Phylogeny, Speciation, and Population Genetics Flashcards

Vocabulary flashcards covering population and tree thinking, phylogenetics, domain systems, speciation, scale and deep time, the Luria-Delbrück fluctuation test, antibiotic resistance dynamics, and Hardy-Weinberg equilibrium.

Population Thinking

A perspective in evolutionary biology emphasizing that individual variation within a species is the ongoing outcome of mutation, recombination, phenotype production in available environments, and natural selection across generations.

Tree Thinking

A scaling-up of population thinking that conceptualizes species as interrelated entities connected by past evolutionary events, represented and analyzed through phylogenetic trees.

Cladogram

A diagram depicting evolutionary relationships among taxa, where the branching pattern (tree topology) represents kinship and the horizontal left-to-right order of species nodes is irrelevant.

Monophyletic Group

A clade or biological grouping consisting of an ancestral species and the complete set of all its descendants.

Paraphyletic Group

An evolutionary grouping that consists of an ancestral species and only some, but not all, of its descendants.

Rhopalium

A specialized sensory structure in box jellyfish (such as Tripedalia cystophora) housing photosensors, lensed eyes, and a statolith.

Statolith

A floating crystal weight inside a box jellyfish rhopalium that maintains the orientation of the upper lensed eye so it consistently points upward.

Five-Kingdom System

An obsolete biological classification scheme that placed all prokaryotic unicellular organisms into Kingdom Monera alongside Protista, Plantae, Fungi, and Animalia.

Three-Domain System

A taxonomic framework established by Carl Woese that categorizes all cellular life into three primary domains above the kingdom level: Bacteria, Archaea, and Eukarya.

Small Ribosomal Subunit RNA (rRNA)

A universally present, slowly evolving molecular marker utilized by Carl Woese to discover Domain Archaea and measure phylogenetic divergence across organisms.

Primary Endosymbiosis

An evolutionary process in which an ancestral heterotrophic eukaryotic host cell engulfs a free-living prokaryote, which eventually evolves into an organelle such as a mitochondrion or plastid.

Secondary Endosymbiosis

An evolutionary process wherein a heterotrophic eukaryote engulfs a photosynthetic eukaryotic algal cell (such as a red or green alga) that has already undergone primary endosymbiosis.

Biological Species Concept

A species concept formulated by Ernst Mayr defining a species as a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring.

Binomial Nomenclature

A formal two-part system for naming species that combines the genus name with a specific epithet (for example, Ursus maritimus).

Anchor Points

Domain-specific conceptual indexes derived from experience that assist individuals in navigating and understanding physical or temporal scales.

Deep Time

The vast multi-million to multi-billion-year geological timescale required to comprehend macroevolutionary events and history.

Fluctuation Test

A classic 1943 experiment performed by Salvador Luria and Max Delbrück demonstrating that beneficial mutations in bacteria occur randomly before selection rather than being induced by environmental stress.

Spontaneous Mutation Hypothesis

The validated evolutionary model stating that beneficial genetic variants pre-exist randomly in a population before selection acts upon them.

Induction Mutation Hypothesis

The disproven hypothesis asserting that environmental influences directly direct or induce specific advantageous mutations in response to stress.

Distribution of Fitness Effects (DFE)

The spectrum or variability of fitness impacts resulting from mutations across a population under specified environmental conditions (also called fitness variability).

Resistance Variability

A system-level property describing the range or diversity of mutational pathways accessible to an organism to gain drug resistance.

Morbidostat

An automated culture device that continually measures population density and adjusts drug inflow to maintain constant growth inhibition as microbial resistance evolves.

Evolutionary Pattern

The observational data, facts, and biological phenomena over time that reveal evolutionary change.

Evolutionary Process

The underlying mechanisms (such as natural selection, genetic drift, or gene flow) that cause observed patterns of biological change.

Adaptation

A heritable characteristic that enhances an organism's survival and reproductive success in its current environment.

Vitamin K Epoxide Reductase Complex (VKORC)

An enzyme complex responsible for converting vitamin K 2,3 epoxide to vitamin K hydroxyquinone during coagulation factor synthesis, which is targeted and inhibited by warfarin.

Hardy-Weinberg Equilibrium

A mathematical model predicting that allele and genotype frequencies remain constant across generations in a non-evolving population, described by $p + q = 1$ and $p^2 + 2pq + q^2 = 1$.

Genetic Drift

An evolutionary mechanism consisting of unpredictable, random changes in allele frequencies from generation to generation, most prominent in small populations.

Gene Flow

The transfer of alleles into or out of a population caused by the movement of fertile individuals or their gametes.