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. It 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 either 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, representing a single branch on the tree of life.
Phylogenetic tree: A branching diagram or "tree" showing the inferred evolutionary relationships among various biological species or other entities—their phylogeny—based upon similarities and differences in their physical or genetic characteristics.
DNA sequence alignment: A way of arranging the sequences of DNA, RNA, or protein to identify regions of similarity that may be a consequence of functional, structural, or 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 on the basis of 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 (barriers) that impede members of two species from interbreeding and producing viable, fertile 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 (fertilized egg).
Geographic isolation: A form of reproductive isolation in which two populations are separated physically by geographic barriers such as rivers, mountains, or stretches of ocean.
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 of animals or plants.
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 other 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 that proposes that species evolve slowly and steadily through a series of intermediate forms.
Mass extinction: A relatively sudden, global decrease in the diversity of life forms.
Punctuated equilibrium: A model of evolution that proposes that species undergo relatively rapid periods of evolutionary change interspersed with long periods of stasis (little or no change).