Chapter 2: Systematic procedures Flashcards
The fundamental unit of classification schemes
Species
What is a morphospecies?
A species designated and clearly separated from other species based on recognized unequivocal morphological features.
The concept that species are groups of actually or potentially interbreeding populations which are reproductively isolated from other such groups
the biological species concept
________ deals with the theory and practice of describing biodiversity, arranging this diversity into a system of classification, and devising identification keys. It includes the rules of nomenclature that govern use of taxonomic names.
Taxonomy
________ emphasizes the study of relationships postulated to exist among species or higher taxa, such as families or orders.
Systematics
What is an apomorphy?
A recently evolved, derived, or advanced character.
What is a pleisomorphy?
A more ancestral, primitive, or generalized character.
What is a synapomorphy?
A shared derived character.
What are monophyletic groups (or clades)?
Groups containing an ancestor and all it descendant taxa.
What is a symplesiomorphy?
A shared primitive character.
What is an autapomorphy?
A specialized character that is present in only a single taxon.
What are sister groups?
The most closely related clades in the nodes of a cladogram.
What are homoplasies?
Shared, independently derived similarities.
What are polyphyletic groups?
Groups containing the descendants of different ancestors.
What are paraphyletic groups?
Groups that do not contain all the descendants of a single ancestor.
What are grades?
Groups that are defined by their morphological or ecological distinctness and not necessarily by synapomorphies.
What are meristic characters?
Almost any countable structure, including numbers of scales, gill rakers, cephalic pores, and so on. They are clearly definable, and usually other investigators will produce the same counts.
What are morphometric characters?
Measurable structures such as fin lengths, head length, eye diameter, or ratios between such measurements. They are sometimes hard to define exactly, and being continuous variables, they can be measured to different levels of precision and so are less easily repeated.
What are anatomical characters?
Characters of the skeleton and soft anatomy, such as the position of the viscera, divisions of muscles, and branches of blood vessels.
