Pros: 1  Works equally well in open terrain, under cover or in a gym. 2  Accurate on flat or hilly terrain and when making quick, sharp turns (e.g., when trail running or on an indoor track). 3  Lightweight design is sleeker than most GPS-enabled SDMs.
Definitions for mass extinction. Here are all the possible meanings and translations of the word mass extinction. Wiktionary(0.00 / 0 votes)Rate this definition: mass extinction(Noun) A sharp decrease in the total number of species in a relatively short period of time.
Mass extinctions are usually associated with organisms that are macroscopic rather than microscopic. Examples of mass extinctions are Permian extinction of marine species, and Cretaceous extinction of various species, including dinosaurs. Synonym(s): 1  extinction event. 2  extinction-level event. 3  biotic crisis.