Glossary: biodiversity patterns of speciation and extinction

All of the following terms appear in the videos or articles for this tutorial on biodiversity patterns of speciation and extinction. The terms are arranged here in alphabetical order, and nouns are given in just their singular form unless the plural of the term is unusual.

adaptation: a physical or behavioral trait of an organism that makes it well-suited to its environment and more likely to survive and reproduce

anoxic: lacking oxygen

Anthropocene: the present epoch of geologic time dominated by humans; anthro is for human; cene is the suffix used to designate an epoch

archipelago: a group of islands

background rate: in general terms, the naturally occurring rate of something; the background rate for species extinction is calculated from times before human activities greatly altered the environment and is estimated to be one to five extinctions a year averaged over geologic time

biodiversity: the variety of life on Earth or some specified geographic area of the planet; the diversity of life occurs at the genetic level, at the species level, at the ecosystem level, and in evolutionary lineages

bolide: an asteroid, comet or meteor that hits the surface of a planet

colonization: species reaching and successfully occupying new areas

Cretaceous: the geologic period approximately 145-65 million years ago when dinosaurs dominated the planet; abbreviated "K" in scientific works

dispersal:  in general terms, the scattering or spreading of something; in biological terms, how individuals or their offspring get from one location to another; dispersal can extend the range of a species

divergence: in general terms, branching in different directions; in evolution, the accumulation over time of increasing genetic differences between two populations whose former gene flow has been restricted for some reason; divergence can lead to speciation

ecosystem:  the community of different species in a particular geographic area and all of their interactions with each other and the physical environment; ecosystems are also called ecological networks

ecosystem services:  the ways in which intact ecosystems benefit humans; these services can be direct, indirect or related to aesthetic and ethical values

epoch: an interval of geologic time that is a subdivision of a period

endemic:  a term used to describe a species that occurs in only one specific, restricted geographic area; all endemic species are also native to their area, but not all native species qualify as endemic

era: an interval of geologic time that is a subdivision of an eon

evolution: change in heritable traits of a population over time

evolutionary: related to evolution, the changes in heritable traits of a population over time

extinction:  the loss of a species completely and forever; happens when the last living member of a species dies

fossil: an organism, part of an organism or trace evidence of an organism such as a footprint, that is preserved in rock

fossil record: all of the fossils that have been found, also used in reference to the complete set of fossils of a specific taxon

gene: a segment of DNA at a specific location on a chromosome that is the basic unit of heredity

gene flow: movement or sharing of genes within and between populations due to reproduction among members of the populations

genetic variation: differences in the DNA of the members of a population or species; genetic diversity

genera (plural; singular = genus): the taxonomic rank between species and family; the genus name constitutes the first element of the scientific name in binomial nomenclature

Gondwana:  the southern supercontinent, formed in Precambrian time, that existed up to approximately 200 million years ago when it started breaking up in stages due to plate tectonics; comprised present day South America, Africa, Arabia, Australia, Antarctica, Madagascar, India and New Zealand; also called Gondwanaland

greenhouse effect:  the warming of Earth’s atmosphere by solar radiation that is trapped in the form of heat by various gasses in the atmosphere

habitat: a general term for the type of environment in which an organism lives

invertebrate: an animal without a backbone

island biogeography: the study of which species occur on different islands, which is a function of the size of the island and its distance from other land, especially the nearest island or continent

larva:  the immature stage of an animal that does not look like the adult stage; undergoes a change or metamorphosis to assume the adult form (e.g., caterpillar becoming a butterfly); plural = larvae

mass extinction event:  a time when there was a significant drop in the biodiversity on Earth, when the extinction rate was well above the background rate; there were five major mass extinction events in earlier geologic time, and humans are now causing a sixth one

metamorphosis:  during animal growth, the change from the larval form into the early adult form

methane: CH4; one of the greenhouse gases; a primary component of natural gas

methane clathrate:  a lattice formed from water molecules in ice-like form in which significant amounts of methane can be trapped; known to occur in and on the ocean floor

parasite: an organism that benefits by living in or on a host, another organism that is harmed by the parasite

period: an interval of geologic time that is a subdivision of an era

population: all the individuals of a particular species that live in a specific geographic area; a species may be made up of one or more populations

population size: the number of individuals in a particular population of organisms

predator:  an organism that hunts, catches, kills, and eats other animal

range:  the geographic places or areas around the world in which a species lives; similar to the distribution of the species

speciation: the formation of new species; occurs when one species gives rise to two new species due to the restriction of gene flow

species: a distinct type of organism

species richness: the number of different species in a given geographic area

vicariance model: speciation that occurs when a species is split into separated populations between which gene flow is restricted; usually the split occurs because of physical barriers that arise between the populations; these isolated populations can diverge over time and become new species

volcanism: volcanic activity; also spelled vulcanism