Reading Essentials for Biology Glencoe (794133), страница 44
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Read the terms and their definitions in the Mini Glossary above. Circle the three key termsthat identify particular early hominid species.Copyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.2. Use the table below to help you review what you have read. In the second column list thecharacteristics of the hominid species described in the first column.Australopithecines3 to 4 million years agoCharacteristics:Homo habilis, Homo erectus1.5 to 2 million years agoCharacteristics:Neandertals35 000 to 100 000 years agoCharacteristics:Cro-Magnons35 000 to 40 000 years agoCharacteristics:Visit the Glencoe Science Web site at science.glencoe.com to findyour biology book and learn more about human ancestry.READING ESSENTIALSChapter 16183NameDateClassSection17.1 Classification◗ Before You ReadThis section explains how scientists have organized the study of living things.
This organizationmakes it easy to tell which organisms share characteristics and which are related to each other. Howorganized are you? Do you organize your clothes or CD collection? On the lines below, describe theadvantages of being organized.______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________◗ Read to LearnCreate a Quiz After youhave read this section, createa five-question quiz based onwhat you have learned.
Afteryou have written the questions, be sure to answer them.1. What is taxonomy?________________________________________________________________________184Chapter 17Organizing items not only makes them easier to find, it can alsomake them easier to understand. One tool biologists use to organize and understand living organisms is classification. Classificationis the grouping of objects or information based on similarities.The branch of biology that groups and names organisms based ontheir characteristics is called taxonomy (tak SAH nuh mee).Hundreds of years ago, the Greek philosopher Aristotle developed the first widely accepted biological classification systems.He started with two groups, plants and animals.
Then he dividedplants into three groups, herbs, shrubs, and trees depending onsize and structure. He divided animals into groups according tocharacteristics such as physical differences and habitat or wherethey lived. Aristotle’s system was useful for a while. But he hadgrouped together some organisms that really had very little incommon. For example, he grouped birds, bats, and flying insectstogether because they could fly.In the early 1700s, Carolus Linnaeus developed a system ofclassifying organisms that is still used today.
Linnaeus based hissystem on physical and structural similarities of organisms. Forexample, he classified plants according to their flower structures.This method of classifying showed the relationships of organisms.READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.How Classification BeganNameDateClassSection17.1Classification, continuedHow are species identified?Linnaeus developed a two-word naming system called binomialnomenclature. This system identifies specific species. The firstword identifies the genus. A genus (JEE nus; plural, genera) is agroup of similar species.
The second word is called the specificepithet, which often describes a characteristic of the organism.The species name is made up of both the genus name and the specific epithet. For example, the species name for modern humansis Homo sapiens. Homo is the name of the genus humans are in.Sapiens is a Latin word for “wise.”2. In the species nameHomo sapiens, what isthe genus? What is thespecific epithet?________________________________________________________________________Modern ClassificationScientists who study taxonomy are called taxonomists.
They tryto identify and classify organisms based on a number of things.These include the external and internal structures of the organismas well as where the organism lives. Taxonomists also consider thegenetic makeup of organisms to reveal their evolutionary relationships to other organisms.Copyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.What are some uses of taxonomy?Classification gives biologists a framework that allows them tostudy the relationships between living and extinct organisms.
Forexample, this framework allows biologists to study the relationship between birds and dinosaurs.Biologists have found that the bones of some dinosaurs havelarge internal spaces. So do the bones of birds. Dinosaur and birdskeletons have other similarities. Because of these findings, somebiologists believe that dinosaurs are more closely related to birdsthan to reptiles.Taxonomy can be a useful tool for scientists who work in suchareas as agriculture, forestry, and medicine. For example, a childmight eat berries from a plant in his or her backyard.
The parentswould rush the child and a sample of the plant to the hospital. A scientist in the poison control center could identify the plant and thedoctors would then determine what treatment might be necessary.Taxonomy can also help the economy. Taxonomists can discover new sources of lumber, medicines, and energy. For example,a taxonomist might know that a certain species of pine tree contains chemicals that make good disinfectants.
It is possible that aclosely related pine species could have the same useful substances.So instead of having one source of chemicals, there may betwo sources.READING ESSENTIALS3. Apply For which of thefollowing could taxonomy be used? (Circle yourchoice.)a. to determine whethera plant is safe to beplanted in a schoolyardb. to find a new sourcefor a medicine thatcomes from plantsc. both a.
and b.d. neither a. or b.Chapter 17185NameDateClassSection17.1Classification, continuedHow Living Things Are Classified________________________________________________________________________What are the different taxonomic groups?KingdomAnimaliaPhylumChordataClassMammaliaOrderOrderCarnivoraRodentiaFamilyFamilyProcyonidaeCaviidaeGenusGenusProcyonCaviaSpeciesSpeciesProcyonlotorCaviaporcellusAs you can see from the figure to the left, a speciesis the most specific group.
A genus is a group of similar species. A family is a taxon of similar genera. Anorder is a taxon of similar families. A class is a taxonof similar orders. A phylum is a taxon of similarclasses. (Plant taxonomists use the taxon divisioninstead of phylum.) A kingdom is a taxon of similarphyla (plural for phylum). Try this memory tool tohelp you remember the order of the groups fromkingdom to species: keep putting chocolate out forgoodness sake.
The first letter of each word standsfor one of the taxa.Look at the figure to the left again. The raccoonand guinea pig share only the groups with the broadest characteristics. They are both part of the kingdomAnimalia, the phylum Chordata, and the class Mammalia. But the similarities between the raccoon andguinea pig end at that point because the raccoonand guinea pig are really not very similar.Are there other ways to classify plantsand animals?We will use the six-kingdom classification system.However, there are several other classification systems.
For example, some taxonomists use the sixkingdom system but add a taxon called domains. Thedomain includes all six kingdoms.186Chapter 17READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.4. Which taxonomic groupis a group of similarfamilies?A classification system makes it easier to find things. For example, one of the ways the books in a library are classified is by fiction and nonfiction. The fiction books might then be divided intoadult, youth, and children’s books to make it easy for readers tofind just the right book.Living organisms are divided by groups called taxa (singular,taxon). The taxa range from having very broad characteristics tomuch more specific characteristics.
The smallest taxon is species.At the species level, organisms look alike and are able to breedwith one another. The next largest taxon is genus. At the genuslevel, there is a group of similar species that are closely related.NameDateClassSection17.1Classification, continued◗ After You ReadMini Glossarybinomial nomenclature: two-word system developed by Carolus Linnaeus to name species;first word identifies the genus of the organism, the second word is the specific epithetand often describes a characteristic of theorganismgenus: first word of a two-part scientific nameused to identify a group of similar speciesclass: taxonomic grouping of similar ordersclassification: grouping of objects or information based on similaritiesspecific epithet: the second word of a speciesname, which often describes a characteristicof an organismdivision: taxonomic grouping of similar classes;term used instead of phyla by planttaxonomiststaxonomy: branch of biology that groups andnames organisms based on studies of theirshared characteristicskingdom: taxonomic grouping of similar phylaorder: taxonomic grouping of similar familiesphylum: taxonomic grouping of similar classesfamily: taxonomic grouping of similar genera1.
Read the terms and their definitions in the Mini Glossary above. Find two terms in the MiniGlossary that make up the two-word naming system called binomial nomenclature. Writethe terms on the lines provided.____________________________________________________________________________________Copyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.____________________________________________________________________________________2. Fill in the lines of the triangle to show the taxonomic classification system.KingdomSpeciesVisit the Glencoe Science Web site at science.glencoe.com to findyour biology book and learn more about classification.READING ESSENTIALSChapter 17187NameDateClassSection17.2 The Six KingdomsSC.D.1.4.3 The student knows that changes in Earth’s climate, geological activity, and life forms may be traced and compared. SC.G.1.4.1 The student knows of the great diversity and interdependence of living things.
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