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Paleontologists have identified five strata in the fossil record that appear to show sudden and dramatic (greater than half of all extant species disappearing from the fossil record) losses in biodiversity. These are called mass extinctions.
- Punctuated Equilibrium Explained
- Punctuated Equilibrium Examples
- Features of Punctuated Equilibrium
- Gradualism vs Punctuated Equilibrium
So, if a species appears in fossil records for about 10 million years, it is likely that speciation occurred over the span of fewer than 100,000 years. Once complete, however, the model suggests that there is little morphological change after the speciation event. The species will then maintain a period of stability, called stasis, for a long perio...
Support for punctuated equilibrium is seen in fossil records. The impact of reproductive isolation has been observed by biologists, systematists, and taxonomists across the world. Given the fact that this is a theory of evolution, its predictions cannot be directly tested. While the fossil recordcan provide support for the theory, some indications ...
One of the cornerstones of this hypothesis is that reproductive isolation is necessary for the formation of new species. This implies that the fossil record at any one place is unlikely to record the process of speciation because new species can evolve only from small, isolated populations. Therefore, variationswill be seen only in fossils of the s...
Punctuated equilibrium is pitted against phyletic gradualism. These competing theories of evolution both hypothesize about the rate of emergence of new species.Gradualism places importance on the slow appearance of new characters in interbreeding subspecies that, over time, lead to the evolution of a new species from ancestral forms. Fossils seem t...
- Gabe Buckley
Eldredge and Gould characterized their model as punctuated equilibria. "Punctuated" referred to the sudden appearance of morphologically distinct new species in the fossil record. "Equilibria" referred to the stasis that species exhibit following speciation.
