Reading Essentials for Biology Glencoe (794133), страница 43
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Read the terms and their definitions in the Mini Glossary above. Highlight the key termsthat apply to humans. Then choose one of the highlighted words and write a sentence usingthe word.________________________________________________________________________________________________________________________________________________________________________2. In each box write one important fact about the primate group named in that box.StrepsirrhinesHaplorhinesAnthropoidsOld World monkeysHominoidsNew World monkeysVisit the Glencoe Science Web site at science.glencoe.com to find yourbiology book and learn more about primate adaptation and evolution.178Chapter 16READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.PrimatesNameDateClassSection16.2 Human AncestrySC.D.1.4.4 The student knows that Earth’s systems and organisms are the result of a long, continuous changeover time.◗ Before You ReadIn the previous section you learned that chimpanzees are closely related to humans.
Yet there aremany things that humans can do that chimpanzees cannot do. On the lines below, list some of thethings that humans can do that other animals cannot do.________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________◗ Read to LearnCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.HominidsYou learned in the previous section that humans are part of aprimate group called the hominoids.
Hominoids (HAH mih noydz)are primates that can walk upright on two legs.This group includesgorillas, chimpanzees, bonobos, and humans.Some scientists suggest that the separation in the hominoid population is a result of environmental changes. These changes causedsome hominoid ancestors to leave the trees and move onto theground to find food. It may have been helpful to be bipedal, or ableto walk upright on two legs. Walking upright on two legs increasesspeed. It also leaves the arms and hands free for feeding, protecting young, and using tools.
This bipedal ability created a divisionof the hominoid group. Hominids (HAH mih nudz) are bipedalprimates that include modern humans and their direct ancestors.We learn about our hominid ancestors from the fossil record.While the record is incomplete, more and more hominid fossilsare found every year.IdentifyDetails Skim the section andhighlight the name of humanancestors (they appear in italics). Then say each name aloud.What discovery did Raymond Dart make?In 1924, Raymond Dart discovered a skull with an unusual feature. The skull had mostly apelike features but the opening in theskull for the spinal cord was in the same place as a human skull.The location of the opening, on the bottom of the skull, suggested that this hominoid walked upright. Dart classified theorganism as a new species of primate.
He called it Australopithecusafricanus (aw stray loh PIH thuh kus • a frih KAH nus), whichmeans “southern ape from Africa.”READING ESSENTIALSChapter 16179NameDateClassSection16.2Human Ancestry, continued1. What was different aboutthe skull Raymond Dartdiscovered?The skull has been dated to about 2.5 to 2.8 million years old.Since then, many more australopithecine fossils have been found.An australopithecine (ah stra loh PIH thuh sine) is an earlyhominid from Africa with both humanlike and apelike features.________________________Who is “Lucy”?________________________There are several different species of australopithecines.
“Lucy”is the most famous fossil of the Australopithecus afarensis species.Donald Johanson discovered Lucy’s skeleton in 1974. Lucy hasbeen dated to about 3.2 million years ago. Australopithecus afarensishad shoulders and arms that were apelike. The pelvis indicatesthey walked on two legs, or were bipedal, like humans. They hada small brain, similar to the apes.
Because of the combination ofapelike and humanlike features, it may be that Lucy and hominidslike her ate and slept as family groups in trees, but walked uprighton the ground to travel.Australopithecines disappeared between 2 and 2.5 millionyears ago. Some scientists suggest that they are the ancestors tomodern humans.________________________2. Who is “Lucy”?________________________________________________________________________Modern humans use tools and have a larger brain than australopithecines. When did hominids first begin to use tools? When didthe larger brain develop?What is Homo habilis?3. Analyze What is the significance of tool making?________________________________________________________________________180Chapter 16In 1964, Louis and Mary Leakey discovered skull pieces inTanzania, Africa.
This skull was more humanlike than those ofaustralopithecines. The braincase was larger, and the teeth andjaws were smaller, more like those of modern humans. TheLeakeys classified this new species with modern humans, in thegenus Homo. Simple stone tools were found near the fossil skull.Because of the tool-making ability they named the species Homohabilis, which means “handy human.” The fossils have been datedbetween 1.5 and 2.5 million years ago. Homo habilis is the earliestknown hominid to make and use stone tools. These tools suggestthat Homo habilis might have been a scavenger who used the stonetools to cut meat from dead bodies of animals that had been killedby other animals.READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.The Emergence of Modern HumansNameDateClassSection16.2Human Ancestry, continuedSome scientists propose that Homohabilis or another early hominid population gave rise to Homo erectus, a newhominid species that appeared 1.5 to1.8 million years ago.
Homo erectusmeans “upright human.” The face ofHomo erectus was more humanlike thanthat of Homo habilis. Evidence suggeststhat Homo erectus used fire, made stoneaxes, and lived in caves.The fossil pattern shows that Homoerectus migrated from Africa, spreadinginto Asia and possibly Europe, beforebecoming extinct between 130 000 and300 000 years ago.Copyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Where did Homo sapienscome from?Several hypotheses have been suggested to explain how modern humans,Homo sapiens, may have emerged. Thehypotheses were formed after studyingfossil bones and teeth, and the resultsof DNA studies.
The figure at theright illustrates a possible pathwayfor the evolution of Homo sapiens.A description of the most popularhypothesis follows.The fossil record shows that Homo sapiens appeared in Europe,Africa, the Middle East, and Asia about 100 000 to 500 000 yearsago. Two species are thought to have appeared before Homo sapiens.One is called Homo antecessor, the other is called Homo heidelbergensis (hi duhl berg EN sus). Scientists do not know which is thedirect ancestor to Homo sapiens. More studies will have to be completed. Both the earlier species had smaller teeth and larger brainsthan Homo erectus.READING ESSENTIALS4. What two speciesappeared before HomoSapiens?________________________________________________Chapter 16181NameDateClassSection16.2Human Ancestry, continuedYou may have heard of theNeandertals (nee AN dur tawlz).They were another early Homo species.Neandertals lived from 35 000 to 100000 years ago in Europe, Asia, and theMiddle East.
The brains of Neandertals were at least as large as the brainsof modern humans. Their bones werethicker than modern humans and theyhad larger faces. Neandertals lived incaves during the ice ages of their time.Scientists have found tools, carvedfigures, flowers, pollen, and other evidence that suggests that Neandertalsmay have communicated through aspoken language and had a religion.Could Neandertals have evolved into modern humans? Mostscientists think not.
The DNA and fossil evidence suggests thatNeandertals are a sister species of Homo sapiens called Cro-Magnon(kroh MAG nun). Both DNA evidence and fossil measurementsindicate that Cro-Magnon was more likely our direct ancestor. CroMagnons were identical to modern humans in height, skull structure, tooth structure, and brain size. They appeared about the sametime as Neandertals. Cro-Magnons were toolmakers and artists.There are also indications that they used language.
The illustration shown here is an example of a Cro-Magnon cave painting.182Chapter 16READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Who were the Neandertals?NameDateClassSection16.2Human Ancestry, continued◗ After You ReadMini Glossaryaustralopithecine (ah stra loh PIH thuh sine):early African hominid, genus Australopithecus, that had both apelike and humanlikecharacteristicsbipedal: ability to walk upright on two legs;leaves arms and hands free for other activities such as hunting, protecting young, andusing toolsCro-Magnon: species of Homo sapiens thatspread throughout Europe between 35 000to 40 000 years ago; were identical to modern humans in height, skull and tooth structure, and brain sizehominid (HAH mih nud): a group of bipedal primates that includes modern humans andtheir direct ancestorshominoid (HAH mih noyd): a group of primatesthat can walk upright on two legs; includesgorillas, chimpanzees, bonobos, and humansNeandertal (nee AN dur tawl): Homo speciesthat lived from 35 000 to 100 000 years agoin Europe, Asia, and the Middle East; hadthick bones and large faces with prominentnoses and brains at least as large as those ofmodern humans1.
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