Extinction events

Sagan 4 has had many general extinction events over the years. Though most of what one would want to know about Alpha's extinction events is covered in the Geologic Timescale, this page serves to cover the community side of things regarding certain extinction events. This does not include species-caused local events, which are covered in plagues.

Alpha

Early Extinction Events

The first two extinction events--the first solar flare and the first ice meteor--were part of the original concept of Sagan 4, that there would be a mass extinction at the end of every week. This was abandoned due to it being difficult for biodiversity to increase with how small the generations were.

Gamma Ray Burst

The gamma ray burst did not have significant meta reasons for happening, apart from it being generation 100, which was considered a good time for a mass extinction. It is also the mass extinction with the most "metagaming" associated with it--when browsing through species from the last few generations before it occurred, one will see a very large number of species moving into caves or the deep sea or becoming burrowers, as the extinction event had been announced beforehand and many members desperately scrambled to save as many things as they could. There was also some controversy surrounding the gamma ray burst, as many members were upset that their species had died and some considered it to be "unfair".

Ice Comet

The ice comet which struck at the beginning of week 19 was meant to be a "completely fair" extinction event which simply wiped out everything over 1 meter in size. However, this too was controversial because it resulted in a mass extinction of plants; most famously, iconic planimals such as tree plents and worm flora were completely wiped out. Some members believed they should have survived because of seeds or spores germinating after the dust had cleared from the impact event. However, it is also important to note that based on a similar impact event on Earth, the one which occurred on Sagan 4 actually very realistically could have caused the flora turnover that it did.

Ice Age and Snowball Event

The ice age and snowball event partially served to wipe out implausible organisms. As long as members were not allowed to evolve from them, the massive grind of habitat loss--which ultimately completely turned over all biomes apart from some tundra in Darwin and Drake--could therefore take out the vast majority of implausible organisms.

As part of this, Clarke created the No-Snarf to wipe out the vast majority of Nodents, one of the lineages that had been deemed implausible. Ironically, the species which he would diversify to take over their niches--the Land Swarmers--turned out to themselves be completely implausible and had to be mostly wiped out at the end of the snowball event.

Beta

The Beta timeline, being much younger than Alpha, has had fewer extinction events.

Coronal Mass Ejection

The coronal mass ejection was a reimagined version of Alpha's first mass extinction event, where the planet's magnetic field was compromised by an event far more powerful than a solar flare. All extinction results were also re-rolled, resulting in slightly more survivors--but they were heavily biased in favor of microbes and binucleids, with more binucleids surviving than in Alpha and the only other multicellular life to make it through being Carpotesta Luceremundere. This change defined Beta's early ecosystems, which became completely dominated by worms and crystal flora.

End-Binucleozoic Atmospheric Disturbance (EBAD)

Although the drop in oxygen levels was the inevitable result of increasing volcanism, the sheer destructive power of EBAD was directly caused by the early dominance of crystal flora on land, which resulted in significant amounts of previously-bioavailable nitrogen becoming locked away in chitinous flora which did not rot before being buried. This ultimately disrupted the nitrogen cycle and caused a mass extinction of flora, as well as taking out all megafaunal worms--even ones with unidirectional lungs which could have otherwise survived the dip in oxygen unscathed. Most non-binucleid flora and fauna were too small to be affected, even those much bigger than the largest surviving binucleids, resulting in a significant faunal and floral turnover.