23 Questions
What do systematists infer from molecular evidence?
Phylogeny
Why should DNA and amino acid sequences be more similar between species that have recently branched from a common ancestor?
Due to the reflection of common ancestry in homology
Why is molecular systematics valuable in assessing phylogenetic relationships?
It can evaluate relationships beyond what comparative anatomy offers
Which type of groups benefit the most from molecular systematics due to limited morphological divergence?
Closely related groups
What is the basis for most molecular systematics analysis?
Comparison of nucleotide sequences in DNA or RNA
How do systematists construct cladograms using DNA sequence analysis?
Branch points defined by mutations in DNA sequence
What makes it easier to define identity using molecular data compared to morphological data?
Molecular data are less subject to homoplasy
In a rooted tree, what does the root represent?
Hypothetical ancestors
What is the main difference between a rooted and an unrooted tree?
Directionality in terms of evolutionary time
What is the significance of the phosphate group, sugar, and nitrogenous base in nucleotide structure?
They hook nucleotides together in DNA formation
Why can long branch attraction occur in molecular data analysis?
As a result of errors from fast mutation rates and limited characters
Which type of tree allows us to define ancestor-descendant relationships between nodes?
Rooted tree
What do terminal nodes represent in a tree?
Operational taxonomic units
What regions of DNA evolve relatively rapidly and are useful for assessing closely related species or populations?
mtDNA regions
In terms of evolutionary relationships, what does an unrooted tree lack compared to a rooted tree?
Specification of ancestors and descendants
Why do insertions and deletions in DNA sequences create challenges when establishing homology?
They introduce base changes that are difficult to align
How do two closely related species primarily differ in their DNA sequences?
By differing in multiple bases and having insertions or deletions
What is the core principle of Maximum Parsimony?
Minimizes evolutionary changes
Which method is statistically robust and incorporates evolutionary models?
Maximum Likelihood (ML)
What is a disadvantage of using Unweighted Pair-Group Method with Arithmetic Mean (UPGMA)?
Not statistically rigorous
When applying parsimony to a problem in molecular systematics, which dataset size is more suitable for Maximum Parsimony according to the text?
Smaller datasets, qualitative analysis, exploration, uncertain model assumptions
What does Neighbor Joining (NJ) primarily do in constructing phylogenetic trees?
Iteratively joins closest sequences, updates distances
In the context of Maximum Likelihood (ML), what does 'maximizes probability of observed data under a model' mean?
Selects the tree with the highest likelihood score
Explore the principles and applications of molecular systematics in inferring phylogenetic relationships among species. Learn how genes and proteins are compared to trace evolutionary history and revise taxonomic trees based on molecular evidence.
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