Order From Chaos

1. Interest Grabber Section 18-1 Order From Chaos • When you need a new pair of shoes, what do you do? You probably walk confidently into a shoe store, past the tens or hundreds of pairs of shoes you don’t want and straight to the kind you do want. How do you find them? Shoes are organized in the store in categories. People organize objects by grouping similar objects together. Go to Section:

2. Interest Grabber continued Section 18-1 • 1. Consider the task facing early biologists who attempted to organize living things. How might they have begun? • 2. Suppose that you have been given a green plant, stringy brown seaweed, a rabbit, a mushroom, a worm, and a grasshopper. You’ve been asked to organize these things into categories that make sense. How would you do it? • 3. Decide on your categories and write each on a sheet of paper. Next to each category, write the defining characteristics of that category. Then, write in the organisms that fall into each category. Go to Section:

3. Section Outline Section 18-1 • 18–1 Finding Order in Diversity A. Why Classify? B. Assigning Scientific Names 1. Early Efforts at Naming Organisms 2. Binomial Nomenclature C. Linnaeus’s System of Classification Go to Section:

4. Flowchart Section 18-1 Linnaeus’s System of Classification Kingdom Phylum Class Order Family Genus Species Go to Section:

5. Figure 18-5 Classification of Ursus arctos Section 18-1 Coral snake Abert squirrel Sea star Grizzly bear Black bear Giant panda Red fox KINGDOM Animalia PHYLUM Chordata CLASS Mammalia ORDER Carnivora FAMILY Ursidae GENUS Ursus SPECIES Ursus arctos Go to Section:

6. Interest Grabber Section 18-2 One Big Family? • How can you determine if one organism is closely related to another? It may seem easy, but it isn’t, and looks are often deceiving. For example, roses and orchids are both flowering plants, but roses grow on bushes or vines and have thorns. Many orchids don’t even grow in soil—they can grow in trees! Rose and orchid blossoms look very different, and roses and orchids cannot produce hybrids, or offspring of crosses between parents with different traits. Go to Section:

7. Interest Grabber continued Section 18-2 • 1. Do you think roses and orchids are closely related? Explain your answer. • 2. Now, apply the same logic to dogs. Different breeds of dogs—such as a Labrador retriever and a collie—can breed and produce offspring. So what is the difference between the rose-orchid combination and the Lab-collie combination? • 3. What defines a species? Is appearance important? What other factors might be considered? Go to Section:

8. Section Outline Section 18-2 • 18–2 Modern Evolutionary Classification A. Problems With Traditional Classification B. Evolutionary Classification C. Classification Using Cladograms D. Similarities in DNA and RNA E. Molecular Clocks Go to Section:

9. Traditional Classification Versus Cladogram Section 18-2 Appendages Conical Shells Crustaceans Gastropod Crab Crab Limpet Limpet Barnacle Barnacle Molted exoskeleton Segmentation Tiny free-swimming larva TRADITIONAL CLASSIFICATION CLADOGRAM Go to Section:

10. Traditional Classification Versus Cladogram Section 18-2 Appendages Conical Shells Crustaceans Gastropod Crab Crab Limpet Limpet Barnacle Barnacle Molted exoskeleton Segmentation Tiny free-swimming larva TRADITIONAL CLASSIFICATION CLADOGRAM Go to Section:

11. Interest Grabber Section 18-3 My Way or the Highway • Categories that are used to organize an assortment of things should be valid. That is, they should be based on real information. However, categories should be useful, too. Suppose that you are taking a survey of traffic. You sit at the side of a busy intersection and record the vehicles you see in one hour. Go to Section:

12. Interest Grabber continued Section 18-3 • 1. What categories could you use to organize your count of vehicles? • 2. Look at your list of categories. Are all of them equally useful? • 3. Is there more than one valid and useful way to organize living things? Go to Section:

13. Section Outline Section 18-3 • 18–3 Kingdoms and Domains A. The Tree of Life Evolves B. The Three-Domain System C. Domain Bacteria D. Domain Archaea E. Domain Eukarya 1. Protista 2. Fungi 3. Plantae 4. Animalia Go to Section:

14. Eukaryotic cells Prokaryotic cells Kingdom Plantae Kingdom Protista Domain Bacteria Domain Archaea Kingdom Fungi Kingdom Animalia Kingdom Eubacteria Kingdom Archaebacteria Concept Map Section 18-3 Living Things are characterized by Important characteristics which place them in and differing Domain Eukarya Cell wall structures such as which is subdivided into which place them in which coincides with which coincides with Go to Section:

15. Figure 18-12 Key Characteristics of Kingdoms and Domains Section 18-3 Classification of Living Things DOMAIN KINGDOM CELL TYPE CELL STRUCTURES NUMBER OF CELLS MODE OF NUTRITION EXAMPLES Bacteria Eubacteria Prokaryote Cell walls with peptidoglycan Unicellular Autotroph or heterotroph Streptococcus, Escherichia coli Archaea Archaebacteria Prokaryote Cell walls without peptidoglycan Unicellular Autotroph or heterotroph Methanogens, halophiles Protista Eukaryote Cell walls of cellulose in some; some have chloroplasts Most unicellular; some colonial; some multicellular Autotroph or heterotroph Amoeba, Paramecium, slime molds, giant kelp Fungi Eukaryote Cell walls of chitin Most multicellular; some unicellular Heterotroph Mushrooms, yeasts Eukarya Plantae Eukaryote Cell walls of cellulose; chloroplasts Multicellular Autotroph Mosses, ferns, flowering plants Animalia Eukaryote No cell walls or chloroplasts Multicellular Heterotroph Sponges, worms, insects, fishes, mammals Go to Section:

16. Figure 18-13 Cladogram of Six Kingdoms and Three Domains Section 18-3 DOMAIN ARCHAEA DOMAIN EUKARYA Kingdoms Eubacteria Archaebacteria Protista Plantae Fungi Animalia DOMAIN BACTERIA Go to Section: