Extinction: past as key to the present

Nature, 2011

The AAG Review of Books

Molecular Phylogenetics and Evolution, 2007

This paper serves as an introduction to this PNAS supplement, which resulted from the Arthur M. Sackler Colloquium of the National Academy of Sciences, ''In the Light of Evolution II: Biodiversity and Extinction,'' held December 6-8, 2007, at the Arnold and Mabel Beckman Center of the National Academies of Sciences and Engineering in Irvine, CA. It is the second in a series of colloquia under the general title ''In the Light of Evolution'' (see Box 1). The complete program and audio files of most presentations are available on the NAS web site at www.nasonline.org/ Sacklerbiodiversity. Papers from the first colloquium in the series, titled ''In the Light of Evolution I: Adaptation and Complex Design,'' appeared in ref. 1.

Proceedings of the National Academy of Sciences, 2008

Current plant and animal diversity preserves at most 1-2% of the species that have existed over the past 600 million years. But understanding the evolutionary impact of these extinctions requires a variety of metrics. The traditional measurement is loss of taxa (species or a higher category) but in the absence of phylogenetic information it is difficult to distinguish the evolutionary depth of different patterns of extinction: the same species loss can encompass very different losses of evolutionary history. Furthermore, both taxic and phylogenetic measures are poor metrics of morphologic disparity. Other measures of lost diversity include: functional diversity, architectural components, behavioral and social repertoires, and developmental strategies. The canonical five mass extinctions of the Phanerozoic reveals the loss of different, albeit sometimes overlapping, aspects of loss of evolutionary history. The end-Permian mass extinction (252 Ma) reduced all measures of diversity. The same was not true of other episodes, differences that may reflect their duration and structure. The construction of biodiversity reflects similarly uneven contributions to each of these metrics. Unraveling these contributions requires greater attention to feedbacks on biodiversity and the temporal variability in their contribution to evolutionary history. Taxic diversity increases after mass extinctions, but the response by other aspects of evolutionary history is less well studied. Earlier views of postextinction biotic recovery as the refilling of empty ecospace fail to capture the dynamics of this diversity increase.

Evolution on Planet Earth: The impact of the physical …, 2003

In historical sciences such as palaeontology cause and effect must be established by documenting multiple associations of proposed causes and putative effects in the correct logical sequence. Employing this approach the taxonomic extinction record over the last 600 million years, along with a variety of environmental change indices, can be used to identify general extinction causes. The well-established decline in "background" extinction intensity is associated with long-term and progressive changes in a variety of environmental factors. These data suggest that the declining extinction-intensity gradient has been influenced strongly by generalized tectonic and evolutionary-ecological factors whose operation has resulted in: (1) a progressive increase in the organization and intensity of marine circulation, (2) a progressive decrease in the amount of continent-derived phytoplankton-limiting nutrients reaching marine environments, and (3) a progressive increase in the efficiency and recycling rate of marine primary producers. There is also circumstantial evidence that the Earth has experience a first-order trend toward increasing in global average surface temperatures and expansion of tropical habitats over this same time interval. Operation of these factors, in turn, has altered the abiotic and biotic nature of marine habitats with consequent macroevolutionary effects on planktonic and benthic organisms. In addition, a set of relatively shorter-term, tectonically-influenced, environmental perturbations (e.g., rapid sea-level fall, continental flood-basalt volcanism) exhibit consistent associations with stage-level extinction-intensity peaks or "mass extinction" events. Taken as a whole these data suggest that the primary controls on long and intermediate-term taxonomic extinction patterns at all scales are tectonic and likely mediated through the waxing and waning of lineages that occupy the base of marine ecological hierarchies.

Theory and Event, 2021

What is extinction? What is the difference between death and extinction? Between evolution (surviving as other) and extinction (not surviving at all)? This article begins by considering the articulation of extinction in Extinction Studies. Combining rigorous philosophical insights with cutting-edge scientific research, Extinction Studies offers one of the best understandings we have: the extinct is not "what it is" (absolutely gone), but remains (in both senses of the word). The extinct's absence survives, calling to us from beyond the grave. However, I argue almost the exact opposite in this article: extinction is remainderless. And extinction itself is going extinct.

The Extinction Crisis Extinctions are nothing new in nature. Over 98 percent of all species that ever existed on earth are now extinct. Over the past 500 million years, at least five great mass extinctions have occurred. The largest was the end-Permian extinction, which occurred roughly 252 million years ago. Nearly ninety percent of all plant and animal species were wiped out then, probably as a result of rapid global warming. 1 A more famous mass extinction occurred 65 million years ago when the dinosaurs died out, perhaps due to a large asteroid strike that plunged the earth into a prolonged period of darkness and cold. After each mass extinction, it took at least 20 million years for previous levels of biodiversity to be restored. 2 Today we are in the midst of a sixth great extinction-one caused almost entirely by us. Normally in nature, roughly one to five species become extinct each year. Today, dozens, if not hundreds, of species of plants and animals are vanishing every single day. And because of factors such as habitat destruction, climate change, overharvesting, pollution, and invasive species, the extinction crisis is rapidly worsening. According to a recent landmark United Nations report, about a million species are at risk of extinction over the next few decades. 3 Worldwide, humans have wiped out 60% of all mammals, birds, insects, and reptiles since 1970. 4 A quarter of all mammals and a third of all amphibians are now listed as "threatened." In this chapter, we explore why biodiversity matters and how we should respond to the extinction crisis.

2010

Functional Ecology, 2017

Responses to technical innovations are varied, with some people engaging early with new technology and pushing the envelope to see what could be achieved, whereas others push back against change. Then there are those who are most interested in the implications of a new way of doing something. Often the reality of a technical advance means users are obliged to adjust; for example, to electronic money transfer (Freedman 2000). Sometimes, the mere promise or potential of something revolutionary is enough to force a reaction, for example, cold fusion (Close 1991). De-extinction, the resurrection of extinct species, sits in this second category. Not so much a single technical advance (though the new gene-editing tool CRISPR will be transformative), as a coming together of developing techniques that make a new application possibleand it is possible, make no mistake. The next decade will see the cloning or genetic reconstruction of some version of a formerly extinct species; one that will live long enough to breathe and shake its fur, feathers, or scales, or to unfurl a leaf. The technical challenges that remain are formidable, but so very much has already been achieved along the de-extinction pathway. I'm often asked, 'Is this really possible?' My answer is yesde-extinction has moved from science fiction to science feasibility-and I point to the case of the successful cloning using tissue from the extinct Pyrenean ibex and a hybrid goat as a gestational surrogate (Folch et al. 2009). It was only 6 years ago that a New Zealand politician was mocked by his Parliamentary colleagues for mooting the idea of de-extincting (we still need to get the verb right) the moa (Smith 2014). Since then some serious and seriously smart people have been working towards resurrecting (a better word) the moa, the passenger pigeon, even the woolly mammoth. The prospect of de-extinction has stimulated the public debate and galvanized the media. True, they have to get past the obsession with mammoths, but at least, it is widely understood that dinosaurs are not on any de-extinction candidate lists. Much of the general discussion has dealt with ethical issues, revisiting the genetically modified organism (GMO) debate and questioning the hubris of 'playing God', our duty to right past wrongs, and the moral hazards of changing the public perceptions of the finality of species extinction (Sandler 2013). On the other side, much of the technical material concerns how de-extinction might be achieved, and there are many who

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