1 / 21

C 14- The History of Life

C 14- The History of Life. Pp. 368- 391. Contents. 14-1 The Record of Life 14-2 The Origin of Life. 14-1 The Record of Life. Early earth probably hot with colliding meteorites & radioactive minerals By 4.4 BYA cooled enough for water to condense & lightening storms. History in Rocks.

hagen
Download Presentation

C 14- The History of Life

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. C 14- The History of Life Pp. 368- 391

  2. Contents • 14-1 The Record of Life • 14-2 The Origin of Life

  3. 14-1 The Record of Life • Early earth probably hot with colliding meteorites & radioactive minerals • By 4.4 BYA cooled enough for water to condense & lightening storms

  4. History in Rocks • Oldest rocks 3.9BY • Fossils offer clues to extinct life • 95% species extinct • Paleontologists study ancient life, climate, & geography

  5. Fossil Formation • Organisms are buried in sand, mud or clay & compressed & hardened into fossils.

  6. Relative Dating • Top layers are most recent while deeper layers are older.

  7. Radiometric Dating • Uses radioactive isotopes & half-life to determine age of rock or other organic matter

  8. A Trip Through Geologic Time • Geologic Time Scale • Divided into 4 large sections between mass extinctions • Earth formation 4.6BYA

  9. Precambrian Life • Resembled modern cyanobacteria • Stromatolites show existence of photosynthetic organisms early on • First prokaryotic life; later eukaryotic

  10. Diversity During Paleozoic • Cambrian explosion brought teeming ocean life • Fishes with backbones, ferns & seeded plants appeared • Amphibians & reptiles appear

  11. Life in the Mesozoic • Geologic changes • Early mammals appear during this age of reptiles • Birds evolve • Mass extinction of 2/3 species 65 MYA

  12. Changes During Mesozoic • Continental drift • Supercontinent broke up & drifted • Plate tectonics explains how the plates move • Affects climate change

  13. The Cenozoic Era • Age of mammals • Primate appear • Modern humans appear 200,000YA

  14. 14-2 The Origin of Life • Early ideas • Spontaneous generation- nonliving things produce life • Francesco Redi disproved this

  15. Pasteur’s Experiments • Louis Pasteur used a crook neck flask to boil a nutrient broth. Air could get in but microorganisms could not. • Biogenesis became accepted in biology after that.

  16. The Origin of Life • Modern Ideas • Simple organic molecules formed, then more complex molecules like protein, carbohydrates & nucleic acids • Alexander Oparin hypothesized life began in the ocean

  17. The Origin of Life • Stanley Miller & Harold Urey (1953) tested Oparin’s idea by simulating early conditions on Earth in the lab. • Amino acids, sugar & other small organic molecules were produced

  18. Formation of Protocells • Stanley Fox 1992 • Large ordered structure with a membrane that carries out some life activities such as growth and division

  19. The Evolution of Cells • Anaerobic prokaryotes • Heterotrophs • Autotrophs evolved • Archaebacteria prokaryotic extremophiles

  20. Photosynthesizing Prokaryotes • Release oxygen from water • Concentration of oxygen in atmosphere increases • Aerobes evolve • Ozone layer formed & allowing eukaryotes to evolve

  21. Endosymbiont Theory • Proposed by Lynn Margulis in 1960s • Eukaryotes evolved through a symbiotic relationship between prokaryotes • Chloroplasts & mitochondria have ribosomes

More Related