Category: Uncategorized

SELF-EMOLIATION. "In vertebrates, for example, the high levels of free corticosteroids that trigger rapid senescence and death also allow tissue protein to be consumed as an energy source during a brief and intensely competitive breeding season." https://lnkd.in/ecP3KMX View in LinkedIn

BODY PLAN DIVERSITY. “The Cambrian explosion is named for the geologically sudden appearance of numerous metazoan body plans (many of living phyla) between about 530 and 520 million years ago, only 1.7% of the duration of the fossil record of animals.” https://lnkd.in/eagvRCB View in LinkedIn

FUNCTION OF EARLY DEATH. "In many semelparous organisms, the adaptive function of the nominal ‘death program’ is apparently to increase reproduction, with organismal death resulting as an incidental side-effect (making organismal senescence an example of “by-product death”." https://lnkd.in/ecP3KMX View in LinkedIn

“THE ENIGMA that is the Cambrian Explosion is one of the most perplexing, fascinating, and important events in the evolution of life on Earth. Enigmatic due to the lack of evidence, and that which we do have is not necessarily clear in its implications producing an array of varying views, and hypotheses.” https://lnkd.in/ex6BW5w View in LinkedIn

SOMETIMES PROGRAMMED. "There is substantial evidence for genetic control of senescence in some iteroparous animals, indicating that senescence is at least sometimes “programmed” (in the inclusive sense) and highlighting the question of the relationship between aging “programs” and selection." https://lnkd.in/ecP3KMX View in LinkedIn

NOT PROGRAMMED. "General explanations for organismal senescence are varied and contentious, and the idea that iteroparous senescence is “programmed” is not the majority view." https://lnkd.in/ecP3KMX View in LinkedIn

SO ENDS this topic of mass extinctions. It is a remarkable history of boom and bust events in life’s history, from great abundance to hanging by a thread. What is evident, is that it is hard to snuff life out, even in the face of cataclysmic events. Some life forms will survive. Even when you look at the growth and survival of seedlings, there is an evident force to survive at all costs in any conditions. Life is a fiercely determined force. View in LinkedIn

COMPLEX AND UNPREDICTABLE. “The evolutionary response to mass extinction is slow on human time scales, difficult to predict owing to the contingencies of postextinction conditions including the identity and evolutionary dynamics of the survivors, and geographically heterogeneous.” http://www.pnas.org/content/98/10/5393.full/Donnie) View in LinkedIn

FORCE OF CHANGE. “Extinction itself promotes biotic interchange. Asymmetries in ancient biotic interchange generally appear to reflect geographic differences in extinction intensity. The end-Cretaceous extinction shows, however, that although biotic interchanges pervade the postextinction world, simple linear relationships can break down to produce unexpected source-sink patterns.“ http://www.pnas.org/content/98/10/5393.full/Donnie) View in LinkedIn

NO GUARANTEES. “Survivorship during mass extinctions need not be closely related to many aspects of biological success as measured during “background” times.” http://www.pnas.org/content/98/10/5393.full/Donnie) View in LinkedIn