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.
1 Hypothesis: Changes in the Earth's climate caused the mass extinction. 2  This could have been caused by gradual changes in the positions of continents effecting ocean currents and winds, or by changes in the Earth's orbit around the sun, or even by a relatively sudden greenhouse effects.