Phylogenetics Flashcards
What is systematics?
The classification of organisms and the determination of their evolutionary relationships.
What is phylogeny?
The evolutionary history of a species or a group of related species.
What is taxonomy?
The ordered division and naming of organisms.
What are the two key features of binomial nomenclature?
- The genus
- Unique for each species within the genus.
Ex. Homo sapiens
List the taxonomic groups fro, broad to narrow.
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What does a branch point on a phylogenetic tree represent?
The divergence of two species.
What are sister taxa?
Groups that share an immediate common ancestor.
What can we or cant’t we learn from a phylogenetic tree?
- Show patterns of descent, not phenotypic similarity.
- Do not indicate when species evolved or how much change occurred in a lineage.
- It should not be assumed that a taxon evolved from the taxon next to it.
Why is differentiating between homology and analogy important when constructing a tree?
So you can distinguish whether similarity is due to shared ancestry (homology) or convergent evolution (analogy).
What is molecular systematics?
The use of DNA and other molecular data to determine evolutionary relationships.
What is cladistics?
Groups organisms by common descent.
What is a monophyletic clade?
A grouping that consists of the ancestor species and all its descendants.
What is a paraphyletic clade?
Grouping that consists of the ancestral species and some, but not all, of its descendants.
What is a polyphyletic clade?
A grouping that consists of various species with different ancestors.
What is a clade?
A group of species that includes an ancestral species and all its descendants.
What is the difference between a shared ancestral character and a shared derived character?
A shared ancestral character is a character that originated In an ancestor of the taxon. A shared derived character is an evolutionary novelty unique to a particular clade.
What is an outgroup? An ingroup?
An outgroup is a group that has diverged before the ingroup. The ingroup is compared to the outgroup to differentiate between shared derived and ancestral characteristics.
How are the outgroup and ingroup species used to offer a phylogenetic tree?
The ingroup species are compared to the outgroup to differentiate between shared derived and ancestral characteristics.
What can branch length indicate?
It can reflect the number of genetic changes that have taken place in that lineage. It can also represet chronological time.
What is the molecular clock?
A method for estimating the time required for a given amount of evolutionary change, based on the observation that some regions of genomes evolve at constant rates.
