Sixth extinction? Why not? (Introduction)

by David Turell , Sunday, November 26, 2017, 15:16 (2553 days ago) @ David Turell

Extinction is part of evolution. Loss of a species is not wrong or a disaster:

https://www.washingtonpost.com/outlook/we-dont-need-to-save-endangered-species-extincti...

"Extinction is the engine of evolution, the mechanism by which natural selection prunes the poorly adapted and allows the hardiest to flourish. Species constantly go extinct, and every species that is alive today will one day follow suit. There is no such thing as an “endangered species,” except for all species. The only reason we should conserve biodiversity is for ourselves, to create a stable future for human beings. Yes, we have altered the environment and, in doing so, hurt other species. This seems artificial because we, unlike other life forms, use sentience and agriculture and industry. But we are a part of the biosphere just like every other creature, and our actions are just as volitional, their consequences just as natural. Conserving a species we have helped to kill off, but on which we are not directly dependent, serves to discharge our own guilt, but little else.

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"This is how evolution proceeds: through extinction. The inevitability of death is the only constant in life, and 99.9 percent of all species that have ever lived, as many as 50 billion, have already gone extinct. In 50 million years, Europe will collide with Africa and form a new supercontinent, destroying species (think of birds, fish and anything vulnerable to invasive life forms from another landmass) by irrevocably altering their habitats. Extinctions of individual species, entire lineages and even complete ecosystems are common occurrences in the history of life. The world is no better or worse for the absence of saber-toothed tigers and dodo birds and our Neanderthal cousins, who died off as Homo sapiens evolved. (According to some studies, it’s not even clear that biodiversity is suffering. The authors of another recent National Academy of Sciences paper point out that species richness has shown no net decline among plants over 100 years across 16,000 sites examined around the world.)

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"Humans should feel less shame about molding their environment to suit their survival needs. When beavers make a dam, they cause the local extinction of numerous riverine species that cannot survive in the new lake. But that new lake supports a set of species that is just as diverse. Studies have shown that when humans introduce invasive plant species, native diversity sometimes suffers, but productivity — the cycling of nutrients through the ecosystem — frequently increases. Invasives can bring other benefits, too: Plants such as the Phragmites reed have been shown to perform better at reducing coastal erosion and storing carbon than native vegetation in some areas, like the Chesapeake.

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"We should save whatever species and habitats can be easily rescued (once-endangered creatures such as bald eagles and peregrine falcons now flourish), refrain from polluting waterways, limit consumption of fossil fuels and rely more on low-impact renewable-energy sources.

"We should do this to create a stable, equitable future for the coming billions of people, not for the vanishing northern river shark. Conservation is needed for ourselves and only ourselves. All those future people deserve a happy, safe life on an ecologically robust planet, regardless of the state of the natural world compared with its pre-human condition. We cannot thrive without crops or pollinators, or along coastlines as sea levels rise and as storms and flooding intensify.

"Yet that robust planet will still erase huge swaths of animal and plant life. Even if we live as sustainably as we can, many creatures will die off, and alien species will disrupt formerly “pristine” native ecosystems. The sixth extinction is ongoing and inevitable — and Earth’s long-term recovery is guaranteed by history (though the process will be slow). Invasion and extinction are the regenerative and rejuvenating mechanisms of evolution, the engines of biodiversity.

"If this means fewer dazzling species, fewer unspoiled forests, less untamed wilderness, so be it. They will return in time. The Tree of Life will continue branching, even if we prune it back. The question is: How will we live in the meantime?"

Comment: A very wise essay. The bush of life with all its strange extremophiles tells us extinction never stops a diverse group of living organisms.