Topic 7- Systematics Flashcards
Sysematics
The science of classifying organisms and determining their evolutionary relationships
Two component of systematics: Taxonomy
The scientific discipline of naming and classifying organisms
-The science of classifying organisms by describing and naming by species/genus.
-For example: humans and whales are two unrelated organisms from different perspectives; however, both are considered mammals and taxonomically related.
Two component of systematics: Phylogenetics
the study of evolutionary relationships
Phylogentic tree
A diagrammic hypothesis of evolutionary relationships of a group of organisms that results from phylogentics analysis
Understanding phylogenetic tree: Monophyletic
group is composed of an ancestral species and ALL of its descendants
Understanding phylogenetic tree: Paraphyletic
group contains a common ancestor and some, but not all, of its descendants
Understanding phylogenetic tree: Polyphyletic
group lacks the common ancestor of all its members
Cladistics
An approach to systematics in which common ancestry is the primary basis for classifying organisms (i.e. homology)
Two types of trees: Cladograms
Show only the branching pattern with no information about timing or amount of change (i.e. branch lengths are arbitrary)
Two types of trees: Phylograms
show branching patterns AND branch lengths are proportional to either the amount of genetic change or the times of the various branching points
