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.
These six mass extinctions are alike in some ways. They all represent the extinction of a significant component of global faunas and/or floras, and they are all relatively sudden in geological terms: that is, they occurred over a few million years at most, and in some cases much less than that.