Section 1: The Linnaean System of Classification 17.1 Reading Guide KEY CONCEPT Organisms can be classified based on physical similarities. VOCABULARY taxonomy taxon binomial nomenclature genus MAIN IDEA: Linnaeus developed the scientific naming system still used today. Fill in the Concept Map with details about Linnaean taxonomy. Linnaean taxonomy classifies names 1. groups of 4. parts based on using a system called 2. physical 5. binomial into groups called which gives each species a 3. 6. scientific Holt McDougal Biology 0 The Tree of Life Section 1: The Linnaean System of Classification
17.1 Reading Guide continued MAIN IDEA: Linnaeus classification system has seven levels. Choose the best answer to the question or statement. 7. How are the seven levels of Linnaeus classification system organized? a. based on their physical similarities b. based on their physical differences c. based on their ability to be domesticated d. based on their ability to evolve 8. Describe the trend in the levels, or taxa, as you move down from kingdom to species. a. The levels move from more specific to more general. b. The levels move from more general to more specific. c. The levels are in order based on how long a species has lived on Earth. d. The levels are organized according to where a species gets food, drink, and air. Fill in the seven taxa of the Linnaean classification system into the appropriate boxes below. The first and last items are done for you. a. kingdom b. c. d. e. f. g. species Holt McDougal Biology 1 The Tree of Life Section 1: The Linnaean System of Classification
17.1 Reading Guide continued MAIN IDEA: The Linnaean classification system has limitations. Choose whether the statement is true or false. 9. true / false When Linnaeus set up his classification system, it was not yet possible for scientists to do molecular or genetic research. 10. true / false Linnaeus classification system contains no mistakes. 11. true / false Today, scientists use genetic similarities between species to help classify them as related species, rather than focusing on physical or structural similarities. Vocabulary Check Match each word or phrase with its definition. 12. taxonomy a. the science of naming and classifying organisms 13. binomial nomenclature b. one or more physically similar species thought to be closely related 14. taxon c. a system that gives each species a two-part Latin name 15. genus d. a group of organisms in a classification system Holt McDougal Biology 2 The Tree of Life Section 1: The Linnaean System of Classification
Section 2: Classification Based on Evolutionary Relationships 17.2 Reading Guide KEY CONCEPT Modern classification is based on evolutionary relationships. VOCABULARY phylogeny cladistics cladogram derived character MAIN IDEA: Cladistics is classification based on common ancestry. Choose the best answer for the question. 1. What is a phylogeny? a. similar traits that evolve in dissimilar species b. environmental conditions that cause traits to develop c. a classification based on common ancestry d. the evolutionary history for a group of species 2. How can a phylogeny be shown? a. as a branching tree diagram b. as a Venn diagram c. as a mind map d. as a bar graph or chart 3. What is the main goal of cladistics? a. to show how members of different families are related b. to show how members of different species are related c. to show how members of different genera are related d. to show how members of different kingdoms are related Holt McDougal Biology 3 The Tree of Life Section 2: Classification Based on Evolutionary Relationships
17.2 Reading Guide continued Use the word box below, and refer to Figure 2.2, to label the main features of a cladogram. The first one is done for you. clade node taxon being classified derived character 5. 4. taxon being classified 6. 7. Choose the best answer for the question. 8. What letter does a clade look like on a cladogram? a. the letter W b. the letter N c. the letter V d. the letter K 9. What do the hash marks for the derived characters in a cladogram indicate? a. that organisms below that hash mark all share that characteristic b. that none of the organisms below the hash mark share that characteristic c. that all of the organisms above and below the hash mark share that characteristic d. that none of the organisms anywhere on the cladogram have that characteristic 10. On a cladogram, what is a node? a. a part of the cladogram that is shaped like a letter of the alphabet b. a place where a branch splits off from the rest of the cladogram c. the topmost section of the cladogram d. the lowermost section of the cladogram Holt McDougal Biology 4 The Tree of Life Section 2: Classification Based on Evolutionary Relationships
17.2 Reading Guide continued MAIN IDEA: Molecular evidence reveals species relatedness. Choose whether the statement is true or false. 11. true / false Molecular data always agree with the classification of species based on physical similarities. 12. true / false Once an evolutionary tree is established, it can never be changed. 13. true / false DNA evidence can help scientists to learn how two species are related to each other. 14. true / false The more similar the genes of two species are, the more closely related the species are likely to be. Vocabulary Check Choose the word or phrase that best completes the statement. 15. Phylo- comes from the Greek word meaning class, and the suffix -geny means origin. From this, it is possible to see that phylogeny refers to a species evolutionary history / molecular makeup. 16. The words cladistics and cladogram are both related to the word clade / climb. 17. Traits that are shared by some species of a group being studied, which other species in that group do not have, are called identifying / derived characters. 18. Sketch a blank cladogram in the space below and label its parts. Holt McDougal Biology 5 The Tree of Life Section 2: Classification Based on Evolutionary Relationships
Section 3: Molecular Clocks 17.3 Reading Guide KEY CONCEPT Molecular clocks provide clues to evolutionary history. VOCABULARY molecular clock mitochondrial DNA ribosomal RNA MAIN IDEA: Molecular clocks use mutations to estimate evolutionary time. Choose the best answer for the question. 1. What is the ticking in a molecular clock? a. It is the same as the ticking in an ordinary clock. b. It is the same as the decay of radioactive isotopes used in radiometric dating. c. It is the rate at which a group of related species tends to mutate. d. It is the rate at which one organism of one species tends to mutate. 2. How can scientists link molecular data with real time? a. They can use radiometric dating. b. They can use relative dating. c. They can use the timing of a geologic event known to have separated species. d. They can use the date of collection of the specimen from which they obtained data. 3. How can fossil evidence help scientists with molecular dating? a. Scientists can use the date of the first appearance of an organism in the fossil record. b. Scientists can compare fossils with each other to see whether they are different. c. Scientists can determine the date from the rate of decay of molecules in the fossils. d. Scientists can assume that similar looking fossils are from the same period. Holt McDougal Biology 6 The Tree of Life Section 3: Molecular Clocks
17.3 Reading Guide continued 4. Using Figure 3.1 as a reference, draw your own set of DNA sequences that illustrate molecular evolution. DNA Sequence from a hypothetical ancestor Ten million years later One mutation in each lineage Another ten million years later One more mutation in each lineage MAIN IDEA: Mitochondrial DNA and ribosomal RNA provide two types of molecular clocks. 5. Fill in the spaces and blanks in the table below about two commonly used molecular clocks. Molecular Clock Organelle of Cell Rate of Mutations Why It s Useful as a Molecular Clock mtdna About ten times faster than nuclear DNA Passed down through the, not through both parents, so it remains unshuffled during reproduction rrna ribosomes Useful for studying distantly related in a different kingdom or phyla Vocabulary Check In each blank, write the term that matches the definition. molecular clock mitochondrial DNA ribosomal RNA 6. Useful for studying closely related species 7. Model that uses mutation rates to measure evolutionary time 8. Useful for studying species in different kingdoms or phyla Holt McDougal Biology 7 The Tree of Life Section 3: Molecular Clocks
Section 4: Domains and Kingdoms 17.4 Reading Guide KEY CONCEPT The current tree of life has three domains. VOCABULARY Bacteria Archaea Eukarya MAIN IDEA: Classification is always a work in progress. Choose the best answer to the question. 1. Why is classification considered a work in progress? a. Because it contains no mistakes. b. Because it is not very accurate. c. Because it must be corrected when new knowledge becomes available. d. Because it cannot be changed once it has been published in a book. 2. How has the kingdom system changed over the last three hundred years? a. There is one more kingdom than there was 300 years ago. b. There are two more kingdoms than there were 300 years ago. c. There are three more kingdoms than there were 300 years ago. d. There are four more kingdoms than there were 300 years ago. 3. Describe Woese s discovery and the impact it had on the tree of life. a. He discovered that bacteria and archaea are genetically different kingdoms. b. He discovered that bacteria and archaea should be combined into one kingdom. c. He discovered that bacteria are genetically related to fungi. d. He discovered that molds and mushrooms are genetically a type of bacteria. Holt McDougal Biology 8 The Tree of Life Section 4: Domains and Kingdoms
17.4 Reading Guide continued On the timeline below, write the kingdoms that existed at each point in time. 1753: 1938: 1977: 1700 1800 1900 2000 1866: 1959: 2000 MAIN IDEA: The three domains in the tree of life are Bacteria, Archaea, and Eukarya. Fill in blanks in the table below with notes about the three-domain system. Domain Characteristics Kingdoms Included 4. Bacteria One of the groups of organisms on Earth Single-celled prokaryotes in the kingdom 5. Archaea Different from bacteria Known for their ability to survive in environments Also single-celled prokaryotes, but from the kingdom 6. Eukarya Organisms that have cells containing a distinct Organelles within eukaryotic cells are surrounded by Can be colonial or All organisms with cells. Includes the kingdoms of, Plantae,, and Animalia. Holt McDougal Biology 9 The Tree of Life Section 4: Domains and Kingdoms