Glossary: biodiversity and the tree of life

All of the following terms appear in the videos or article for this tutorial on genetic and ecosystem biodiversity. 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.

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

biomass: the weight (that is, the mass) of living organisms in a given area

cladogram: a branching diagram illustrating the evolutionary history and relationships of species based on shared, advanced characters; also known as a phylogenetic tree or tree of life

common ancestor: the ancestral species from which two different species evolved

conservation: in a biological context, the management of natural resources to help ensure their long-term sustainability

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 diversity: distinct types of global ecosystems such as tropical coral reefs, Arctic tundra, or tropical rainforest, combined with the unique regional diversity of species within a single, specific type of ecosystem (e.g., tropical rainforests in Central America versus those in Africa versus those in southeast Asia)

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

evolution: change in heritable traits of a population over time

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

evolutionary lineage: a group of species descended from a common ancestral species; it represents a branch or series of branches on the evolutionary tree of life

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

genetic diversity: genetic variation; can refer to genetic variability among individuals within a single population, among populations comprising a single species, or among different species

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

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

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

hypothesis: in science, a working explanation or assumption based on observed facts and that leads to testable predictions

mass extinction: significant loss of species well above the background rate of extinction

phylogenetic systematics: a method of classifying species based on the study of evolutionary relationships and shared characters among the species

phylogenetic tree: a branching diagram illustrating the evolutionary history and relationships of species based on shared, advanced characters; also known as a cladogram or tree of life

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

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

topology: the configuration or shape of something; in phylogenetic trees, any given branching pattern of a phylogenetic tree (cladogram)

tree of life: a branching diagram illustrating the evolutionary history and relationships of species based on shared, advanced characters; also known as a cladogram or phylogenetic tree