarternary Tertiary Cretaceous Jurassic Triassic 1.8–present 65–1.8 145–65 208–145 245–208 Vendian 650–544 Go to Section:

12. Figure 17-5 Geologic Time Scale Section 17-1 (millions of years ago) (millions of years ago) Era Period Time (millions of years ago) Era Period Time Era Period Time Permian Carboniferous Devonian Silurian Ordovician Cambrian 290 – 245 363–290 410–363 440–410 505–440 544–505 Quarternary Tertiary Cretaceous Jurassic Triassic 1.8–present 65–1.8 145–65 208–145 245–208 Vendian 650–544 Go to Section:

13. Things to know from Sec. 3 • Devonian Period – Age of Fishes and rise of early land “animals” • Carboniferous Period – large amounts of plants that gives us our fossil fuels of today • Mesozoic Era – increase dominance of dinosaurs and appearance of flowering plants

14. Sec. 3 con’t • Triassic Period – Age of Reptiles • Cenozoic Era- Age of Mammals • Quaternary Period – rise of Homo sapiens

15. Geologic Time Scale with Key Events Section 17-3 (millions of years ago) Era Period Time Key Events Cenozoic Mesozoic Paleozoic Precambrian Time Quaternary Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian 1.8–present 65–1.8 145–65 208–145 245–208 290–245 363–290 410–363 440–410 505–440 544–505 650–544 Glaciations; mammals increased; humans Mammals diversified; grasses Aquatic reptiles diversified; flowering plants; mass extinction Dinosaurs diversified; birds Dinosaurs; small mammals; cone-bearing plants Reptiles diversified; seed plants; mass extinction Reptiles; winged insects diversified; coal swamps Fishes diversified; land vertebrates (primitive amphibians) Land plants; land animals (arthropods) Aquatic arthropods; mollusks; vertebrates (jawless fishes) Marine invertebrates diversified; most animal phyla evolved Anaerobic, then photosynthetic prokaryotes; eukaryotes, then multicellular life Go to Section:

16. Things to know from Sec. 4 • Macroevolution – large scale evolutionary changes that take place over long period of time • 1) Mass extinctions • 2) Adaptive radiation • 3) Convergent evolution • 4) Coevolution • 5) Punctuated equillibrium • 6) Changes in developmental genes

17. Mass extinctions • More than 99% of all species are now extinct • Usually happens at a constant rate • Could be one major event or a series of events

18. Adaptive radiation • Occurs when a single species or a small group has evolved into different forms that live in different ways • Example: Rise of mammals p.436 chart

19. Convergent evolution • Process by which unrelated organisms resemble each other • Example: sharks and dolphins

20. Coevolution • Process in which 2 species evolve in response to changes in each other over time • Example: Hawk moth and orchid from p.438

21. Punctuated evolution • Describes evolution that takes place over long, stable periods of time interrupted by brief periods of more rapid change • Example: Horse evolution • Gradualism vs. Punctuated evolution

22. Changes in development genes • Hox genes (“master control genes”) – control growth as an embryo develops • Some hox genes control which parts become top, bottom, front, & rear • While others control growth of body parts • Look at p. 440

23. Unrelated Related Intense environmental pressure Similar environments Inter-relationshiops Small populations Different environments Convergent evolution Punctuated equilibrium Adaptive radiation Coevolution Extinction Flowchart Section 17-4 Species that are form in under under in in can undergo can undergo can undergo can undergo can undergo Go to Section: