Reading Essentials for Biology Glencoe (794133), страница 45
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Also covers SC.D.1.4.4◗ Before You ReadThis section is about the six kingdoms into which all living things are classified. Things are classifiedaccording to characteristics. Take a look at a family. What tells you these people are related? Is theirhair the same color? Do they speak the same way? On the lines below, make a list of characteristicsyou would use to identify members of the same family.______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________◗ Read to LearnIdentify MainIdeas Highlight the mainidea in each paragraph.1.
What are the five characteristics used to determineevolutionary relationships?________________________________________________________________________________________________________________________188Chapter 17Evolutionary relationships are determined based on similarities in structure, breeding behavior, geographical distribution,chromosomes, and biochemistry. These characteristics giveclues about how species evolved. They also show probable evolutionary relationships.Structural similarities are the physical features that species havein common. When species have many physical features that arevery similar, there is reason to believe that they may have evolvedfrom a common ancestor.
This is the case for bobcats and lynxes.They have so many structural similarities that taxonomists suggestthey evolved from a common ancestor.Breeding behavior is another characteristic used to determineevolutionary relationships. For example, in one pond area therewere frogs thought to be of the same species. During the breeding season, however, the male frogs in each group made very different sounds to attract females of their own group.
This helpeddetermine that the frogs were actually two different species.A species’ geographical distribution (where a species lives)can help biologists determine its relationship with other species.For example, there are many different species of birds called fincheson the Galápagos Islands off the west coast of South America.Biologists suggest that in the past there was only one species offinch on the islands.
The finches probably moved to differentparts of the islands and evolved into distinct species over time.READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.How are evolutionary relationshipsdetermined?NameDateClassSection17.2The Six Kingdoms, continuedAnother characteristic scientists use to determine evolutionaryrelationships is chromosome similarity. Many species do not lookalike, but they do have similar chromosomes. When this is true,scientists believe the species are related.
For example, even thoughthe plants broccoli, kale, cabbage, and cauliflower do not look alike,they do have chromosomes that are almost identical in structure.Biochemistry also is used to determine evolutionary relationships. Scientists study the DNA of species and find that closelyrelated species have similar DNA sequences and, therefore, similar proteins. Sometimes these biochemical studies reveal thatspecies once thought to be closely related are not. This is the casewith the red panda and the giant panda.
The red panda is actuallymore closely related to raccoons. The giant panda is more closelyrelated to bears. Biochemical studies of the pandas show them notto be closely related to each other.Copyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Phylogenetic Classification: ModelsThe evolutionary history of a species is called its phylogeny(fy LAH juh nee). There are different models that show the phylogeny of a species.One system of classification based on phylogeny is cladistics(kla DIHS tiks).
Scientists who use cladistics assume that asgroups of organisms evolve from a common ancestor, they keepsome unique inherited characteristics. Taxonomists call theseunique inherited characteristics derived traits. Biologists use thesederived traits to make a branching diagram called a cladogram(KLA deh gram).VelociraptorAllosaurus2. Analyze Finding thattwo species have similarDNA is an example ofstudying which characteristic to determine evolutionary relationships?(Circle your choice.)a. biochemistryb. geographicaldistributionc. structural similaritiesRobinArchaeopteryxSinornisTheropodsLight bonesREADING ESSENTIALS3-toed footwishboneDownfeathersFeathers withshaft, veins,and barbsFlight feathers;arms as longas legsChapter 17189NameDateClassSectionThe Six Kingdoms, continued3.
Conclude Using the figure below, decide whichspecies are most closelyrelated. (Circle yourchoice.)a. mammals and sea starsb. ferns and conifersc. sponges andarthropodsd. flowering plants andbirdsAn example of a cladogram appears on page 189. It showsthe possible ancestry of modern birds, such as the robin. Noticethe derived traits listed across the bottom of the diagram. Themore derived traits organisms share, the more closely related theyare thought to be. The closer two organisms are on a cladogram,the more likely it is that they share a recent common ancestor. Sothe Archaeopteryx and the robin are thought to be more closelyrelated than the Velociraptor and the robin. Remember, though,that cladograms show only probable evolutionary relationships;they are not definite relationships.Another model scientists use to show the phylogeny of a speciesis fan shaped. Unlike the cladogram, the fanlike diagram may showthe time organisms became extinct. It may also show the numberof species in a group.
The fanlike diagram uses information fromfossils and structural, biochemical, and cladistic studies. An example is shown below. It shows the six-kingdom classification system. In this model, species that are closer together are probablymore closely related.MammalsReptilesand birdsAmphibiansand fishesFloweringPlantsSea StarsConifersFernsPlantsAnimalsArthropodsMossesMollusksand wormsFungiProtistsArchaebacteriaEubacteria190Chapter 17Jellyfishesand spongesREADING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.17.2NameDateClassSection17.2The Six Kingdoms, continuedCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.The Six Kingdoms of OrganismsAs you can see in the figure on page 190, the six kingdoms oforganisms are archaebacteria, eubacteria, protists, fungi, plants,and animals. There are two main characteristics that separate thesix kingdoms.
Those characteristics are cell structure and the wayin which the organisms get energy.Eubacteria (yew bak TEER ee uh) have strong cell walls. Someeubacteria eat other organisms for energy; they are heterotrophs.Other eubacteria make their own energy; they are autotrophs.Some eubacteria make their own energy the way plants do; theyare photosynthetic.
Others make energy by chemical reactions;they are chemosynthetic. The eubacteria live in most habitats,except the most extreme. Some eubacteria cause diseases, likestrep throat and pneumonia. Most eubacteria, however, are notharmful and many are helpful.Archaebacteria (ar kee bac TEER ee uh) have very different cellwalls than eubacteria. But like eubacteria, archaebacteria maketheir own energy.
They are chemosynthetic and photosynthetic.Archaebacteria live in extreme environments. They live in suchplaces as swamps, deep-ocean hot-water vents and seawater evaporating ponds. The environments in which the archaebacteria liveoften have no oxygen.Protists have simple organ systems. They live in moist environments. Protists can be unicellular, and have one cell or bemulticellular, and have many cells. Some protists are autotrophs,similar to plants. Others are heterotrophs, similar to animals. Stillothers are funguslike heterotrophs that produce reproductivestructures like fungi.Fungi (singular, fungus) can be either unicellular or multicellular.
Fungi are stationary; they do not move from one place toanother. Fungi are heterotrophs; they do not make their ownenergy. Instead, they absorb nutrients from organic materials intheir environment.Plants are multicellular. Their cells have walls. They do notmove from place to place; they are stationary. Plants are autotrophs; they make their own energy by the photosynthesis process.Photosynthesis also provides oxygen in the atmosphere.
There areover 250 000 species of plants. These include flowering plants,mosses, ferns, and evergreens.READING ESSENTIALS4. List two ways fungi andplants are different.________________________________________________Chapter 17191NameDateClassSection17.2The Six Kingdoms, continuedAnimals are also multicellular. But their cells do not have walls.Animals’ cells are organized into tissues, tissues are organized intoorgans, and organs are organized into organ systems. Most animalsare able to move from place to place. Animals are heterotrophs;they eat other organisms for energy.◗ After You ReadMini Glossarycladistics: biological classification system based onphylogeny; assumes that as groups of organisms diverge and evolve from a commonancestral group, they retain derived traitsfungus: group of unicellular or multicellular heterotrophic eukaryotes that do not movefrom place to place; absorb nutrients fromorganic materials in the environmentcladogram: branching diagram that models thephylogeny of a species based on the derivedtraits of a group of organismsphylogeny (fy LAH juh nee): evolutionary historyof a species based on comparative relationships of structures and comparisons of modern life forms with fossilsprotist: diverse group of multicellular or unicellular eukaryotes that lack complex organsystems and live in moist environments; maybe autotrophic or heterotrophic1.
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