AP Biology

Evolution

The process by which different kinds of living organisms are believed to have developed and diversified from earlier forms during the history of the earth.

Biogeography

The study of the distribution of species and ecosystems in geographic space and through geological time.

Homologies (Homologous structures)

Structures in different species that are similar because of common ancestry.

Vestigial structures

Structures in an organism that have lost most or all of their original function in the course of evolution.

Fossils

The preserved remains or traces of ancient organisms.

Mutation

A change in the DNA sequence of an organism.

Eukaryotes

Organisms whose cells have a nucleus enclosed within a nuclear envelope.

Prokaryotes

Unicellular organisms that lack a nucleus or any other membrane-bound organelles.

Central dogma

The process by which the instructions in DNA are converted into a functional product; states that DNA is transcribed into RNA, which is then translated into protein.

ATP (Adenosine Triphosphate)

The primary energy currency of the cell; a molecule that carries chemical energy within cells for metabolism.

Endomembrane system

A network of membranes inside and around a eukaryotic cell, related through direct physical contact or by the transfer of membranous vesicles.

Endosymbiosis

A process through which early eukaryotic cells are believed to have engulfed prokaryotic cells, leading to the origin of certain organelles like mitochondria and chloroplasts.

Speciation

The formation of new and distinct species in the course of evolution.

Phylogeny

The evolutionary history and relationships among individuals or groups of organisms.

Phylogenetics

The study of evolutionary relationships among biological entities, often species, populations, or genes.

Cladogram

A branching diagram showing the cladistic relationship between a number of species.

Clades

A group of organisms that consists of a common ancestor and all of its lineal descendants.

Phylogenetic tree

A branching diagram showing the inferred evolutionary relationships among various biological species or other entities.

DNA sequence alignment

A way of arranging the sequences of DNA, RNA, or protein to identify regions of similarity that may indicate evolutionary relationships.

Morphology

The study of the form and structure of organisms and their specific structural features.

Taxonomy

The science of defining and naming groups of biological organisms based on shared characteristics.

Analogous structures

Structures in different species that perform a similar function but have evolved separately, thus do not share a common ancestral origin.

Extinction

The state or process of a species, family, or larger group becoming extinct (dying out).

Reproductive isolation

The existence of biological factors that impede members of two species from interbreeding and producing viable offspring.

Adaptive radiation

The diversification of a group of organisms into forms filling different ecological niches.

Species

A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding.

Prezygotic barrier

A reproductive isolation mechanism that occurs before the formation of a zygote.

Geographic isolation

A form of reproductive isolation in which two populations are separated physically by geographic barriers.

Post-zygotic barrier

A reproductive isolation mechanism that occurs after the formation of a hybrid zygote.

Hybrid

The offspring resulting from the interbreeding between two different species or varieties.

Gene flow

The transfer of genetic variation from one population to another.

Allopatric speciation

The formation of new species in populations that are geographically isolated from one another.

Sympatric speciation

The formation of new species in populations that live in the same geographic area.

Temporal isolation

A prezygotic barrier where two species breed during different times of day or different seasons.

Behavioral isolation

A prezygotic barrier where two species have different courtship rituals or behaviors that prevent mate recognition.

Mechanical isolation

A prezygotic barrier where morphological differences prevent successful mating.

Hybrid sterility

A postzygotic barrier where hybrid offspring are viable but infertile.

Gradualism

A model of evolution proposing that species evolve slowly and steadily through intermediate forms.

Mass extinction

A relatively sudden, global decrease in the diversity of life forms.

Punctuated equilibrium

A model of evolution proposing that species undergo rapid periods of evolutionary change interspersed with long periods of stasis.