Name Class Date 18 Classification Changing Ideas About Kingdoms As biologists learned more about the natural world, they realized that Linnaeus s two kingdoms, Animalia and Plantae, did not represent all life. Researchers found that microorganisms were very different from plants and animals. They were placed in their own kingdom, called Protista. Then, yeast, molds, and mushrooms were separated from plants and placed in their own kingdom, called Fungi. Because bacteria lack nuclei, mitochondria, and chloroplasts, they were separated from Protista and placed in another new kingdom, called Monera. In the 1990s, kingdom Monera was divided into two kingdoms: Eubacteria and Archaebacteria. The six-kingdom system of classification includes the kingdoms Eubacteria, Archaebacteria, Protista, Fungi, Plantae, and Animalia. Genetic analysis revealed that two prokaryotic groups are even more different from each other, and from Eukaryotes, than previously thought. This discovery lead to the creation of a new taxon, called the domain. The domain is a larger, more inclusive category than a kingdom. The three domain system consists of: Bacteria, Archaea, and Eukarya. Domain Bacteria corresponds to the kingdom Eubacteria. Domain Archaea corresponds to the kingdom Archaebacteria. Domain Eukarya corresponds tokingdoms Fungi, Plantae, Animalia, and Protista. Quotations are used for the old kingdom Protista to signify that it is not a valid clade. The Tree of All Life The tree of life shows current hypotheses regarding evolutionary relationships among taxa within the three domains of life. The domain Bacteria includes unicellular organisms without a nucleus. They have cell walls containing a substance called peptidoglycan. The domain Archaea also includes unicellular organisms without a nucleus. These organisms have cell walls that do not contain peptidoglycan. The domain Eukarya includes the four remaining kingdoms: Protista, Fungi, Plantae, and Animalia. All members of the domain Eukarya have cells with a nucleus. Most members of the kingdom Protista, are unicellular organisms. Some Protista are photosynthetic; others are heterotrophs. Most members of the kingdom Fungi are multicellular, and all members of this kingdom are heterotrophs with cell walls containing chitin. All members of the kingdom Plantae are multicellular and photosynthetic. Most plants cannot move about, and their cells have cell walls. All members of the kingdom Animalia are multicellular heterotrophs. Most animals can move about, and their cells lack cell walls.
BUILD Vocabulary A. The chart below shows key terms from the lesson with their definitions. Complete the chart by writing a strategy to help you remember the meaning of each term. One has been done for you. Term Definition The two-word naming system in which each organism is given a genus name and species name A group of similar orders A group of similar genera A group of similar species The largest and most inclusive group in the Linnaean classification system A group of similar classes BUILD Connections Levels in Your Life The pyramid below is similar to a pyramid used to show the Linnaean classification system. 1. Think about the different levels of organization in your life from you as an individual to you as a resident of the world. 2. Fill in the rest of the pyramid with other taxa. Me The world Answer the question.
3. How are the levels in your pyramid similar to the different levels of the Linnaean classification system? Linnaean Classification System Linnaeus developed a system of classification to name and group organisms in a logical manner. This made it easier to study the many forms of life. In Linnaeus s system, there are seven levels: kingdom, phylum, class, order, family, genus, species. Look at the first letter in each word of the sentence Kids prefer candy over fresh green spinach. This will help you to remember the names of the seven levels in the correct order. The diagram at the right shows how a grizzly bear is classified in the Linnaean classification system. 1. Fill in the names of the taxa. Use the words from the box. kingdom class species phylum 2. Put an X on the highest, or most specific, taxon that includes the grizzly bear and the red fox. 3. Circle the taxa that include reptiles. Answer the questions. order genus family 4. Using binomial nomenclature, what is the scientific name of the grizzly bear? Species Ursus arctos Ursus Ursidae 5. To which phylum does the grizzly bear belong? 6. Name one other animal that belongs to the same class as the grizzly bear. Carnivora 7. What type of animals belong to the same family as Ursus arctos? Mammalia Chordata Animalia
Cladograms Reading Cladograms A cladogram shows evolutionary relationships between species. 1. Use blue to color the organisms that have a molted external skeleton. 2. Use red to color the organisms without a molted external skeleton. 3. Circle the point on the cladogram that shows the most recent common ancestor of the crab and the barnacle. 4. Draw an X at the point on the cladogram that shows the most recent common ancestor of mollusks and crustaceans. Crustaceans CLADOGRAM Mollusk Crab Barnacle Limpet Molted external skeleton Segmentation Tiny free-swimming larva Answer the questions. Circle the correct answers. 5. Which organism, or organisms, shows segmentation? barnacle limpet 6. What do all three organisms have in common? tiny free-swimming larva molted external skeleton segmentation
Chapter Review Use the clues and words to help you write the vocabulary terms from the chapter in the blanks. phylum kingdom cladogram 1. is the largest taxon in the Linnaean classification system. 2. is used to show how different species are related to a common ancestor. 3. is made up of similar classes. Answer the following questions. 4. Binomial nomenclature was developed by. 5. In binomial nomenclature, part of an organism s scientific name is A. the name of its phylum. C. the name of its family. B. the name of its order. D. the name of its genus. 6. Draw and label a pyramid to show the order of the different classification groups. Use these words: species, domain, phylum, order, class, kingdom, family, genus. 7. According to the cladogram below, which two clades include animals that have specialized shearing teeth? Clade Tetrapoda Clade Amniota Clade Mammalia Clade Carnivora Clade Felidae Amphibians Reptiles Marsupials Dogs and relatives Cats Four limbs Amniotic egg (egg with membranes) Hair Specialized shearing teeth Retractable claws