CH26 Flashcards
How were organisms first classified?
Classification of organisms based on morphological characteristics
It is now done on basis of molecular characteristics
Define
Phylogeny
Hypothesis for the evolutionary characteristics of a species/group of species
Define
Taxonomy
The scientific discipline of naming and classifying species
How are species named?
They are named in a binomial, all in italics. First, the genus and then the specific epithet
What is the order of taxons?
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
Dear King Peter Came Over For Good Soup
What are the elements found in a phylogenetic tree?
- Ancestral lineage (root)
- Basal taxon outgroup: early divergent
- Sister Taxa: two descendants of the same ancestor
- Branch points (internal nodes)
What is polytomy?
More than 2 descendant group emerging from a branch point, signals unresolved descendance pattern
Define
Homoplasies
Analogous structures that arose independently
Molecular homoplasy: same as above but at molecular level
Define
Cladistics
Approach to systematics based on common ancestry as primary criterion. Species are sorted into groups called clades
Define
Monophyletic group
Taxon, it is an ancestor and all its descendants. It is a clade
Define
Paraphyletic group
Group consisting of an ancestor and some of its descendants
Define
Polyphyletic group
Group consisting of distantly related species, excluding their common ancestor
Define
Shared ancestral character
Character that originated in an ancestor of the taxon
Define
Shared derived character
Evolutionary novelty unique to a clade
Define
Principle of Maximum Parsimony
Investing in the simplest explanation consistent with the facts
