Quiz & Worksheet - Punctuated Equilibrium Theory | …
Ensure your understanding of the punctuated equilibrium theory by taking an interactive quiz
Gradual Change Vs. Punctuated Equilibrium : The …
In summary, today’s orthodox late-Proterozoic hypothesis is that the complex dynamics of a supercontinent breakup somehow triggered . The global glaciation was reversed by runaway effects primarily related to an immense increase in atmospheric carbon dioxide. During the events, oceanic life would have been delivered vast amounts of continental nutrients scoured from the rocks by glaciers, and the hot conditions would have combined to create a global explosion of photosynthetic life. A billion years of relative equilibrium between prokaryotes and eukaryotes was ultimately shattered, and oxygen levels began rising during the Cryogenian and Ediacaran periods toward modern levels. Largely sterilized oceans, which began to be oxygenated at depth for the first time, are now thought to have prepared the way for what came next: the rise of complex life.
When scientists and scholars discuss , or the demise of , or the , some will always attribute such events to climate change as they deflect responsibility from humans. Climate change has probably never been the ultimate cause for such events. The ultimate cause was probably always humans, and everything else was a proximate cause, at most. In the past several hundred years, there are clear instances when deforestation and sheep grazing quickly turned moist forests and/or , particularly in the kinds of temperate regions where the first civilizations arose. When scientists have investigated and reconstructed the dynamics that led to the collapse of , the , or the Anasazi, the story was always the same. Human civilizations altered the ecosystems, usually via deforestation and agriculture, which made them lose their resilience, and a drought did them in. Those urban areas were permanently abandoned. That civilization-collapse dynamic is like the hypothesis for why mass extinctions have punctuated the eon of complex life: those multi-tiered energy systems .
Punctuated Equilibrium Theory in IS Research | …
Finally, this pattern of long stasis, with change concentratedin rapid episodes that establish new equilibria, may be quite general atseveral scales of time and magnitude, forming a kind of fractal patternin self-similarity. According to the punctuated equilibrium model of speciation,trends within lineages occur by accumulated episodes of geologically instantaneousspeciation, rather than by gradual change within continuous populations(like climbing a staircase rather than rolling a ball up an inclined plane).
CSCW is one example; other fields and regions might be similarly reassessed. Punctuated equilibrium is found in nature. Pressure on tectonic plates builds steadily beneath the Earth’s crust, but instead of gradual change at the surface, earthquakes punctuate periods of equilibrium. It could help explain why so often organizations and entire industries are caught flat-footed by waves of technology change. Explorations of history can reveal the power of unseen forces to shape events. To influence where we go, we must understand the waves we surf.
Gradual Change Vs. Punctuated Equilibrium : The Study …
Charles believed that . He did not believe this process to be "perfectly smooth," but rather, "stepwise," with a species evolving and accumulating small variations over long periods of time. Darwin assumed that if evolution is gradual then there should be a record in fossils of small incremental change within a species. But in many cases, Darwin, and scientists today, are unable to find most of these intermediate forms. Darwin blamed lack of transitional forms on gaps in the fossil record, a good assertion, because the chances of each of those critical changing forms having been preserved as fossils are very small. However in 1972, evolutionary scientists Stephen Jay Gould and Niles Eldredge proposed another explanation for the numerous gaps in the fossil record.
Further complicating things is that existing theories can generate new hypotheses. Punctuated equilibrium, for example, is a hypothesis that predicts periods of rapid evolutionary change followed by periods of relative stasis. When proposed by , it was a new hypothesis, but the hypothesis was spawned from existing evolutionary theory. But wait! Isn’t the theory of natural selection part of evolutionary theory? Can a theory be a subset of a theory? Sure. Like I said, it’s all a bit arbitrary. Evolutionary theory is a big, lovely, over-arching golf umbrella of a theory.
phyletic gradualism and punctuated equilibrium Science 101 IP ..
Hardy-Weinberg - Kansas State University
Define Punctuated Equilibrium
Macroevolution: Its definition, Philosophy and History
Answer to What main problem with Darwin's hypothesis did punctuated equilibrium attempt to solve?
It is a challenge for scientists and philosophers to define life
Pearson - The Biology Place
This is partially because life is a process, not a substance
Punctuated equilibrium is the theory that animal and plant species exhibit periods of evolutionary stasis interrupted by short periods of rapid evolutionary change. The fossil record shows little change for a long time, then a dramatic shift. Is the record deceptive? Could the species have gradually evolved elsewhere and migrated to the location? If the theory is correct, what is the mechanism? Do mutations accumulate until they collectively provide a significant selective advantage? Does a sudden change in climate or environment enable a new configuration of characteristics to thrive? The fossil record is inconclusive.
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