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Questions and Answers
What does a branch point in a phylogenetic tree represent?
What does a branch point in a phylogenetic tree represent?
Which taxa diverged after the shared lineage split from taxon A?
Which taxa diverged after the shared lineage split from taxon A?
What could cause an organism to be reclassified in a phylogenetic context?
What could cause an organism to be reclassified in a phylogenetic context?
In the described diagram, what does branch point 3 represent?
In the described diagram, what does branch point 3 represent?
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Which genus is mentioned in the context?
Which genus is mentioned in the context?
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What does PhyloCode change about taxa classification?
What does PhyloCode change about taxa classification?
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What is a phylogenetic tree used to represent?
What is a phylogenetic tree used to represent?
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Which group would Aves be classified under based on evolutionary history?
Which group would Aves be classified under based on evolutionary history?
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What is one reason for misclassification of species by taxonomists?
What is one reason for misclassification of species by taxonomists?
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How are taxa currently classified according to traditional methods?
How are taxa currently classified according to traditional methods?
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What is a common misconception about the relationship between taxonomy and evolutionary history?
What is a common misconception about the relationship between taxonomy and evolutionary history?
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What approach are many systematists adopting due to PhyloCode?
What approach are many systematists adopting due to PhyloCode?
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Which of the following statements about evolutionary relationships is true?
Which of the following statements about evolutionary relationships is true?
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Which tree was identified as the most parsimonious among the three possible phylogenies?
Which tree was identified as the most parsimonious among the three possible phylogenies?
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How many additional base-change events do the trees at sites 2, 3, and 4 collectively require?
How many additional base-change events do the trees at sites 2, 3, and 4 collectively require?
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What is the total number of base-change events for Tree II?
What is the total number of base-change events for Tree II?
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What color were the hatchmarks indicating base-change events?
What color were the hatchmarks indicating base-change events?
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What identifies a phylogeny as most parsimonious?
What identifies a phylogeny as most parsimonious?
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How many events does Tree I require?
How many events does Tree I require?
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Which of the following is NOT a tree mentioned in the study?
Which of the following is NOT a tree mentioned in the study?
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What aspect is primarily considered when identifying the most parsimonious tree?
What aspect is primarily considered when identifying the most parsimonious tree?
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What does a phylogenetic tree illustrate regarding leopard, badger, and wolf?
What does a phylogenetic tree illustrate regarding leopard, badger, and wolf?
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What term describes evolution due to similar environmental pressures rather than shared ancestry?
What term describes evolution due to similar environmental pressures rather than shared ancestry?
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In constructing a phylogenetic tree, what is a potential error caused by confusion between analogy and homology?
In constructing a phylogenetic tree, what is a potential error caused by confusion between analogy and homology?
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If taxon E is the sister taxon to taxa D and F, what does this imply?
If taxon E is the sister taxon to taxa D and F, what does this imply?
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Which statement best describes analogy in the context of evolutionary biology?
Which statement best describes analogy in the context of evolutionary biology?
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What should scientists consider when estimating divergence times in phylogenetic trees?
What should scientists consider when estimating divergence times in phylogenetic trees?
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What is the significance of convergent evolution in studying phylogenetic relationships?
What is the significance of convergent evolution in studying phylogenetic relationships?
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Which evolutionary concept explains why two different species may display similar external traits?
Which evolutionary concept explains why two different species may display similar external traits?
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Why might hair not be a useful character for distinguishing a particular clade of mammals?
Why might hair not be a useful character for distinguishing a particular clade of mammals?
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What can gene duplication contribute to in the evolutionary process?
What can gene duplication contribute to in the evolutionary process?
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What is the primary concern with using the most parsimonious tree of evolutionary relationships?
What is the primary concern with using the most parsimonious tree of evolutionary relationships?
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Which type of gene is described as having divergence traced back to speciation events?
Which type of gene is described as having divergence traced back to speciation events?
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What is a significant aspect of molecular phylogenies concerning gene duplications?
What is a significant aspect of molecular phylogenies concerning gene duplications?
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How did traditional classifications view taxa besides birds and mammals?
How did traditional classifications view taxa besides birds and mammals?
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In the context of genome evolution, what is a major role of molecular systematics?
In the context of genome evolution, what is a major role of molecular systematics?
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What relationship do cytochrome c genes in humans and dogs illustrate?
What relationship do cytochrome c genes in humans and dogs illustrate?
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What type of genes are formed as a result of speciation?
What type of genes are formed as a result of speciation?
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Which genomic type is suggested to evolve relatively rapidly for tracking evolutionary relationships?
Which genomic type is suggested to evolve relatively rapidly for tracking evolutionary relationships?
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What percentage of genes are shared as orthologous between humans and mice?
What percentage of genes are shared as orthologous between humans and mice?
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Which organisms share 50% of their genes as orthologous despite 1 billion years of divergence?
Which organisms share 50% of their genes as orthologous despite 1 billion years of divergence?
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What does the comparison of rRNA sequences indicate about the evolutionary relationship of fungi?
What does the comparison of rRNA sequences indicate about the evolutionary relationship of fungi?
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What is one outcome of the divergence of lineages that occurred a long time ago?
What is one outcome of the divergence of lineages that occurred a long time ago?
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What role do biochemical and developmental pathways play in different organisms?
What role do biochemical and developmental pathways play in different organisms?
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What does the presence of orthologous genes between vastly different species suggest?
What does the presence of orthologous genes between vastly different species suggest?
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Study Notes
Phylogeny and the Tree of Life
- Biologists use evolutionary relationships to categorize species
- Comparing traits helps place species in the correct "container"
- Shared traits suggest close evolutionary relationships
- Legless condition evolved independently in different lizard groups
- Snakes and lizards are part of the evolutionary continuum
- Phylogeny traces the evolutionary history
- Observing phylogeny is about understanding evolutionary patterns.
Phylogenies Show Evolutionary Relationships
- Organisms share traits due to common ancestry
- Knowing a species' evolutionary history gives insight into its characteristics
- Shared genes, metabolic pathways, and structural proteins point to close relatives
- Taxonomy is the scientific discipline that names and classifies organisms
- Taxon is the named taxonomic unit at a specific hierarchical level.
Binomial Nomenclature
- Common names can cause confusion, as one name can refer to multiple species
- Scientific names (binomials) avoid such ambiguity.
- Binomials consist of the genus name (capitalized) and the species epithet (not capitalized)
- Scientific names are italicized
- Use of binomial names helps avoid ambiguity across languages and contexts.
Hierarchical Classification
- Species are grouped into increasingly inclusive categories.
- Species grouped into genera, genera into families, families into orders, orders into classes, classes into phyla, phyla into kingdoms, and kingdoms into domains.
- This resembles a postal address (e.g., individual apartment, to building, to street, to city).
- This system is called the Linnaean system.
- Taxa are the named taxonomic units at each level of the hierarchy.
Linking Classification and Phylogeny
- Phylogenetic trees depict evolutionary history as a branching diagram
- Branching patterns of phylogenetic trees often match how taxonomists classify organisms.
- Sometimes, species might be classified in a way that contradicts its true evolutionary history
- Loss of a key feature or other similar factors.
Shared Characters in Constructing Phylogenetic Trees
- Homologous characters reflect shared ancestry.
- Analogous characters result from convergent evolution.
- Using homologous characters is key to establish evolutionary relationships
- Phylogenetic trees are hypotheses about evolutionary relationships
- Outgroup is a species or group of species that branched from the lineage before the group being studied.
- Using outgroups can help establish evolutionary relationships among the species in the group.
Phylogenies Inferred from Morphological and Molecular Data
- Systematists collect and analyze information about organism's morphology, genes, and biochemistry
- to determine evolutionary relationships
- Homologous traits reflect shared ancestry.
- Distinguish homology from analogy (convergent evolution).
Molecular Homologies
- Comparing DNA sequences helps analyze evolutionary relationships in the absence of a strong fossil record.
- DNA sequences in closely related species differ in only one or a few sites.
- DNA sequences in distantly related species differ at numerous locations.
Evaluating Molecular Homologies
- Aligning comparable DNA sequences is the first step to comparing them.
- A computer program can determine the best way to align comparable DNA sequences.
Molecular Clocks and Evolutionary Time
- Molecular clocks measure average rates of change in genes or proteins.
- Gene or protein sequences can serve as reliable molecular clocks.
- Calculating the amount of difference in gene or protein sequences can help estimate the dates of events that cannot be determined from the fossil record
New Information Revises Understanding of the Tree of Life
- The current tree of life is based on three domains: Bacteria, Archaea, and Eukarya.
- Organisms are classified into domains based on ribosomal RNA gene sequences and other factors.
- Horizontal gene transfer makes understanding the tree of life complex.
- Gene transfer between organisms makes analyzing relationships more challenging.
Phylogenetic Trees as Hypotheses
- Any phylogenetic tree represents a hypothesis about the relationship amongst the species in the tree.
- The best hypothesis is the one that best fits all available data
- These hypotheses can be modified as new evidence becomes available.
- Can predict new characteristics based on phylogenetic bracketing.
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Description
Test your understanding of phylogeny and the tree of life. This quiz covers evolutionary relationships between species, shared traits, and the significance of taxonomy. Explore concepts like binomial nomenclature and how organisms are classified based on their evolutionary history.
