Classification of Life & Biodiversity - Vocabulary Flashcards

Vocabulary flashcards covering key concepts from the notes on classification, biodiversity, taxonomy, and evolutionary relationships.

Biodiversity

The variety of life in all its forms, levels, and combinations; notes indicate biodiversity is declining rapidly worldwide.

Species

The basic unit of classification; its precise definition is still debated.

Taxonomy

Branch of biology concerned with naming and classifying organisms.

Carolus Linnaeus

Scientist who developed the binomial nomenclature system still used today.

Binomial nomenclature

Two-part scientific naming system: genus name (capitalized) + specific epithet (lowercase); always italicized.

Genus

The first part of a binomial name; a capitalized group that includes related species.

Specific epithet

The second part of a binomial name; lowercase; together with the genus forms the species name.

Taxon

Any named group at any level of classification.

DKPCOFGS

Acronym for Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species (hierarchical ranks).

Hierarchical Classification

Organization of life from broad to narrow categories.

Domain

The broadest taxonomic level in the current system.

Three Domains of Life

Bacteria, Archaea, and Eukarya—the highest taxonomic ranking.

Bacteria

Diverse and widespread prokaryotes.

Archaea

Prokaryotes that often live in extreme environments.

Eukarya

Domain of all eukaryotes, including plants, animals, fungi, and protists.

Prokaryotes

Cells without a nucleus or membrane-bound organelles; usually smaller.

Eukaryotes

Cells with a nucleus and membrane-bound organelles; typically larger.

Protists

Mostly unicellular eukaryotes; not a single kingdom and include various forms.

Plantae

Multicellular, photosynthetic, autotrophic eukaryotes.

Fungi

Heterotrophic organisms that absorb nutrients; can be unicellular or multicellular.

Animalia

Multicellular, heterotrophic organisms that ingest food.

LUCA

Last Universal Common Ancestor of all life.

Phylogenetic tree

Diagram showing hypothesized evolutionary history of species.

Cladogram

Branching diagram showing relationships without time or genetic distance.

Systematics

Science that classifies organisms and determines evolutionary relationships.

Morphological similarities

Physical features used to infer relationships.

Fossil evidence

Fossils used to infer evolutionary relationships.

Molecular similarities

DNA/protein data used to infer evolutionary relationships.

Evolutionary relationships

Connections among species based on common ancestry.

Monophyletic

An ancestor and all of its descendants (a clade).

Paraphyletic

An ancestor and some, but not all, of its descendants.

Polyphyletic

Unrelated species that do not share the most recent common ancestor.

Systematics (rephrase)

Discipline combining morphology, fossils, and molecular data to map evolution.

Key historical shifts

Classification changes: originally two kingdoms, 1969 five kingdoms, 1990 three-domain system.

Monera

One of the five kingdoms in 1969, primarily bacteria and related organisms.

Protista (five-kingdom system)

One of the five kingdoms in 1969, comprising diverse mostly unicellular organisms.

Five-kingdom system

Classification used until the 1990s: Monera, Protista, Plantae, Fungi, Animalia.

Three-domain system

Modern classification adopted in 1990: Bacteria, Archaea, Eukarya.

Insect microbiome

Each insect species may host many unique bacteria.

Estimated total species

The true number of species likely falls between 5 and 10 million.

Autotrophs

Organisms that produce their own food, typically through photosynthesis or chemosynthesis (e.g., plants).

Heterotrophs

Organisms that obtain nutrients by consuming other organisms or organic matter; they cannot produce their own food.

Clade

A group consisting of an ancestor and all of its descendants; a monophyletic group on a phylogenetic tree.

Key characteristics of Prokaryotes

Cells characterized by the absence of a nucleus and other membrane-bound organelles; generally smaller than eukaryotes.

Key characteristics of Eukaryotes

Cells distinguished by the presence of a membrane-bound nucleus and various membrane-bound organelles; typically larger than prokaryotes.