Macroevolution, Origin of Life, and Earth's Geological History

A complete set of vocabulary flashcards covering evolutionary patterns, the endosymbiotic theory, and Earth's geological processes and timescale.

macroevolutionary pattern

A grand transformation in anatomy, phylogeny, ecology, and behavior that occurs in clades larger than a single species over long periods of time.

extinct

The state of a species that has completely died out and no longer has any living members.

background extinction

The ongoing, slow, and steady process of species extinction driven by natural selection and typical environmental changes.

mass extinction

An event during which many species become extinct across the globe over a relatively short period of geologic time.

gradualism

The evolutionary model proposing that evolution proceeds through a slow, steady, and continuous accumulation of small changes over time.

punctuated equilibrium

The evolutionary model describing long periods of evolutionary stability (equilibrium) interrupted by brief periods of rapid evolutionary change.

adaptive radiation

The process by which a single ancestral species or small ancestral lineage rapidly diversifies into many diverse forms adapted to different ecological niches.

convergent evolution

The process by which unrelated organisms independently evolve similar structures or traits as adaptations to similar ecological roles or environments.

coevolution

The process whereby two or more closely interacting species evolve reciprocal genetic changes in response to one another.

endosymbiotic theory

The theory proposing that eukaryotic organelles, such as mitochondria and chloroplasts, originated from free-living prokaryotes that entered into a mutually beneficial symbiotic relationship inside host ancestral cells.

crust

The thin, outermost solid rocky shell that forms the surface layer of Earth.

mantle

The thick middle layer of Earth located between the crust and the core, composed predominantly of hot, dense, semi-solid rock.

lithosphere

The rigid, brittle outer layer of Earth comprising the entire crust and the uppermost portion of the mantle.

core

The dense, central interior region of Earth, primarily consisting of an iron and nickel composition divided into a solid inner and liquid outer section.

plate tectonics

The scientific theory explaining how the large, rigid slabs of Earth's lithosphere move slowly over the asthenosphere, driving continental drift, earthquakes, and mountain formation.

weathering

The physical disintegration and chemical decomposition of rocks and minerals at or near Earth's surface by natural atmospheric and biological agents.

relative dating

A method used to determine whether a rock layer or fossil is older or younger than others without determining its exact numerical age.

index fossils

Distinctive, easily recognized, and geographically widespread fossils that existed for a brief span of geologic time, used to identify and date rock strata.

radiometric dating

A technique used to calculate the absolute age of rocks and fossils based on the fixed, steady breakdown rate of radioactive parent isotopes into stable daughter products.

half-life

The precise duration of time required for half of the radioactive atoms in a given isotope sample to undergo radioactive decay.

geologic time scale

A chronological framework that categorizes Earth's $4.6$-billion-year history into standardized divisions of eons, eras, and periods based on major geological and biological events.

era

A major division of geologic time encompassing two or more periods, usually bounded by profound worldwide changes in life forms.

period

A basic unit of geologic time that subdivides eras into distinct intervals characterized by specific fossil records and rock layers.