Chapter 26 Flashcards
Phylogeny
the evolutionary history of a species or group of related species
Systematics
a discipline that deals with the classification of organisms and the determining of their evolutionary relationships
Taxonomy
the scientific discipline concerned with classifying and naming organisms
What two key features in Carolus Linnaeus’s system of taxonomy (based on resemblances) remain useful today
1) Two-part names for species
2) hierarchical classification
Binomial
The two-part scientific name of a species
The first part of a binomial is the _______ and the second part, which is unique for each species, is _______
genus; specific epithet
T/F: The specific epithet of a species can be sufficient to name a species
False; both parts together name the species
The eight parts of Hierarchical Classification
1) Domain
2) Kingdom
3) Phylum
4) Class
5) Order
6) Family
7) Genus
8) Species
Danny Kicked Puppies Carelessly Often For Gits and Shiggles
Taxon
A taxonomic unit at any level of hierarchy
Branch point
represents the divergence of two species
Sister taxa
groups that share an immediate common ancestor on a phylogeny
Rooted Tree
Includes a branch to represent the last common ancestor of all taxa in the tree
Basal taxon
diverges early in the history of a group and originates near the common ancestor of the group
Polytomy
A branch from which more than two groups emerge
Homology
similarity due to shared ancestry
Analogy
similarity due to convergent evolution
Aligning segments of DNA
If deletions or insertions occur, DNA will align itself
Cladistics
groups organisms by common descent
Clade
A group of species that includes an ancestral species and all its descendants
T/F: Clades can not be nested in larger clades
False; they can be
T/F: All groupings of organisms qualify as clades
False; not all groupings of organisms qualify as clades
A valid clade is __________, signifying that…
monophyletic; it consists of the ancestor species and all its descendants
Paraphyletic group
consists of an ancestral species and some, but not all, of the descendants
Polyphyletic grouping
includes distantly related species but does not include their most recent common ancestor
Shared ancestral character
a character that originated in an ancestor of the taxon
Shared derived character
an evolutionary novelty unique to a particular clade
T/F: A character can be both ancestral and derived, depending on the context
True
Outgroup
A species or group of species that is closely related to the in-group
Ingroup
the various species being studied
Maximum parsimony
assumes that the tree that requires the fewest evolutionary events (appearances of shared derived characters) is the most likely
Maximum likelihood
states that, given certain rules about how DNA changes over time, a tree can be found that reflects the most likely sequence of evolutionary events
The best hypotheses for phylogenetic trees fit the __________
most data: morphological, molecular, and fossil
Phylogenetic bracketing allows us to…
predict features of an ancestor from features of its descendants
Comparing __________ or other molecules to infer relatedness is a valuable approach for tracing organisms’ evolutionary history
nucleic acids
_______ that codes for _______ changes relatively slowly and is useful for investigating branching points hundreds of millions of yeas ago
DNA; rRNA
_______ evolves rapidly and can be used to explore recent evolutionary events
mtDNA
Gene duplication
increases the number of genes in a genome, allowing for more opportunities for evolutionary change
T/F: Gene number and the complexity of an organism are not strongly linked
True
molecular clock
uses constant rates of evolution in some genes to estimate the absolute time in evolutionary change
orthologous genes
genes in different species that share a common ancestor
paralogous genes
genes that are copies of each other, created by gene duplication
