Understanding Phylogeny Flashcards
What is a population in the context of genetic exchange?
A population consists of multiple interbreeding individuals, which allows for the exchange of genes.
How is a species defined in terms of genetic exchange?
A species consists of multiple populations that occasionally exchange genes.
What is speciation and how does it occur?
Speciation is the process by which different species diverge from a common ancestor, leading to the development of new species.
What is phylogeny, and what does it represent?
Phylogeny is the genetic history of life, representing the history of genes, genomes, species, and broader lineages, often depicted as a branching tree.
What is a phylogenetic tree, and how is it used?
A phylogenetic tree is a branching diagram that depicts the genetic history of a set of organisms, often based on genetic data, showing evolutionary relationships.
What information can be derived from a phylogenetic tree?
A phylogenetic tree can show ancestral species, points of divergence into separate species, and relationships between species, including most recent common ancestors (MRCAs).
What are sister groups in a phylogenetic tree?
Sister groups are pairs of closest relatives that share the same most recent common ancestor (MRCA) and diverged at the same time.
What is the concept of “rotability of nodes” in phylogenetic trees?
The concept refers to the idea that the nodes in a phylogenetic tree can be rotated without changing the relationships between species, showing that species are not more “advanced” than others.
What is synapomorphy, and how is it used in phylogenetics?
Synapomorphy refers to a shared, derived trait that is used to identify monophyletic clades in a phylogenetic tree.
What is the principle of parsimony in reconstructing phylogenies?
Parsimony is the principle that the simplest tree, requiring the fewest evolutionary changes, is the most likely explanation for the observed data.
What is convergent evolution, and how does it affect phylogenetic analysis?
Convergent evolution occurs when unrelated species develop similar traits independently, often due to environmental pressures, making it difficult to determine true evolutionary relationships.
What role do statistical models play in reconstructing phylogenies?
Statistical models calculate the likelihood that observed nucleotide patterns would evolve under a given phylogenetic tree, helping to assess which tree best fits the data.
What is bootstrapping, and how is it used in assessing phylogenetic confidence?
Bootstrapping is a method of randomly resampling data to create multiple phylogenetic trees, allowing researchers to assess the confidence in clade groupings based on how consistently the trees match.
How can outgroups be used in phylogenetic trees?
Outgroups, which are closely related but not part of the group being studied, help root the tree and infer the ancestral state of the ingroup.
How do derived traits help in understanding evolutionary relationships?
Derived traits are changes from the ancestral condition that reflect common ancestry, and identifying these traits helps trace evolutionary lineages and relationships between species.
