Biology 20: Unit B - Population Change Flashcards

Vocabulary practice flashcards covering key mechanisms, evidence, and modern theories of population change and evolution.

Evolution

The gradual change in the characteristics of a population of animals or plants over many generations.

Natural Selection

The mechanism by which evolution occurs, acting on individuals with favorable traits that make them more likely to survive, reproduce, and pass those traits to offspring.

Paleontology

The scientific study of fossils.

Burgess Shale

A fossil site located in British Columbia containing exceptional fossil evidence from the Cambrian period.

Transitional Fossil

Fossils that exhibit traits intermediate between an ancestral form and its descendants, helping fill gaps in the fossil record.

Archaeopteryx

A transitional fossil between reptiles/dinosaurs and birds.

Radiometric Dating

A technique used to determine the exact age of fossils by measuring the decay of radioactive isotopes.

Carbon-14 Half-Life

The duration of time needed for half of the Carbon-14 isotope in an organism to decay after death, which is $5,730\,\text{years}$.

Relative Dating

A process that determines the sequential order of a series of events or fossil layers without assigning an exact numerical age.

Index Fossils

Fossils of known age used to define and identify specific geologic periods.

Homologous Structures

Anatomical features in different species that share a common evolutionary origin and structural arrangement, but may serve different functions.

Analogous Features

Anatomical structures in different species that perform similar functions and look similar, but lack a common evolutionary origin.

Vestigial Features

Anatomical structures that have no functional role in modern organisms but were functional in an ancestral form.

Comparative Embryology

The analysis of developing embryos across different species to reveal structural similarities that imply common ancestry.

Artificial Selection

The deliberate process of humans selecting and breeding individual organisms that exhibit specific desirable traits.

Gradualism

A model of evolution stating that evolutionary changes occur steadily and linearly through small, continuous steps over long periods of time.

Punctuated Equilibrium

A model of evolution stating that long periods of evolutionary equilibrium are interrupted by sudden, rapid periods of speciation.

Speciation

The formation of two or more distinct species from a single ancestral population.

Transformation (Evolutionary)

An evolutionary pathway where one species gradually changes into another over time, replacing the original parent species.

Divergence (Evolutionary)

An evolutionary pathway where one or more new species branch off from a parent species that continues to exist.

Geographical Barriers

Physical obstacles like rivers or mountains that physically isolate populations, leading to independent evolutionary paths.

Biological Barriers

Non-physical factors (such as behavioral mating rituals or distinct habitats) that prevent interbreeding between overlapping populations.

Adaptive Radiation

The rapid diversification of a single ancestral species into a variety of differently adapted species.

Phylogeny

The evolutionary history and ancestral lineage of an organism or group of organisms.