Glossary of Terms for This Unit Section
- Adaptation: a structure, behaviour, or physiological process that helps an organism survive and reproduce in a particular environment
- Artificial selection: selective pressure exerted by humans on populations in order to improve or modify particular desirable traits.
- Biotechnology: the use of technology and organisms to produce useful products.
- Clade: a monophyletic group (= a branch on a cladogram).
- Cladogenesis: the evolutionary splitting of lineages, i.e. speciation.
- Cladogram: a branching diagram (tree) assumed to be an estimate of phylogeny.
- Extinct: describes a species that as completely disappeared from Earth.
- Fitness: the relative contribution an individual makes to the next generation by producing offspring that will survive long enough to reproduce.
- Ingroup: they study group whose phylogeny is being reconstructed.
- Lineage: a historical sequence of ancestors and descendants.
- Mimicry: a structural adaptation in which a harmless species resembles a harmful species in coloration or structure.
- Monoculture: extensive plantings of the same varieties of species over large expanses of land.
- Mutation: a permanent change in the genetic material of an organism; the only source of new genetic variation.
- Natural selection: the process by which characteristics of a population change over many generations as organisms with heritable traits survive and reproduce, passing their traits to offspring.
- Node: a branch-point on a tree/ cladogram.
- Outgroup: a terminal taxon (or group of taxa), preferably the sister-group of the ingroup, that is used to root a cladogram. The root is placed between the outgroup(s) and the ingroup. Multiple outgroups may be used.
- Selective advantage: a genetic advantage that improves an organism’s chance of survival, usually in a changing environment.
- Selective pressure: environmental conditions that select for certain characteristics of individuals and select against other characteristics.
- Taxon: a named group of organisms, not necessarily a natural (monophyletic) unit.
- Terminal (terminal taxon): one of the units whose collective phylogeny is reconstructed; in other words, the undivided tips of a tree.
- Variation: differences between individuals, which may be structural, functional, or physiological.