Biology Ch. 26 – Flashcards
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The analytical approach to understanding the diversity and relatedness of both extant and extinct organisms is called _____.
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systematics
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What is the focus of the branch of biology called taxonomy?
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the classification of life-forms by their similarities and differences
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The binomial system assigns to each organism a unique name that describes its _____.
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genus and species
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The two-part format of the scientific name, referred to as binomial, ensures that _____.
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A) Each species is assigned a unique name
B) Systematists can easily specify the closest relatives of any species
C) Each species has a name that is understandable regardless of language barriers among scientists
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Which of the following is the correct taxonomic name for the African forest elephant?
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Loxodonta cyclotis
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A taxon _____.
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is a formal grouping at any given level
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Rabbits and guinea pigs both belong to Class Mammalia. This means they must also both belong to _____.
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phylum Chordata
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Species A and species B are in the same phylum. Species A and species C, but not species B, are in the same order. From this information you can conclude that _____.
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species C could be in the same class as species A and B
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What does a branch point in a phylogenetic tree represent?
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A branch point represents a point at which two evolutionary lineages split from a common ancestor.
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Which of the following methods to establish phylogenetic relationships among organisms has been developed most recently?
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comparing the component sequences of proteins and nucleic acids
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The wings of a hummingbird and a bee are _____.
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analogous
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Which of the following would be the least useful in determining the relationships among various species?
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analogous structures
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Researchers can use molecular homologies to _____.
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reveal the number of mutations in a particular sequence that has occurred in each species since they diverged from a common ancestor
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A phylogenetic tree of bird families constructed by cladistic analysis would be a hypothesis about which of the following?
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evolutionary relationships among bird families
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Looking at the table and phylogenetic tree in Figure 26.11, which of the following is a true statement?
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Four walking legs is a shared derived character in salamanders and a shared ancestral character in turtles.
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Many researchers who study the kingdom Protista argue that all of these organisms should not be placed in the same kingdom, because these organisms could not have evolved from a common ancestor. In other words, they argue that the kingdom Protista is _____.
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polyphyletic
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Using cladistic analysis, a taxonomist wishes to construct a phylogenetic tree showing the relationships among various species of mammals. Which of the following would be the least useful for this purpose?
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the fact that all mammals have hair
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Which statement below is true about an outgroup?
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The outgroup should be less closely related to any members of the ingroup than they are to each other.
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Unlike a regular phylogenetic tree, phylogenetic trees with branch lengths proportional to time can be used to _____.
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represent the chronological time that has passed since two groups diverged from a common ancestor
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Which statement below is true of parsimonious trees?
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The best tree requires the fewest evolutionary events to have occurred in the form of shared derived characters.
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Birds and mammals have a four-chambered heart, but most reptiles have a three-chambered heart. How does this fact affect the construction of phylogenetic trees for these groups?
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The most likely tree is not always the most parsimonious.
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If you wanted to determine the lineage of plants that have evolved on a relatively young archipelago—approximately 15,000 years old—what type of nucleic acid should you compare?
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mtDNA
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Paralogous genes _____.
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result from gene duplication
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What is the evolutionary significance of paralogous genes?
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They increase the size of the genome and provide more opportunity for the evolution of novel characteristics.
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What is the evolutionary significance of orthologous genes?
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The high percentage of orthologous genes found in vastly different organisms emphasizes the many biochemical and developmental pathways shared by all organisms.
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Which of the following best summarizes the neutral theory?
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Darwinian selection does not influence a lot of evolutionary change in genes and proteins because many of these changes do not affect fitness.
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The idea of using molecules as clocks to time evolutionary events is very attractive, but there are many problems in actually applying the technique. What seems to be the best way to get reliable results?
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Darwinian selection does not influence a lot of evolutionary change in genes and proteins because many of these changes do not affect fitness.
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By applying a molecular clock, researchers have proposed that the first HIV-1 M invasion into humans occurred in the _____.
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1930s
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To which domain is the domain Eukarya (the domain to which humans belong) most closely related?
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It is not clear whether eukaryotes are more closely related to bacteria or archaea.
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Universal phylogenetic trees built from different genes sometimes give inconsistent results. What basic assumption on which phylogenetic trees are based has probably been violated during the history of life?
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Genes are passed vertically from one generation to the next.
