Updated July 2005 Created by C. Ippolito July 2005 Chapter 17 The History of Life The Fossil Record (pp ) Earth’s Early History (pp ) Evolution of Multicellular Life (pp ) Patterns of Evolution (pp

Updated July 2005 Created by C. Ippolito July 2005 Chapter 17 Section 1 The Fossil Record Objectives: Describe the fossil record. State the information that relative dating and radioactive dating provide about fossils Identify the divisions of the geological time scale.

Updated July 2005Created by C. Ippolito July 2005 Fossils and Ancient Life Paleontologists Paleontologists Scientists who collect and study fossils Scientists who collect and study fossils Structure of organisms Structure of organisms What organisms ate What organisms ate Who ate them Who ate them Environment lived in Environment lived in Fossil Record Fossil Record All information inferred by study of fossils All information inferred by study of fossils Evidence of the history of life on Earth Evidence of the history of life on Earth How groups of organisms changed over time How groups of organisms changed over time

Updated July 2005Created by C. Ippolito July 2005 How Fossils Form Fossils form in sedimentary rock Fossils form in sedimentary rock Rock exposed to rain, heat, wind, and cold breaks into small particles Rock exposed to rain, heat, wind, and cold breaks into small particles Particles settle to the bottom in layers Particles settle to the bottom in layers Fossils form when: Fossils form when: Particles cover remains of dead organism Particles cover remains of dead organism imprint left in rock after decay (imprint) imprint left in rock after decay (imprint) hard parts replaced by minerals (petrifaction) hard parts replaced by minerals (petrifaction) complete cover before decay by fine particles (mold) complete cover before decay by fine particles (mold) Body caught in plant resin (amber) Body caught in plant resin (amber)

Updated July 2005Created by C. Ippolito July 2005 Types of Fossils Mold Fossils Mold Fossils Imprint Fossil Imprint Fossil Petrified Fossil Petrified Fossil Fossil in Amber Fossil in Amber

Updated July 2005Created by C. Ippolito July 2005 Interpreting Fossil Evidence Two ways to determine age of fossil: Two ways to determine age of fossil: 1. Relative Dating – age compared to other fossils Sedimentary rock forms in layers Sedimentary rock forms in layers Oldest in lower layers Oldest in lower layers More recent in upper layers More recent in upper layers Index Fossils Index Fossils Short lived Short lived Found in specific layers Found in specific layers 2. Radioactive Dating – age calculated based on amount radioisotopes found in sample Half-life – time for half of radioisotope to decay Half-life – time for half of radioisotope to decay Carbon years Carbon years Potassium billion years Potassium billion years

Updated July 2005Created by C. Ippolito July 2005 Geological Time Scale Developed to represent evolutionary time Developed to represent evolutionary time Precambrian Time – Big Bang to first multicellular life forms (88% of time) Precambrian Time – Big Bang to first multicellular life forms (88% of time) Eras Eras Paleozoic – vertebrates & invertebrate life Paleozoic – vertebrates & invertebrate life Mesozoic – age of dinosaurs Mesozoic – age of dinosaurs Cenozoic – age of mammals Cenozoic – age of mammals Periods Periods Smaller subdivisions of the eras Smaller subdivisions of the eras

Updated July 2005Created by C. Ippolito July 2005 Geological Time Scale If we consider time scale as 24 hours: If we consider time scale as 24 hours:

Updated July 2005 Created by C. Ippolito July 2005 Homework Section Assessment 17-1 on page 422 (1 thru 4) and Checkpoints on pages 418 and 420

Updated July 2005 Created by C. Ippolito July 2005 Chapter 17 Section 2 Earth’s Early History Objectives: Describe how conditions on early Earth were different from conditions today. Explain what Miller and Urey’s experiments showed. State the hypotheses that have been proposed for how life first arose on Earth. Identify some of the main evolutionary steps in the early evolution of life.

Updated July 2005Created by C. Ippolito July 2005 Formation of Earth Post Big Bang cosmic debris attracted together over 100 million years Post Big Bang cosmic debris attracted together over 100 million years As surface cooled molten material  crust; then oceans As surface cooled molten material  crust; then oceans Surface broken by many volcanoes Surface broken by many volcanoes Early Atmosphere – very different gases Early Atmosphere – very different gases 1. hydrogen cyanide (HCN) 2. carbon dioxide (CO 2 ) 3. carbon monoxide (CO) 4. nitrogen (N 2 ) 5. hydrogen sulfide (H 2 S) 6. water (H 2 O)

Updated July 2005Created by C. Ippolito July 2005 First Organic Molecules Urey Miller Experiment Urey Miller Experiment Lab simulation of early atmosphere Lab simulation of early atmosphere Gases Gases methane (CH 4 ) methane (CH 4 ) ammonia (NH 3 ) ammonia (NH 3 ) water (H 2 O) water (H 2 O) Energy Energy Spark (lightning) Spark (lightning) Heat (Bunsen burner) Heat (Bunsen burner) Radiation (sun lamps) Radiation (sun lamps) Result Result Water contained amino acids and simple sugars Water contained amino acids and simple sugars

Updated July 2005Created by C. Ippolito July 2005 How Did Life Begin? Formation of Microspheres Formation of Microspheres Sidney Fox Experiment Sidney Fox Experiment Clusters of proteins form cell-like structures (a.k.a coacervates or proteinoids) Clusters of proteins form cell-like structures (a.k.a coacervates or proteinoids) Some may contain “enzymes” Some may contain “enzymes” Evolution of DNA and RNA Evolution of DNA and RNA Origin unknown some hypothesis include various ways of self replication Origin unknown some hypothesis include various ways of self replication

Updated July 2005Created by C. Ippolito July 2005 Free Oxygen Microfossils – prokaryotic cells Microfossils – prokaryotic cells Appear to be similar to modern bacteria Appear to be similar to modern bacteria Anaerobic Respiration Life Anaerobic Respiration Life Lack of free oxygen in atmosphere Lack of free oxygen in atmosphere Used nutrients in oceans and add carbon dioxide Used nutrients in oceans and add carbon dioxide Photosynthetic Life Photosynthetic Life Primitive photosynthetic bacteria Primitive photosynthetic bacteria Make own food and add free oxygen Make own food and add free oxygen Aerobic Respiration Life Aerobic Respiration Life Free oxygen allows more frugal use of nutrients Free oxygen allows more frugal use of nutrients

Updated July 2005Created by C. Ippolito July 2005 Origin of Eukaryotic Cells Endosymbiotic Theory Endosymbiotic Theory Proposed by Lynn Margulis Proposed by Lynn Margulis Eukaryotic cells with organelles formed from communities of prokaryotic cells Eukaryotic cells with organelles formed from communities of prokaryotic cells DNA in mitochondria and chloroplasts DNA in mitochondria and chloroplasts

Updated July 2005 Created by C. Ippolito July 2005 Homework Section Assessment 17-2 on page 428 (1 thru 5) and Checkpoints on page 424 and 426

Updated July 2005 Created by C. Ippolito July 2005 Chapter 17 Section 3 Evolution of Multicellular Life Objectives: Describe the key forms of life in the Paleozoic, Mesozoic, and Cenozoic Eras.

Updated July 2005Created by C. Ippolito July 2005 Precambrian Time Longest period of Earth’s history Longest period of Earth’s history Prokaryotic cells Prokaryotic cells Anaerobic Anaerobic Photosynthetic Photosynthetic Aerobic Aerobic Eukaryotic Cells Eukaryotic Cells Soft Bodied Multicellular Organisms Soft Bodied Multicellular Organisms

Updated July 2005Created by C. Ippolito July 2005 Paleozoic Era Rapid evolution of marine life Rapid evolution of marine life Cambrian Period Cambrian Period Invertebrates – jellyfish, worms, sponges Invertebrates – jellyfish, worms, sponges Shelled – clam and mussel ancestors Shelled – clam and mussel ancestors Exoskeleton – Trilobites Exoskeleton – Trilobites Ordovician and Silurian Periods Ordovician and Silurian Periods Invertebrates – octopi, squid, insects Invertebrates – octopi, squid, insects Land Plants Land Plants Vertebrates – jawless fish Vertebrates – jawless fish Devonian Period Devonian Period Ferns Ferns Fish – sharks, bony fish with scales Fish – sharks, bony fish with scales Land Animals - amphibians Land Animals - amphibians Carboniferous and Permian Periods Carboniferous and Permian Periods Land Animals – reptiles and winged insects Land Animals – reptiles and winged insects FIRST MASS EXTINCTION occurs – most marine organisms die out FIRST MASS EXTINCTION occurs – most marine organisms die out

Updated July 2005Created by C. Ippolito July 2005 Mesozoic Era Age of Dinosaurs Age of Dinosaurs Flowering Plants appear Flowering Plants appear Triassic Period Triassic Period First dinosaurs First dinosaurs Small mammals Small mammals Jurassic Period Jurassic Period Dinosaurs dominant Dinosaurs dominant Archaeopteryx – first bird Archaeopteryx – first bird Cretaceous Cretaceous T. Rex dominant T. Rex dominant Flowering plants Flowering plants SECOND MASS EXTINCTION occurs – 50% of organisms die out – all of dinosaurs SECOND MASS EXTINCTION occurs – 50% of organisms die out – all of dinosaurs

Updated July 2005Created by C. Ippolito July 2005 Cenozoic Era Age of Mammals Age of Mammals Tertiary Period Tertiary Period Grasses evolve Grasses evolve Large grazing mammals and birds Large grazing mammals and birds Quaternary Period Quaternary Period Multiple Ice Ages and Glacial Movements Multiple Ice Ages and Glacial Movements Man appears at end Man appears at end

Updated July 2005 Created by C. Ippolito July 2005 Homework Section Assessment 17-3 on page 434 (1 thru 4) and Checkpoints on pages 430 and 432

Updated July 2005 Created by C. Ippolito July 2005 Chapter 16 Section 4 Patterns of Evolution Objectives: Identify important patterns of macroevolution.

Updated July 2005Created by C. Ippolito July 2005 Macroevolution Large scale evolutionary changes that occurred over long periods of time Large scale evolutionary changes that occurred over long periods of time Mass Extinction Mass Extinction Permian – volcanic activity and shifting continents Permian – volcanic activity and shifting continents Cretaceous – asteroid collision in Caribbean Ocean Cretaceous – asteroid collision in Caribbean Ocean Adaptive Radiation Adaptive Radiation One ancestral form changes in to many different form to take advantage of adaptations (finches) One ancestral form changes in to many different form to take advantage of adaptations (finches)

Updated July 2005Created by C. Ippolito July 2005 Convergent Evolution Natural selection causes unrelated species to resemble one another. Natural selection causes unrelated species to resemble one another. Analogous structures are produced by convergent evolution. Analogous structures are produced by convergent evolution. bandicoot rat

Updated July 2005Created by C. Ippolito July 2005 Coevolution Two or more species evolve in response to each other through cooperative or competitive adaptations Two or more species evolve in response to each other through cooperative or competitive adaptations

Updated July 2005Created by C. Ippolito July 2005 Rate of Evolution Gradualism - species arise slowly and continuously as changes accumulate over millions of years Gradualism - species arise slowly and continuously as changes accumulate over millions of years Punctuated Equilibrium - species stay same for long periods and change abruptly by spurts of rapid evolution Punctuated Equilibrium - species stay same for long periods and change abruptly by spurts of rapid evolution

Updated July 2005 Created by C. Ippolito July 2005 Homework Section Assessment 16-4 on page 440 (1 thru 5) and Checkpoints on pages 437 and 438