Chapter 23: Understanding Diversity - Systematics Flashcards

Vocabulary practice flashcards generated from the Biology Chapter 23 lecture notes covering systematics, taxonomy, classification, cladograms, molecular homologies, and phylogenetic trees.

Taxonomy

The science of naming, describing, and classifying organisms.

Classification

Arranging organisms into groups based on similarities that reflect evolutionary relationships among lineages.

Carcharias taurus

The scientific name for the shark species known by various common names including sand tiger shark, grey nurse shark, spotted ragged-tooth shark, blue-nurse sand tiger, Tiburón toro, and Toro bacota.

Felis concolor

The scientific name for the species also referred to by common names such as cougar, mountain lion, catamount, puma, and panther.

Binomial System of Nomenclature

A two-part naming system simplified by Carolus Linnaeus where each species is assigned a unique name consisting of a genus and a specific epithet.

Specific Epithet

The second part of a binomial scientific name that designates a specific species within a genus.

Taxon

A formal named group of organisms at any level of classification.

Linnaean Hierarchy Ranks

The sequence of taxonomic ranks arranged from broadest to most specific: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Classification of Corn (Zea mays)

The hierarchical taxons for corn: Domain Eukarya, Kingdom Plantae, Phylum Anthophyta, Class Monocotyledones, Order Commelinales, Family Poaceae, Genus Zea, Species Zea mays.

Procariotique and Eucariotique

Terms proposed in 1937 by French marine biologist Edouard Chatton to distinguish organisms before nucleus and with a true nucleus, now translated as prokaryotic and eukaryotic.

Whittaker Five-Kingdom System

A classification scheme proposed in 1969 by R. H. Whittaker based on cell structure and mode of nutrition, dividing organisms into Bacteria, Archaea, Plantae, Fungi, and Animalia.

Three-Domain System

A domain classification introduced by Carl Woese in the 1970s based on ribosomal RNA gene sequences, splitting prokaryotes and eukaryotes into Domain Bacteria, Domain Archaea, and Domain Eukarya.

Clade

A group consisting of a common ancestor and all of its descendants.

Cladogram

A branching diagrammatic phylogenetic tree in which each branch represents a clade sharing a common ancestor.

Node

A branching point on a phylogenetic tree that represents the divergence of two or more new groups from a common ancestor.

Root

The node at the base of a cladogram representing the most recent common ancestor of all clades depicted in the tree.

Vertical Gene Transfer

The transmission of genes and DNA inherited from a parental organism to its offspring within the same species across generations.

Horizontal Gene Transfer

The movement of genetic material between different species or unrelated organisms in the same generation, such as through endosymbiosis.

Homology

The existence of shared traits or structures inherited from a common ancestor as a product of divergent evolution.

Convergent Evolution

The process by which unrelated species independently evolve similar adaptation traits when exposed to similar environmental conditions.

Homoplasy

A structural or phenotypic character that appears similar between species but was acquired through convergent evolution or reversal rather than shared ancestry.

Evolutionary Reversal

A process in which a derived character state reverts back to its ancestral trait state.

Shared Ancestral Character (Symplesiomorphy)

A primitive feature present in an ancestral species that remains present in all groups descended from that remote common ancestor.

Shared Derived Character (Synapomorphy)

A novel trait that evolved in a recent common ancestor and is shared by its descendant species, forming points where groups diverged.

Plesiomorphy

A primitive or ancestral character state.

Apomorphy

A derived character state that differs from the primitive ancestral state.

Molecular Systematics

A field of systematics that analyzes molecular structures, such as nucleotide or amino acid sequences, to determine evolutionary relationships.

DNA Barcode Project

An effort to identify species using a standardized, short, easily sequenced region of DNA that possesses a unique sequence of nitrogenous bases for each species.

Molecular Clock

A comparison tool utilizing macromolecules that accumulate changes at a steady rate to estimate the elapsed time since two lineages diverged from a common ancestor.

Monophyletic Group

A taxon or clade consisting of an ancestral species and all of its descendants.

Paraphyletic Group

A taxon that contains a common ancestor and some, but not all, of its descendants.

Polyphyletic Group

A group consisting of several evolutionary lines that do not share the same recent common ancestor, formed due to homoplasy.

Principle of Parsimony

A guideline stating that when evaluating competing cladograms, the simplest explanation requiring the fewest character changes should be accepted as most probable.

Homology vs. Homoplasy Cladograms

Homology represents similar traits inherited directly from a common ancestor, whereas homoplasy represents similar traits that are not directly caused by common ancestry (convergent evolution).

Amniote Skull Morphs

The three skull structural types characterized by temporal openings: Anapsid skull, Synapsid skull, and Diapsid skull.