Microevolution to Macroevolution

Phyletic Gradualism

Punctuated Equilibrium

https://en.wikipedia.org/wiki/Generation

"Everyone who believes in slow and gradual evolution, will of course admit that specific changes may have been as abrupt and as great as any single variation which we meet with under nature, or even under domestication. But as species are more variable when domesticated or cultivated than under their natural conditions, it is not probable that such great and abrupt variations have often occurred under nature, as are known occasionally to arise under domestication."

...

"Although very many species have almost certainly been produced by steps not greater than those separating fine varieties; yet it may be maintained that some have been developed in a different and abrupt manner. ... One class of facts, however, namely, the sudden appearance of new and distinct forms of life in our geological formations supports at first sight the belief in abrupt development. But the value of this evidence depends entirely on the perfection of the geological record, in relation to periods remote in the history of the world. If the record is as fragmentary as many geologists strenuously assert, there is nothing strange in new forms appearing as if suddenly developed.

Charles Darwin

The Origin of Species

Sixth Edition (1872)

"Paleontology's view of speciation has been dominated by the picture of "phyletic gradualism." It holds that new species arise from the slow and steady transoformation of entire populations. Under its influence, we seek unbroken fossil series linking two forms by insensible gradation as the only complete mirror of Darwininan processes; we ascribe all breaks to imperfections in the record.

"The theory of allopatric (or geographic) speciation suggests a different interpretation of paleotological data. If new species arise very rapidly in small, peripherally isolated local populations, then the great expectation of insensibly graded fossil sequences is a chimera. A new species does not evolve in the area of its ancestors; it does not arise from the slow transformation of all its forbears. Many breaks in the fossil record are real.

"The history of life is more adequately represented by a picture of "punctuated equilibria" than by the notion of phyletic gradualism. The history of evolution is not one of stately unfolding, but a story of homeostatic equilibria, disturbed only "rarely" (i.e., rather often in the fullness of time) by rapid and episodic events of speciation."

Niles Eldredge & Stephen Jay Gould

"Punctuated Equilibria: An Alternative to Phyletic Gradualism" (1972)

https://en.wikipedia.org/wiki/Population

https://en.wikipedia.org/wiki/Species

https://en.wikipedia.org/wiki/Extinction

https://en.wikipedia.org/wiki/Allopatric_speciation

https://en.wikipedia.org/wiki/Cladogenesis

https://en.wikipedia.org/wiki/Phylogenetic_tree

https://en.wikipedia.org/wiki/Punctuated_equilibrium

https://en.wikipedia.org/wiki/Sympatric_speciation

https://en.wikipedia.org/wiki/Fixation_(population_genetics)

https://en.wikipedia.org/wiki/Population_bottleneck

https://en.wikipedia.org/wiki/Genetic_drift

https://en.wikipedia.org/wiki/Lineage_(evolution)

https://en.wikipedia.org/wiki/Reproductive_isolation#Behavioral_isolation

https://en.wikipedia.org/wiki/Batesian_mimicry

https://en.wikipedia.org/wiki/Anagenesis

https://en.wikipedia.org/wiki/Adaptation

https://en.wikipedia.org/wiki/Reproductive_isolation

https://en.wikipedia.org/wiki/Phyletic_gradualism

Imagine that a series of mudslides consistently occurs over several decades.

Common Misconceptions

"No New Discovery"

Darwin was an incrementalist, not a strict gradualist.

"...the periods during which species have undergone modification, though long as measured in years, have probably been short in comparison with the periods during which they retain the same form."

Charles Darwin,

The Origin of Species

Fifth Edition (1869)

Transitional fossil forms still exist.

"We claimed no new discovery, but only a novel interpretation for the oldest and most robust of palaeontological observations: the geologically instantaneous origination and subsequent stability (often for millions of years) of palaeontological 'morphospecies'. This observation had long been ascribed, by Darwin and others, to the notorious imperfection of the fossil record, and was therefore read in a negative light--as missing information about evolution..."

...

"In a strictly logical sense, this negative explanation worked and preserved gradualism, then falsely equated with evolution itself, amidst an astonishing lack of evidence for this putative main signal of Darwinism."

...

"We realized that a standard biological account...speciation in small populations peripherally isolated from a parental stock, would yield stasis and punctuation when properly scaled into the vastness of geological time--for small populations speciating away from a central mass in tens or hundreds of thousands of years, will translate in almost every geological circumstance as a punctuation on a bedding plane, not gradual change up a hill of sediment, whereas stasis should characterize the long and recoverable history of successful central populations."

Niles Eldredge & Stephen Jay Gould,

Punctuated Equilibrium Comes of Age (1993)

"We proposed the theory of punctuated equilibrium largely to provide a different explanation for pervasive trends in the fossil record. Trends, we argued, cannot be attributed to gradual transformation within lineages, but must arise from the differential success of certain kind of species. A trend, we argued, is more like climbing a flight of stairs (punctuations and stasis) than rolling up an inclined plane.

"Since we proposed punctuated equilibria to explain trends, it is infuriating to be quoted again and again by creationists—whether through design or stupidity, I do not know—as admitting that the fossil record includes no transitional forms. Transitional forms are generally lacking at the species level, but they are abundant between larger groups."

Stephen Jay Gould,

Evolution as Fact and Theory (1994)

https://en.wikipedia.org/wiki/Tree_of_life_(biology)