Lesson 3 The Mesozoic Era - MRS. ROUECHE - Home

Lesson 3The Mesozoic EraScan Lesson 3. Read the lesson titles and bold words. Look at the pictures. Identify three factsthat you discovered about the Mesozoic era. Record your facts in your Science Journal.Arrange the periods of the Mesozoic era in the table below.Geology of theMesozoic EraI found this on pagePeriods of the Mesozoic Era.fromI found this on pagemyatomyaOrganize information about the breakup of Pangaea.Pangaea began tobreak apart inI found this on pageSouthern continent:Northern continent:would become themodern continents ofwould become themodern continents ofSequence the events that formed the Atlantic Ocean.1. The climate wasduring the Mesozoic.rose.3. Pangaea began4.flowed onto5.the channels becameGeologic Time.formed.6. As continents508.,.The Mesozoic EraCopyright McGraw-Hill Education.2.

CHAPTER 17LESSON 3Geologic TimeThe Mesozoic EraKey ConceptsWhat do you think? Read the two statements below and decidewhether you agree or disagree with them. Place an A in the Before columnif you agree with the statement or a D if you disagree. After you’ve readthis lesson, reread the statements to see if you have changed your mind.BeforeStatementAfter What major geologicevents occurred duringthe Mesozoic era? What does fossil evidencereveal about the Mesozoicera?5. All large Mesozoic vertebrates were dinosaurs.6. Dinosaurs disappeared in a large massextinction event.3TUDY #OACHGeology of the Mesozoic EraWhen people imagine what Earth looked like millions ofyears ago, they often picture dinosaurs. Dinosaurs livedduring the Mesozoic era. This era of geologic time lastedfrom 251 mya to 65.5 mya. As shown in the figure below,the Mesozoic era is divided into three periods: the Triassic(tri A sihk), the Jurassic (joo RA sihk), and the Cretaceous(krih TAY shus).Make Flash Cards Changeeach main head into aquestion. Write each questionon one side of a small indexcard. Write the answer on theother side of the card. Quizyourself until you know all ofthe answers.Mesozoic EraCopyright McGraw-Hill Education.MesozoicPrecambrianPhanerozoic EonsErasVisual Check1. Name List the periodsof the Mesozoic era fromoldest to youngest.MesozoicCretaceousThe Mesozoic EraJurassicTriassic251 myaPeriods65.5 myaGeologic Time509

Breakup of PangaeaMake a shutter-fold book torecord information aboutchanges during the Mesozoicera.GeologyBiologyRecall that Pangaea was a supercontinent that formed atthe end of the Paleozoic era. Pangaea began to break apart inthe Late Triassic period. Eventually, Pangaea split into twolandmasses—Gondwanaland (gahn DWAH nuh land) andLaurasia (la RAY shzah).Gondwanaland was the southern continent. It includedthe future continents of Africa, Antarctica, Australia, andSouth America. Laurasia was the northern continent. Itincluded the future continents of North America, Europe,and Asia.Return of Shallow SeasMuch of Earth during the Mesozoic era was covered bylush, tropical forests and warm ocean waters. This is becausethe climate of the Mesozoic era was much warmer than theclimate of the Paleozoic era. Many species were adapted tothis type of environment. It was so warm that, for most ofthe Mesozoic era, there were no ice caps, even at the poles.With no glaciers, more water filled the oceans.Key Concept Check2. Explain When did theAtlantic Ocean begin to form?Some of this water flowed onto the continents as Pangaeabegan to split apart. This created narrow channels that grewlarger as the continents moved apart. Eventually, thechannels became oceans. The Atlantic Ocean began to format this time.The graph below shows the rise in sea level during theMesozoic era. Toward the end of the era, sea level was sohigh that inland seas covered much of Earth’s continents.These warm, shallow waters provided environments inwhich new organisms evolved.Sea Level Rise During MesozoicInterpret a Graph3. Identify In whichPresent sea levelTriassic510Geologic TimeJurassicCretaceousThe Mesozoic EraCopyright McGraw-Hill Education.period was sea level at itshighest?

Mesozoic North AmericaAlong North America’s eastern coast and the Gulf ofMexico, sea level rose and fell over millions of years. As thishappened, much seawater evaporated, leaving large saltdeposits behind. Some of these salt deposits are sources ofsalt today. Other salt deposits later became traps for oil.Today, salt traps in the Gulf of Mexico are an importantsource of oil.Throughout the Mesozoic era, the North Americancontinent moved slowly and steadily westward. Its westernedge collided with several small landmasses carried on anancient oceanic plate. As this plate subducted beneath theNorth American continent, the crust buckled inland, slowlypushing up the Rocky Mountains. In the dry Southwest,windblown sand formed huge dunes. In the middle of thecontinent, a warm inland sea formed.Mesozoic LifeThe species that survived the Permian mass extinctionevent lived in a world with few species. Vast amounts ofspace were open for animals and plants to inhabit. Newtypes of cone-bearing trees, such as pines and cycads, beganto appear. Toward the end of the Mesozoic era, the firstflowering plants evolved. The dinosaurs were the dominantvertebrates living on land. Hundreds of species existed.REVIEW VOCABULARYevaporatedchanged from liquid to gasKey Concept Check4. Explain How did theRocky Mountains form?DinosaursCopyright McGraw-Hill Education.Scientists today disagree about classifying dinosaurs asreptiles. Dinosaurs share a common ancestor with presentday reptiles, such as crocodiles. However, dinosaurs differfrom present-day reptiles in their hip structure. Dinosaurswere dominant Mesozoic land vertebrates that walked with legspositioned directly below their hips. This means that dinosaurswalked upright. In contrast, the legs of a crocodile stick outsideways from its body. As a result, a crocodile appears todrag itself along the ground.Scientists hypothesize that some dinosaurs are moreclosely related to present-day birds than they are to presentday reptiles. Some dinosaur fossils show evidence of afeathery covering. Archaeopteryx (ar kee AHP tuh rihks), forexample, was a small bird the size of a pigeon. It had wingsand feathers. It also had claws and teeth. Many scientistssuggest that it was an ancestor to birds. Future discoveriesmight help answer the question about why some dinosaursare more closely related to present-day birds than they are topresent-day reptiles.The Mesozoic Era5. Make ConnectionsWhich animals on Earthtoday are most closelyrelated to dinosaurs of theMesozoic era? (Circle thecorrect answer.)a. birdsb. mammalsc. reptilesGeologic Time511

Other Mesozoic VertebratesDinosaurs dominated the land during the Mesozoic era.But fossils show that other large vertebrates swam in theseas and flew in the air. Plesiosaurs (PLY zee oh sorz) wereMesozoic marine reptiles with small heads, long necks, and flippers.Through much of the Mesozoic, these reptiles dominatedthe oceans. Some were as long as 14 m.Key Concept Check6. Contrast How couldyou distinguish fossils ofplesiosaurs and pterosaursfrom fossils of dinosaurs?Other Mesozoic reptiles could fly. Pterosaurs (TER oh sorz)were Mesozoic flying reptiles with large, batlike wings. TheQuetzalcoatlus (kwetz oh koh AHT lus) was one of the largestpterosaurs. It had a wingspread of nearly 12 m. Thoughpterosaurs could fly, they were not birds. Recall that birds aremore closely related to dinosaurs.Appearance of MammalsDinosaurs and reptiles dominated the Mesozoic era, butanother type of vertebrate also lived during this time—mammals. Mammals evolved early in the Mesozoic era. Theywere small in size. Few were larger than present-day cats.Cretaceous Extinction Event7. Generalize How couldthe impact of a meteoritehelp cause a mass extinctionevent?The Mesozoic era ended 65.5 mya with a mass extinctioncalled the Cretaceous extinction event. Scientists proposethat a large meteorite impact was the main cause of thisextinction. This crash would have produced enough dust toblock sunlight for a long time. There is evidence thatvolcanoes also erupted at the same time. These eruptionswould have added more dust to the atmosphere. Withoutlight, plants died. Without plants, animals died. Dinosaurspecies and other large Mesozoic vertebrate species could notsurvive in the changed environment. They became extinct.Copyright McGraw-Hill Education.512Geologic TimeThe Mesozoic Era

Mini Glossarydinosaur: a dominant Mesozoic land vertebrate that walkedwith legs positioned directly below its hipspterosaur (TER oh sor): a Mesozoic flying reptile with large,batlike wingsplesiosaur (PLY zee oh sor): a Mesozoic marine reptile witha small head, long neck, and flippers1. Review the terms and their definitions in the Mini Glossary. Write a sentence describingone group of Mesozoic animals.2. In the center oval, list the similarities among the three groups shown.Dinosaurs lived on land closely related to birds Copyright McGraw-Hill Education. Plesiosaurs lived in seas had small heads, longnecks, and flippersPterosaurs flew through the air had large, batlike wingsWhat do you thinkReread the statements at the beginning of thelesson. Fill in the After column with an A if youagree with the statement or a D if you disagree.Did you change your mind?The Mesozoic EraConnect EDLog on to ConnectED.mcgraw-hill.comand access your textbook to find thislesson’s resources.END OFLESSONGeologic Time513

Lesson 3 The Mesozoic Era (continued)I found this on page.Categorize salt deposits in North America.Salt Depositssources ofleft whentodaysources oftodayI found this on pageExplain the geologic changes in North America during the.Mesozoic.North America moved westward andwith landmasses on an ancientIn the west the crust,.In the southwest In the middle of thecontinent a warmformedformed.forming the.Compare and contrast dinosaurs with modern crocodiles.Mesozoic LifeI found this on page. Both Modern Crocodile shared514Geologic TimeThe Mesozoic EraCopyright McGraw-Hill Education.Dinosaur

Lesson 3 The Mesozoic Era (continued)I found this on page.Compare and contrast the archaeopteryx with presentday birds.Archaeopteryx Modern BirdBoth beak I found this on page.Identify 3 types of Mesozoic reptiles.LandSeaAirI found this on page.Describe the size of Mesozoic mammals.I found this on page.Sequence the likely events of the Cretaceous extinctionevent.produceddust thatplantsCopyright McGraw-Hill Education.diedSummarize the overall evolution of life during the Mesozoic era.The Mesozoic EraGeologic Time515

Write the answer on the other side of the card. Quiz yourself until you know all of the answers. Visual Check 1. Name List the periods of the Mesozoic era from oldest to youngest. Mesozoic Era Eons Eras Periods Phanerozoic Mesozoic Cretaceous Jurassic Triassic Precambrian 251 mya 65.5 mya Mesozoic The Mesozoic Era Geologic Time The Mesozoic Era .