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.
To a paleontologist, it means that at least 3 out of every 4 species on Earth disappear in a relatively short period of geologic time (which could be as long as a couple of million years, Barnosky said). Five mass extinctions have occurred so far in the history of life on Earth.