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40 Cards in this Set
- Front
- Back
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what is the reconstruction and study of evolutionary relationships
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systematics
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an evolutionary tree that represents a hypothesis about patterns of relationship among species
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phylogeny
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phylogenies have what 3 key features
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time
origin relationships |
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similarity among species that is inherited from the most recent common ancestor of an entire group
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derived
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similarity that arose prior to the common ancestor of the group
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ancestral
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the distinguishment between ancestral and derived characteristics
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cladistics
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in cladistics what is the only thing considered
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shared derived characters
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how does the cladistic method require that character variation be identified?
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ancestral or derived
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the presence of hair is what type of feature of mammals
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shared derived feature
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the presence of lungs in mammals is what type of feature
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ancestral because its also present in amphibians and reptiles
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there is a number of morphological and DNA characters exist that are derived and shared between humans and chimps but not by gorillas or other great apes what does this suggest
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the characters suggest that chimps and humans diverged from a common ancestor that existed more recently than the common ancestor of gorillas chimps, and humans
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what does it mean to polarize the characters in cladistic analysis
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to determine whether particular character states are ancestral or derived
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when the group under study exhibits multiple character states and one of those states is exhibited by the outgroup then the state is considered to be what and other states are considered to be waht
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ancestral, derived
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once all characters have been polarized systematists use this info to construct
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a cladogram
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what does a cladogram predict
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a hypothesis of evolutionary relationships
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species that share a common ancestor are said to belong to what
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a clade
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what is a synapomorphy of a clade
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a derived character shared by clade members
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ancestral states are also called
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plesiomorphies
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shared ancestral states are called
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symplesiomorphies
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what is homoplasy
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a shared character state that has not been inherited from a common ancestor exhibiting that character state
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what does the principle of parsimony favor
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the hypothesis that requires the fewest assumptions
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the phylogeny that require the _____ assumptions is the best hypothesis of phylogenetic relationships
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fewest
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what states tat the rate of evolution of a molecule is constant through time
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molecular clock
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how we lace species and higher groups--genus, family class, and so forth--into the taxonomic hierarchy
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classification
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what is a monophyletic group
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a group that includes the most recent common ancestor of the group and all of its descendants
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by definition a clade is a _________ group
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monophyletic
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what does a paraphyletic group include
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the most recent common ancestor of the group but not all of its descendants
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what does a polyphyletic group include
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does not include the most recent common ancestor of all members of the group
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what types of data are used for building phylogenies
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morphology, molecules (protein or DNA), behavior (physiology)
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what is a character
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traits that are observed in organisms (e.g. DNA arrangement in cell)
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what is a character state
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recognizeable forms of traits
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what does cladistic use in its studies
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synapomorphies (shared derived characters) not simliarity
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what do outgroups do
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determine ancestral and derived character variation
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when does homolapsy occur
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when traits are shared but arent inherited from a common ancestor
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what are the uses of phylogenies
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1. aid in systematics and classification
2. distinguish between competing hypotheses 3. explain species diversification 4. identify patterns of disease transmission |
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homologous features are derived from what
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the same ancestral source
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whats the difference between homologous and homoplastic features?
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homoplastic features arent derived from the same ancestral source
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the parental care in dinosaurs, crocodiles, and birds is considered
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homologous
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a greater number of species per clade
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species richness
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phylogenetics helps to explain what
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species diversification
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