Wielkie wymierania, strategie przeżycia i odradzania się biocenoz z globalnych kryzysów - aktualny stan poznania
Abstract
W fanerozoicznej historii Ziemi miało miejsce 7 epizodów wielkich wymierań. Typową sekwencję zdarzeń w procesie masowego wymierania zapoczątkowuje faza wymierania, po której następuje faza przetrwania, a następnie przychodzi faza odrodzenia. W oparciu o szczegółowe dane stratygraficzne, geochemiczne i paleontologiczne z wielu wielkich wymierań sporządzono model przetrwania, odradzania się i radiacji biocenoz z tych kryzysów (Harries & Kauffman, 1980, 1996). Taksony, które przetrwały kryzys środowiskowy, reprezentowane są przez gatunki, które stosowały różne strategie ekologiczne i biologiczne. Stwierdzono 16 potencjalnych mechanizmów lub strategii przetrwania; większość z nich jest powszechnie stosowana przez organizmy w normalnych warunkach środowiskowych. Można je zaliczyć do 6 szerszych grup obejmujących mechanizmy ewolucyjne, środowiskowe, związane z przystosowaniami żywieniowymi i życiowymi, dynamikę populacyjną, fizjologiczne i reprodukcyjne (Harrries i in., 1996).
MASS EXTINCTIONS AND MECHANISM OF SURVIVAL AND RECOVERY FROM GLOBAL CRISES: AN OVERVIEW
Summary
Seven major episodes of biological extinction in Phanerozoic history have been identified as times of mass extinctions. The typical sequence of events in a mass extinction is initiated by an extinction phase, during which diversity falls rapidly, followed by a survival phase of minimal diversity and then a recovery phase of rapid diversity increase. High-resolution stratigraphic, geochemical and paleontological data of several mass extinction intervals gave rise to a model for survival and recovery from mass extinctions in which the successful survival mechanisms are grouped into a series of characteristic stratigraphic patterns (Harries & Kauffman, 1980, 1996). It also turned out that the repopulation of the global ecosystem took place among ecologically and genetically diverse and complex taxa.
There are a number of potential adaptative traits by which some populations survived the rapid, large-scale environmental and ecological perturbations commonly associated with mass extinction intervals. Many of these are common traits operative during background
conditions. These mechanisms can be subdivided into six primary groups: evolutionary, habitat, trophic/life habit, population dynamics, physiological and reproductive (Harrries et al., 1996).
MASS EXTINCTIONS AND MECHANISM OF SURVIVAL AND RECOVERY FROM GLOBAL CRISES: AN OVERVIEW
Summary
Seven major episodes of biological extinction in Phanerozoic history have been identified as times of mass extinctions. The typical sequence of events in a mass extinction is initiated by an extinction phase, during which diversity falls rapidly, followed by a survival phase of minimal diversity and then a recovery phase of rapid diversity increase. High-resolution stratigraphic, geochemical and paleontological data of several mass extinction intervals gave rise to a model for survival and recovery from mass extinctions in which the successful survival mechanisms are grouped into a series of characteristic stratigraphic patterns (Harries & Kauffman, 1980, 1996). It also turned out that the repopulation of the global ecosystem took place among ecologically and genetically diverse and complex taxa.
There are a number of potential adaptative traits by which some populations survived the rapid, large-scale environmental and ecological perturbations commonly associated with mass extinction intervals. Many of these are common traits operative during background
conditions. These mechanisms can be subdivided into six primary groups: evolutionary, habitat, trophic/life habit, population dynamics, physiological and reproductive (Harrries et al., 1996).