Invasive species, also called invasive exotics or simply exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions.

Because of the variability of its definition, and because definitions are often from a socioeconomic perspective, the phrase invasive species is often criticized as an imprecise term for the scientific field of ecology. This article concerns the first two definitions; for the third, see Introduced species.

Scientists include species- and ecosystem factors among the mechanisms, that when combined establish invasiveness in a newly introduced species.

While all species compete to survive, invasive species appear to have specific traits or specific combinations of traits that allow them to outcompete native species. In some cases the competition is about rates of growth and reproduction. In other cases species interact with each other more directly.

Researchers disagree about the usefulness of traits as invasiveness markers. One study found that of a list of invasive and noninvasive species, 86% of the invasive species could be identified from the traits alone. Another study found invasive species tended only to have a small subset of the presumed traits, and that many such traits were found in noninvasive species, requiring other explanations. Common invasive species traits include:

Jonathan Bird's Blue World is an educational television program about the underwater world. The show is hosted by underwater cinematographer Jonathan Bird. This series airs on PBS stations in the US. The program is designed for family viewing, and each segment finds Bird trying to unravel a mystery, witness an animal behavior or explore an underwater environment. The first season consisted of 5 half-hour programs filmed in standard definition, and the second season contained 7 half-hour programs shot in high-definition. The second season won four New England Emmy Awards. The pilot episode from season 1 won a CINE Golden Eagle Award. Season three consists of 9 half-hour programs in HD and will be released August 29, 2011. The program is magazine format with each television episode consisting of 2-3 segments. These segments appear individually on the Blue World website as webisodes.

Episode 1: Blue Shark Adventure, Underwater Cavern, Giants of the Depths

Episode 2: Swimming with Jaws, The Bandana Game, The Shark and the Whale