Classification and Systematics Flashcards

Vocabulary flashcards reviewing core terms and concepts in biological classification, systematics, taxonomy, cladistics, Euglenophyta, and Pyrrophyta.

Classification

The systematic arrangement of organisms into groups based on their similarities, differences, and evolutionary relationships.

Taxonomy

The science concerned with the identification, nomenclature, and classification of organisms.

Identification

The aspect of taxonomy concerned with determining what a given organism specimen is.

Nomenclature

The aspect of taxonomy concerned with assigning a scientific name to an organism.

Systematics

A broad biological field involving the study of organismal diversity, relationships, evolutionary history, classification, identification, and nomenclature.

Binomial Nomenclature

A naming system where a scientific name consists of two parts: a capitalized genus and a lowercase specific epithet, written in italics or separately underlined when handwritten.

Atropa belladonna L.

A species in the family Solanaceae with the common name Deadly Nightshade; its genus is named after the Greek Fate Atropos (referring to toxicity) and its specific epithet means 'beautiful lady' in Italian (referring to pupil-dilating cosmetic use).

Major Hierarchy of Biological Classification

The plant-oriented hierarchical levels of taxonomy: Domain, Kingdom/Phylum, Angiosperms/Division, Class, Order, Family, Genus, and Species.

Cladistics

A classification method that groups organisms according to their evolutionary relationships, particularly their shared derived characteristics.

Clade

The fundamental unit of cladistic analysis, consisting of an ancestor and all of its descendants.

Character (Cladistics)

A feature used to compare organisms in cladistics, such as the presence of vascular tissue, seeds, or spore structures.

Character State

The specific expression or condition of a character in cladistics, such as vascular tissue being present or absent.

Ancestral Character

A characteristic inherited from an earlier ancestor.

Derived Character

A characteristic that evolved more recently within a particular lineage.

Synapomorphy

A shared derived characteristic present among organisms that indicates membership in the same clade.

Cladogram

A branching diagram showing hypothesized evolutionary relationships among organisms.

Artificial Classification

A classification system grouping organisms using a limited number of easily observable characteristics, such as habitat, color, or growth form.

Natural Classification

A classification system utilizing many characteristics—such as morphology, anatomy, physiology, embryology, and biochemistry—to reflect natural relationships.

Phylogenetic Classification

A classification system based primarily on evolutionary history and common ancestry using morphology, anatomy, and molecular DNA/RNA sequences.

Algae

Relatively simple, predominantly aquatic photosynthetic organisms containing chlorophyll or other photosynthetic pigments, ranging from microscopic unicellular forms to macroscopic multicellular forms.

Division Euglenophyta

A division of mostly unicellular freshwater algae represented primarily by Euglena.

Euglena

A representative euglenoid organism featuring a spindle-shaped body, pellicle, flagellum, chloroplasts, nucleus, contractile vacuole, and an eyespot.

Pellicle

A flexible cell membrane structure in Euglena that provides support while allowing the organism to change shape.

Eyespot (Stigma)

A specialized structure in Euglena that detects light and aids in phototaxis.

Mixotrophic Nutrition

A nutritional capability combining autotrophic photosynthesis when light is present and heterotrophic organic nutrient absorption under other conditions.

Division Pyrrophyta

An algal division that traditionally includes dinoflagellates such as Ceratium, Gonyaulax, Noctiluca, and Dinophysis.

Ceratium

A representative unicellular dinoflagellate belonging to Division Pyrrophyta.

Transverse Flagellum

A flagellum located in a groove around a dinoflagellate cell that works with a longitudinal flagellum to produce a spinning motion.

Longitudinal Flagellum

A flagellum that extends posteriorly from a dinoflagellate cell to assist in movement.

Red Tides

Harmful algal blooms caused by certain dinoflagellates that result in water discoloration, fish mortality, and toxin accumulation in shellfish.