Return to David's theory of evolution (Evolution)

by David Turell , Friday, August 26, 2022, 05:50 (818 days ago) @ David Turell

dhw makes slight of the necessary food supply in His constant illogical complaint. God knew the burgeoning human population had to have enough food. Look at this new analysis of our new food supply crisis:

Another article damaging his thinking:

https://www.sciencemagazinedigital.org/sciencemagazine/library/item/26_august_2022/4036...

"Food webs influence ecosystem diversity and functioning. Contemporary defaunation has reduced food web complexity, but simplification caused by past defaunation is difficult to reconstruct given the sparse paleorecord of predator-prey interactions. We identified changes to terrestrial mammal food webs globally over the past ∼130,000 years using extinct and extant mammal traits, geographic ranges, observed predator-prey interactions, and deep learning models. Food webs underwent steep regional declines in complexity through loss of food web links after the arrival and expansion of human populations. We estimate that defaunation has caused a 53% decline in food web links globally. Although extinctions explain much of this effect, range losses for extant species degraded food webs to a similar extent, highlighting the potential for food web restoration via extant species recovery.

"Human activities have caused global extinction or local extirpation of many animal species. Habitat loss, direct exploitation, invasive species, and other global change drivers have contributed to recent defaunation, which in turn has caused cascading impacts on biodiversity and ecosystem functioning through disruption of food webs. Yet defaunation, and the potential for food web disruption, is not only a contemporary phenomenon. Declines in species diversity since the last interglacial period (∼130,000 years ago) are well known for groups such as terrestrial mammals. Although there are persistent discussions on the relative roles of humans, climate, and their interactions as drivers of these extinctions, the spatiotemporal pattern of declines strongly suggests a major human rol. The past, and ongoing, selective loss of large-bodied mammals has caused a marked downsizing of mammal assemblages relative to the preceding 30 million years

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"Our reconstruction of terrestrial mammal food webs allowed us to estimate the global magnitude of mammal food web collapse since the Late Pleistocene. We found that although only ∼6% of terrestrial mammal species have gone extinct since the Late Pleistocene, more than half of mammal food web links have disappeared. Although much of the global food web simplification has resulted from extinctions that occurred centuries to millennia ago, range contractions in surviving species explain a similar magnitude of simplification. Controlled and natural experiments show that food web complexity supports ecosystem resilience and functioning, and ecological network simplification reduces ecosystem functioning (36). We found that the species most affected by defaunation are among the strongest contributors to food web complexity."

Comment: Same old story. All of the giant bush of evolution is a food supply for the huge human population. And all we do is unthinkingly damage it. And dhw distorts the importance of it.