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BURSTS OF INNOVATION. “Attempts to predict evolutionary behavior after major extinction events can only operate in broad generalities, and always with the caveat, “expect the unexpected.” http://www.pnas.org/content/98/10/5393.full/Donnie) View in LinkedIn

NOT BUSINESS AS USUAL. “Although the evolutionary response to mass extinction has sometimes been depicted simply in terms of the reoccupation of preextinction adaptive peaks (“reinventing the ecological wheel), evolution is both too opportunistic and too constrained by inherited body plans for this to be wholly true.” http://www.pnas.org/content/98/10/5393.full/Donnie) View in LinkedIn

EXUBERANT RADIATION. “Postextinction bursts of diversification have been extensively discussed and documented for many extinction events, both morphologically and at several taxonomic levels.” http://www.pnas.org/content/98/10/5393.full/Donnie) View in LinkedIn

FRAGMENT FROM NATURE continues from last weekend on the theme of mass extinctions, and how life on this planet has teetered between explosive diversity and near extinction five times in its short history. Despite these near fatal wipeout situations, enough individuals survive to repopulate the world. But, curiously, after the great Cambian explosion of diversity, no new phyla have evolved. View in LinkedIn

ITEROPAROUS ORGANISMS "have multiple reproductive episodes during the life cycle, as opposed to a solitary event. In these species, senescence leading to death is less abrupt and dramatic, but is ubiquitous nonetheless. Although data are difficult to collect, a high rate of death due to senescence in iteroparous species has been documented for some species even in the wild." https://lnkd.in/ecP3KMX View in LinkedIn

HOLIN-ANTIHOLIN SYSTEMS. "A similar puzzle arises in the case of holin-antiholin systems, which are encoded by bacteriophages and control the timing of host cell lysis and the dispersal of virions. Chromosomally-encoded homologs are biochemically distinct from toxin-antitoxin systems, but also result in cell death." https://lnkd.in/ecP3KMX View in LinkedIn

TOXIN-ANTITOXIN SYSTEMS. "In prokaryotes, conjugative plasmids often encode for the simultaneous production of long-lived toxins and short-lived antitoxins. When these are present together, the toxin is harmless to the host. However, if one daughter cell is cured of the plasmid, it will inherit toxic cytoplasm without a source of antitoxin and will die." Train driver’s Dead Man’s Switch. https://lnkd.in/ecP3KMX View in LinkedIn

TRANSPOSONS KILLING THE HOST. "This process may be associated with occurrence of new mutations in the transferred genes and their improved ability to survive in the new host. This mechanism has been suggested to occur in S. cerevisiae although the author allows that, “this hypothesis lacks direct experimental support”. https://lnkd.in/ecP3KMX View in LinkedIn

MOBILE ELEMENTS. "Genetic elements have been closely studied that routinely increase their inclusive fitness by killing their host. In some cases, this peculiar form of selection may explain the function and evolution of genes for unicell programmed organismal death When a cell has low chances for reproduction, programmed organismal death and the transfer of genes from the dying cell to a new host can save the genes." https://lnkd.in/ecP3KMX View in LinkedIn

COMPETING INTERESTS. "The reproductive interests of genetic elements can differ from those of the organism carrying them. It is well established that gene-level selection can generate traits that are detrimental to individual fitness, while benefitting smaller genetic entities within them." https://lnkd.in/ecP3KMX View in LinkedIn