2Chapter 14 The History of Life Section 1: Fossil Evidence of ChangeSection 2: The Origin of Life
3Earth formed about 4.6 billion years ago. Chapter 14The History of Life14.1 Fossil Evidence of ChangeLand EnvironmentsEarth formed about 4.6 billion years ago.Gravity pulled the densest elements to the center of the planet.After about 500 million years, a solid crust formed on the surface.
414.1 Fossil Evidence of Change Chapter 14The History of Life14.1 Fossil Evidence of ChangeAtmosphereThe gases that likely made up the atmosphere are those that were expelled by volcanoes.Water vapor (H2O)Carbon dioxide (CO2)Sulfur dioxide (SO2)Carbon monoxide (CO)Hydrogen sulfide (H2S)Hydrogen cyanide (HCN)Nitrogen (N2)Hydrogen (H2)
5A fossil is any preserved evidence of an organism. Chapter 14The History of Life14.1 Fossil Evidence of ChangeClues in RocksA fossil is any preserved evidence of an organism.Most organisms decompose before they have a chance to become fossilized.
614.1 Fossil Evidence of Change Chapter 14The History of Life14.1 Fossil Evidence of Change
8Nearly all fossils are formed in sedimentary rock. Chapter 14The History of Life14.1 Fossil Evidence of ChangeFossil FormationNearly all fossils are formed in sedimentary rock.The sediments build up until they cover the organism’s remains.Minerals replace the organic matter or fill the empty pore spaces of the organism.
9Chapter 14The History of Life14.1 Fossil Evidence of ChangeDating fossilsRelative dating is a method used to determine the age of rocks by comparing them with those in other layers.
10Uses the decay of radioactive isotopes to measure the age of a rock Chapter 14The History of Life14.1 Fossil Evidence of ChangeRadiometric DatingUses the decay of radioactive isotopes to measure the age of a rockRadioactive isotopes that can beused for radiometric dating are found only inigneous or metamorphic rocks.
11The Geologic Time Scale Chapter 14The History of Life14.1 Fossil Evidence of ChangeThe Geologic Time ScaleThe geological time scale is a model that expresses the major geological and biological events in Earth’s history.The geologic time scale is divided into the Precambrian time and the Phanerozoic eon.Eras of the Phanerozoic eon include the Paleozoic, Mesozoic, and Cenozoic eras.Each era is divided into one or more periods.
12Autotrophic prokaryotes enriched the atmosphere with oxygen. Chapter 14The History of Life14.1 Fossil Evidence of ChangePrecambrianNearly 90 percent of Earth’s entire history, stretching from the formation of Earth to the beginning of the Paleozoic era about 542 million years agoAutotrophic prokaryotes enriched the atmosphere with oxygen.
14The first tetrapods emerged in the Devonian. Chapter 14The History of Life14.1 Fossil Evidence of ChangeThe Paleozoic EraThe ancestors of most major animal groups diversified in what scientists call the Cambrian explosion.Life in the oceans continued to evolve at the end of the Cambrian period.Fish, land plants, and insects appeared during the Ordovician and Silurian periods.The first tetrapods emerged in the Devonian.
15Between 60 and 75 percent of the species alive went extinct. Chapter 14The History of Life14.1 Fossil Evidence of ChangeA mass extinction ended the Paleozoic era at the end of the Permian period.Between 60 and 75 percent of the species alive went extinct.
16About 65 million years ago, a meteorite struck Earth. Chapter 14The History of Life14.1 Fossil Evidence of ChangeThe Mesozoic EraMammals and dinosaurs first appeared late in the Triassic period, and flowering plants evolved from nonflowering plants.Birds evolved from a group of predatory dinosaurs in the middle of the Jurassic period.About 65 million years ago, a meteorite struck Earth.
17Chapter 14The History of Life14.1 Fossil Evidence of ChangePlate tectonics describes the movement of several large plates that make up the surface of Earth.These plates, some of which contain continents, move atop a partially molten layer of rock underneath them.
19Mammals became the dominant land animals. Chapter 14The History of Life14.1 Fossil Evidence of ChangeThe Cenozoic EraMammals became the dominant land animals.After the mass extinction at the end of the Mesozoic era, mammals of all kinds began to diversify.
20Spontaneous generation is the idea that life arises from nonlife. Chapter 14The History of Life14.2 The Origin of LifeOrigins: Early IdeasSpontaneous generation is the idea that life arises from nonlife.Francesco Redi, an Italian scientist, tested the idea that flies arose spontaneously from rotting meat.
21Chapter 14The History of Life14.2 The Origin of LifeThe theory of biogenesis states that only living organisms can produce other living organisms.Louis Pasteur designed an experiment to show that biogenesis was true even for microorganisms.
22Simple organic molecule formation Chapter 14The History of Life14.2 The Origin of LifeOrigins: Modern IdeasSimple organic molecule formationThe primordial soup hypothesis was an early hypothesis about the origin of life.Organic molecules could have been synthesized from simple reactions.UV light from the Sun and electric discharge in lightning might have been the primary energy sources.
23Chapter 14The History of Life14.2 The Origin of LifeStanley Miller and Harold Urey were the first to show that simple organic molecules could be made from inorganic compounds.Later, scientists found that hydrogen cyanide could be formed from even simpler molecules in simulated early Earth environments.
25Life requires proteins. Chapter 14The History of Life14.2 The Origin of LifeMaking ProteinsLife requires proteins.One possible mechanism for the formation of proteins would be if amino acids were bound to a clay particle.
26Some RNA sequences appear to have changed very little through time. Chapter 14The History of Life14.2 The Origin of LifeGenetic CodeSome RNA sequences appear to have changed very little through time.Many biologists consider RNA to have been life’s first coding system.Other researchers have proposed that clay crystals could have provided an initial template for RNA replication.
27Scientists hypothesize that the first cells were prokaryotes. Chapter 14The History of Life14.2 The Origin of LifeCellular EvolutionScientists hypothesize that the first cells were prokaryotes.Many scientists think that modern prokaryotes called archaea are the closest relatives of Earth’s first cells.
28Photosynthesizing Prokaryotes Chapter 14The History of Life14.2 The Origin of LifePhotosynthesizing ProkaryotesArchaea are autotrophic.They do not obtain their energy from the Sun.Archaea also do not need or produce oxygen.
29Chapter 14The History of Life14.2 The Origin of LifeMany scientists think that photosynthesizing prokaryotes evolved not long after the archaea.Prokaryotes, called cyanobacteria, have been found in rocks as old as 3.5 billion years.
30The Endosymbiont Theory Chapter 14The History of Life14.2 The Origin of LifeThe Endosymbiont TheoryThe ancestors of eukaryotic cells lived in association with prokaryotic cells.The relationship between the cells became mutually beneficial, and the prokaryotic symbionts became organelles in eukaryotic cells.This theory explains the origin of chloroplasts and mitochondria.
31Chapter 14The History of Life14.2 The Origin of Life
33Chapter Resource Menu Chapter Diagnostic Questions The History of LifeChapter Resource MenuChapter Diagnostic QuestionsFormative Test QuestionsChapter Assessment QuestionsStandardized Test Practicebiologygmh.comGlencoe Biology TransparenciesImage BankVocabularyAnimationClick on a hyperlink to view the corresponding feature.
34Which is an example of the theory of spontaneous generation? Chapter 14The History of LifeChapter Diagnostic QuestionsWhich is an example of the theory ofspontaneous generation?Tadpoles become frogs.A starfish can grow from a severed arm.Damp hay and corn create mice.From a tiny acorn, an oak can grow.ABCDCDQ 1
35What gas do scientists think was absent from Earth’s early atmosphere? Chapter 14The History of LifeChapter Diagnostic QuestionsWhat gas do scientists think was absent fromEarth’s early atmosphere?sulfurnitrogenoxygenwater vaporABCDCDQ 2
36In which period did the first land vertebrates appear? Chapter 14The History of LifeChapter Diagnostic QuestionsIn which period did the first land vertebratesappear?CambrianDevonianTriassicMesozoicABCDCDQ 3
37In which type of rock do paleontologists search for fossils? Chapter 14The History of Life14.1 Formative QuestionsIn which type of rock do paleontologists searchfor fossils?igneousmetamorphicsedimentaryvolcanicABCDFQ 1
38Which dating method determines the age of Chapter 14The History of Life14.1 Formative QuestionsWhich dating method determines the age ofrocks by comparing them to rocks in otherlayers?absolute datinggeological datingrelative datingsedimentary datingABCDFQ 2
39Which geological change during the Mesozoic Chapter 14The History of Life14.1 Formative QuestionsWhich geological change during the Mesozoicera had the greatest effect in shaping thecourse of evolution?plate tectonicsextensive glaciationincreased volcanic activitymeteorite impactABCDFQ 3
40At one time people believed that mold growing Chapter 14The History of Life14.2 Formative QuestionsAt one time people believed that mold growingon a piece of cheese was created by thecheese. This is the idea of __________.biogenesistransgenesisprimordial generationspontaneous generationABCDFQ 4
41According to the endosymbiont theory, what may Chapter 14The History of Life14.2 Formative QuestionsAccording to the endosymbiont theory, what mayhave happened to a prokaryotic cell that entereda host cell?It was digested by the host cell.It became an organelle in the host cell.It became a harmful parasite in the host cell.It was removed from the host cell by exocytosis.ABCDFQ 5
42An ancient prokaryote containing photosynthetic Chapter 14The History of Life14.2 Formative QuestionsAn ancient prokaryote containing photosyntheticpigments that was engulfed by a host cell mayhave become a _________.chloroplastlysosomecentrioleribosomeABCDFQ 6
43Which is the half-life of the radioactive isotope shown in the graph? Chapter 14The History of LifeChapter Assessment QuestionsWhich is the half-life of the radioactive isotope shown in the graph?18 years36 years54 years72 yearsABCDCAQ 1
44Study the graph. Determine the age of a rock if it contained 40% C-14. Chapter 14The History of LifeChapter Assessment QuestionsStudy the graph. Determine the age of a rock if it contained 40% C-14.2,857.5 years7,576 years11,460 years5,730 yearsABCDCAQ 2
45Which factor made it unlikely that life existed on Chapter 14The History of LifeStandardized Test PracticeWhich factor made it unlikely that life existed onEarth 4 billion years ago?absence of oxygenabsence of foodintense heatintense sunlightABCDSTP 1
46For which fossil might a paleontologist most Chapter 14The History of LifeStandardized Test PracticeFor which fossil might a paleontologist mostlikely use carbon-14 to determine its age?fossilized microbes in volcanic rockdinosaur footprints found in sedimentary rockmarine fossils found in a deep sedimentary layera woolly mammoth frozen in a glacier since the last Ice AgeABCDSTP 2
47Beryllium-10 (Be-10) has a half life of about Chapter 14The History of LifeStandardized Test PracticeBeryllium-10 (Be-10) has a half life of about1.5 million years. If a sample is analyzed anddetermined to contain ¼ of the original Be-10,what is the age of the sample?750,000 years3 million years4.5 million years6 million yearsABCDSTP 3
48Which provides the best evidence that a Chapter 14The History of LifeStandardized Test PracticeWhich provides the best evidence that ameteorite struck the earth 65 million yearsago?a large crater that was founda layer containing high levels of iridiumthe sudden appearance of mammalsthe sudden disappearance of dinosaursABCDSTP 4
49Standardized Test Practice Chapter 14The History of LifeStandardized Test PracticeIn this experiment using water and the gases to simulate Earth’s early atmosphere, which was not one of the final products?amino acidsnucleotidesRNA moleculessugar moleculesABCDSTP 5
50Chapter 14The History of LifeStandardized Test PracticeWhy do scientists believe that archea are the closest relatives to Earth’s first cells?They are eukaryotes.They contain DNA.They carry out photosynthesis.They live in extreme environments.ABCDSTP 6
51Glencoe Biology Transparencies Chapter 14The History of LifeGlencoe Biology Transparencies
53Section 1 Vocabulary fossil paleontologist relative dating Chapter 14The History of LifeVocabularySection 1fossilpaleontologistrelative datinglaw of superpositionradiometric datinghalf-lifegeologic time scaleeraperiodCambrian explosionK-T boundaryplate tectonics
54Section 2 Vocabulary spontaneous generation theory of biogenesis Chapter 14The History of LifeVocabularySection 2spontaneous generationtheory of biogenesisendosymbiont theory
55Visualizing Geologic Time Continental Drift Miller-Urey Experiment Chapter 14The History of LifeAnimationVisualizing Geologic TimeContinental DriftMiller-Urey ExperimentEndosymbiont Theory