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Differences between Gradualism and Uniformitarianism


From what I understand, gradualism is the idea that small changes affect species over time. Uniformitarianism argues that the same processes that occurred in the past are the same as those in the present.

Does gradualism state that these small changes are constant over time? In that case, it isn't much different from uniformitarianism.

I'm thinking that the difference that uniformitarianism allows for catastrophes and supports Aristotle's scala naturae, while gradualism makes a point for evolution due to its theory of slow processes.


Gradualism is the view that large-scale changes occurs by the accumulated effects of small changes over long periods of time, rather than by rare cataclysmic events of massive effect.

Uniformitarianism is the view that the same forces that shaped the world in the past continue to operate today. Historically, uniformitarianism has often included aspects of gradualism (i.e. definitions by Lyell), e.g. by assuming uniformity of rates. Uniformitarianism was also originally proposed as the opposite of Catastrophism. However, in modern use, the focus lies on uniformity of processes, and rapid catastrophic changes are allowed under uniformitarianism. Also note that the term Actualism is sometimes used for modern interpretations of uniformitarianism.

If we posited that early evolution occurred by small Lamarckian changes and current evolution occurs by small Darwinian changes, we have a model that is gradualist but not uniformitarian.

If we posited that the earth's topography was formed by meteor impacts and massive tsunamis, in sharp sudden strokes of massive effect, but acknowledged that these same processes occur today, we would have a theory that is uniformitarian but not gradualist.

(I don't understand what you are asking in your last paragraph, or how this relates to your main question.)


Difference Between Uniformitarianism and Catastrophism

The key difference between uniformitarianism and catastrophism is the manner in which they explain the changes in the Earth’s crust during geological history. Uniformitarianism states that the changes in the Earth’s crust are a result of the action of continuous and uniform processes, while catastrophism states the changes in the Earth’s crust are mainly a result of sudden violent and unusual events.

Uniformitarianism and Catastrophism are two geographical theories developed regarding Earth’s geological features. Uniformitarianism proposes that the geological features of Earth were created in slow incremental changes such as erosion. In contrast, catastrophism suggests the Earth has largely been shaped by sudden, short-lived, violent events.

CONTENTS


Uniformitarianism

This is a diagram depicting the rock forming processes described by uniformitarianism.

Uniformitarianism is a theory based on the work of James Hutton and made popular by Charles Lyell in the 19 th century. This theory states that the forces and processes observable at earth’s surface are the same that have shaped earth’s landscape throughout natural history.

The earth sculpting processes alluded to above are the processes of erosion, deposition, compaction and uplift. Although these processes are constant, they occur at extremely slow rates. As a farmer, Hutton realized that the rates of erosion were so slow that it would take an inconceivable amount of time to observe drastic changes in Earth’s landscape.

The theory also states that these processes have occurred at constant rates throughout natural history. James Hutton explains this idea in his book entitled Theory of the Earth, “… we find no vestige of a beginning – no prospect of an end.” Hutton was the first scientist to conclude that the age of the Earth must be so incredibly old that the mind can’t begin to estimate its length.

Lyell even went to the Paris Basin to observe the rocks responsible for catastrophism, a theory in direct opposition with uniformitarianism. Based on catastrophism, the forces shaping the earth are not constant. However, when Lyell observed the mass extinction events in the fossil succession of the Paris Basin, he drew a very different conclusion. Lyell recognized that cyclical depositional environments and reoccurring extinctions show that there are controls that cause these processes to be recurrent. However, Lyell saw these processes as taking place over vast amounts of time and only appearing to be abrupt because of the scale of time preserved in the rocks.

Lyell’s theory of uniformitarianism would eventually coincide with plutonism as the foundation of modern geology. Uniformitarianism is also the first theory to predict deep time in western science. Deep time is the idea that Earth history is so deep that a person can’t possibly conceive the amount of time that has passed on planet earth. This further proved that the earth could not be a few thousand years old, as believed by theologian scientists.


Characteristics of Ecological Network Dynamics

15.3 Punctuated Dynamics

As noted in Chapter 13 , geologist/anthropologist Charles Lyell formulated, in the nineteenth century, the philosophy of uniformitarianism or gradualism , which claimed that smooth gradual processes were at work in natural systems. A small cause yielded a small effect. All things could be explained by linear extrapolation. Darwin apparently accepted this view, at least initially, and stated that evolution is smooth and gradual. Much later, Gould and Eldredge disputed the gradualism view and instead offered a “punctuated equilibrium” explanation (e.g., in their classic 1977 paper 4 ). “Punctuated equilibrium is the idea that evolution occurs in spurts instead of following the slow, but steady path that Darwin suggested. Long periods of stasis with little activity in terms of extinctions or emergence of new species are interrupted by intermittent bursts of activity.” 5

My view is that punctuated dynamics, both in long developmental time frames and in short operational time frames, are at work in ecological systems. I claim that the dynamics of complex ecological networks exhibit such behavior. The time series of ecological system events are punctuated and the event probability distribution follows a power law. There is a wide distribution of events, from the ordinary (gradual and expected) to the extreme (abrupt and unexpected).

Figure 15.1 , which illustrates ecological network operation, displays two different moderate-sized propagation events that occur at two different instants of time. Events of all sizes, however, can occur. Smaller events involving just a few nodes are most likely, but extreme events involving nearly all nodes in the network can also occur.

15.3.1 Black Swans

“Black swans” are extreme events—unlikely, unexpected, high-impact events. They reside at the “long tails” of power-law/fractal event distributions. The black swan metaphor, perhaps mentioned first in John Stuart Mill, A System of Logic (1860), has been used many times since. Currently, it is often associated with Karl Popper and his work on the problem of induction: I see only white swans therefore all swans are white except when they are not, etc. (The Problem of Induction was perhaps first addressed by David Hume in the eighteenth century.)

A pictorial illustration of the black swan region of a power-law event distribution is provided in Figure 15.2 . The flat portion of the curve on the left (expected events) side of the diagram is in the so-called cutoff region of the distribution, where the power law does not apply.

Figure 15.2 . Black swan region.

Marsh and Pfleiderer (2012) discuss the impacts of black swan extreme events on the financial markets and the Standard & Poor’s (S&P) 500 Index. They note that many existing financial models use simple, unconditional Gaussian assumptions that ignore or otherwise minimize extreme events. As a result, these models are subject to serious failures. Marsh and Pfleiderer go on to describe modeling methods that may deal more effectively with extreme events. As part of their analysis, they provide a plot of maximum drawdown (over intervals of 24 months) on the S&P 500 Index. Maximum drawdown is a percentage measure of the decline of a variable from a previous peak. Their plot very well illustrates financial market dynamics and the presence of black swan events. An adaptation of the Marsh and Pfleiderer plot is provided here as Figure 15.3 .

Figure 15.3 . Black swans in the stock market.

(Adapted, with permission, from &quotBlack Swans&quot and the Financial Crisis, T. Marsh and P. Pfleiderer, Review of Pacific Basin Financial Markets and Policies, Volume 15, Issue Number 02 Copyright © 2012 World Scientific Publishing).

The figure covers the time period from 1801 to beyond 2008. Although S&P 500 history dates back only to 1923, Marsh and Pfleiderer have extended the chart back to 1801 using data from the Global Financial Database.

The time series plot of Figure 15.3 shows a wide range of fluctuating event sizes. There are a few extremely large events. The reference line on the figure is the drawdown of 50.95% that occurred during the financial crisis of 2008. Events of 2008-magnitude have occurred three times in 211 years. There is also a considerable number of medium-size to large-size events, but most events are small. The event dynamics are clearly punctuated. This behavior is consistent with the black swan power-law probability distribution of Figure 15.2 .

Nassim Taleb (2007) emphasizes that large, extreme, high-impact black swan events are not anomalies. They are a very important part of system behavior, and can change the playing field. Taleb states, “By removing the ten biggest one-day moves from the U.S. stock market over the past fifty years, we see a huge difference in returns—and yet conventional finance sees these one-day jumps as mere anomalies. … In the last fifty years, the ten most extreme days in the financial markets represent half the returns. Ten days in fifty years.”


Uniformitarianism

The principle of uniformitarianism says that the present is the key to the past. This principle has had a profound impact on the science of geology.

James Hutton

Along with Charles Lyell, James Hutton developed the concept of uniformitarianism. He believed Earth's landscapes like mountains and oceans formed over long period of time through gradual processes.

Photograph by SSPL/Getty Images mezzotint by J.R. Smith original by R. Cosway

Have you seen a news clip or a video showing a volcano erupting, or an earthquake shaking a city? One of the interesting things about those events is that they occur today in the same way that they have in the past. Scientists look at modern-day geologic events&mdashwhether as sudden as an earthquake or as slow as the erosion of a river valley&mdashto get a window into past events. This is known as uniformitarianism: the idea that Earth has always changed in uniform ways and that the present is the key to the past.

The principle of uniformitarianism is essential to understanding Earth&rsquos history. However, prior to 1830, uniformitarianism was not the prevailing theory. Until that time, scientists subscribed to the idea of catastrophism. Catastrophism suggested the features seen on the surface of Earth, such as mountains, were formed by large, abrupt changes&mdashor catastrophes. When discussing past climates, opponents to uniformitarianism may speak of no-analog changes. This idea suggests that certain communities or conditions that existed in the past may not be found on Earth today.

The idea of catastrophism was eventually challenged based on the observations and studies of two men&mdashJames Hutton and Charles Lyell. Hutton (1726&ndash1797) was a Scottish farmer and naturalist. In his observations of the world around him, he became convinced natural processes, such as mountain building and erosion, occurred slowly over time through geologic forces that have been at work since Earth first formed. He eventually turned his observations and ideas into what became known as the Principle of Uniformitarianism.

Among the scientists who agreed with Hutton was Charles Lyell. Lyell (1797&ndash1875) was a Scottish geologist. In 1830, he published a book, Principles of Geology, that challenged the idea of catastrophism, which was still the dominant theory despite Hutton&rsquos work. Lyell believed Hutton was correct about the gradually changing processes shaping Earth&rsquos surface. He found his own examples of these processes in his examination of rocks and sediments. For example, he discovered evidence that sea levels had risen and fallen in the past, that volcanoes may exist atop older rocks, and that valleys form slowly by the erosional power of water. The combined efforts of Lyell and Hutton became the foundation of modern geology.

Charles Darwin, the founder of evolutionary biology, looked at uniformitarianism as support for his theory of how new species emerge. The evolution of life, he realized, required vast amounts of time, and the science of geology now showed Earth was extremely old. If there had been plenty of time for mountains to rise up and erode away, then there had also been enough time for millions of species to emerge, and either evolve into new species or go extinct. Science&rsquos conceptions of both geology and biology had entered a new day.

Along with Charles Lyell, James Hutton developed the concept of uniformitarianism. He believed Earth's landscapes like mountains and oceans formed over long period of time through gradual processes.


What are examples of Uniformitarianism?

Keeping this in consideration, what is the concept of Uniformitarianism?

Uniformitarianism - "The Present is the Key to the Past" Uniformitarianism is a geological doctrine. It states that current geologic processes, occurring at the same rates observed today, in the same manner, account for all of Earth's geological features.

  1. All were rooted in uniformitarianism, as the idea was known.
  2. As a geologist, Van Breda was a follower of uniformitarianism.
  3. Through his friend and mentor, the uniformitarianism until 1795.
  4. Certainly evolution, ( and uniformitarianism ) is a theory.

Similarly, what is an example of catastrophism?

Catastrophism. For example, a catastrophist might conclude that the Rocky Mountains were created in a single rapid event such as a great earthquake rather than by imperceptibly slow uplift and erosion. Catastrophism developed in the seventeenth and eighteenth centuries.

What is the difference between catastrophism and Uniformitarianism?

Both theories acknowledge that the Earth's landscape was formed and shaped by natural events over geologic time. While catastrophism assumes that these were violent, short-lived, large-scale events, uniformitarianism supports the idea of gradual, long-lived, small-scale events.


In the natural sciences, gradualism is the theory which holds that profound change is the cumulative product of slow but continuous processes, often contrasted with catastrophism. The theory was proposed in 1795 by James Hutton, a Scottish geologist, and was later incorporated into Charles Lyell’s theory of uniformitarianism. Tenets from both theories were applied to biology and formed the basis of early evolutionary theory.

Charles Darwin was influenced by Lyell’s Principles of Geology, which explained both uniformitarian methodology and theory. Using uniformitarianism, which states that one cannot make an appeal to any force or phenomenon which cannot presently be observed (see catastrophism), Darwin theorized that the evolutionary process must occur gradually, not in saltations, since saltations are not presently observed, and extreme deviations from the usual phenotypic variation would be more likely to be selected against.

Gradualism is often confused with the concept of phyletic gradualism. It is a term coined by Stephen Jay Gould and Niles Eldredge to contrast with their model of punctuated equilibrium, which is gradualist itself, but argues that most evolution is marked by long periods of evolutionary stability (called stasis), which is punctuated by rare instances of branching evolution. [2]

Phyletic gradualism

Phyletic gradualism is a model of evolution which theorizes that most speciation is slow, uniform and gradual. [3] When evolution occurs in this mode, it is usually by the steady transformation of a whole species into a new one (through a process called anagenesis). In this view no clear line of demarcation exists between an ancestral species and a descendant species, unless splitting occurs.

Punctuated gradualism

Punctuated gradualism is a microevolutionary hypothesis that refers to a species that has “relative stasis over a considerable part of its total duration [and] underwent periodic, relatively rapid, morphologic change that did not lead to lineage branching”. It is one of the three common models of evolution. While the traditional model of palaeontology, the phylogenetic model, states that features evolved slowly without any direct association with speciation, the relatively newer and more controversial idea of punctuated equilibrium claims that major evolutionary changes don’t happen over a gradual period but in localized, rare, rapid events of branching speciation. Punctuated gradualism is considered to be a variation of these models, lying somewhere in between the phyletic gradualism model and the punctuated equilibrium model. It states that speciation is not needed for a lineage to rapidly evolve from one equilibrium to another but may show rapid transitions between long-stable states.


Problems to be Solved

No solution is perfect. Though this one helps clarify a confused situation, there are still several problems that need to be discussed regarding the new concept of “actualism.” I will mention three, noting that Hooykaas (1970, p. 275) discussed them first:

The first problem is the ambiguity of the term “present.” What period of time is encompassed? It seems at the very least that it must be restricted to periods when reasonable scientific observation and description are available, but that is an arbitrary and subjective limit, based on pragmatic necessity, not logical criteria that are determinative of geological processes. Furthermore, that time changes depending on where the observations were taking place. Reliable documentation of processes in Western Europe may date back into the seventeenth century, while knowledge of the Polar Regions or the deep oceans are still quite limited. That is one reason that the small caveat noted by Hooykaas (1970, p. 315) should be observed, that “Actualism, on the other hand, covers a wide range of theories…that go together with the methodological principle of being as ‘actualistic’ as the geological facts admit…”

This is similar to Austin’s (1979, p. 39) emphasis on the rock record rather than a priori systems of interpretation. He recognized that interpretation was complicated by:

This is a more reasonable approach to geohistory, and one that de-emphasizes the dogmatism that has encumbered the discipline for so many years. Catastrophists and gradualists could work well together if both respected the non-absolute nature of historical interpretation.

The second ambiguity is in defining a “geological cause.” Historically, imprecision in this concept has forced geologists over and over again back to physical and chemical laws, yet these are not specifically determinative of geological events. Simpson (1963) struggled with relating “immanent” physical laws to geological “configurations” of earth’s past. It may be that geological causes will always have a degree of imprecision and resulting uncertainty, but attempting to constrain them more completely is a goal that today’s neocatastrophists should embrace.

Ironically, Baker (1998) urged a reverse concept learning from the rocks. He advocated a nonactualistic approach, where reasonable hypotheses would develop from a systematic study of the ancient rock record, rather than the attempt to impose modern environments and causes onto the rocks. In today’s heady revolutions in the earth sciences, that is certainly a methodological proposal that bears closer scrutiny.

The third problem is a corollary of defining geological causes. The problem is that introduced by scale. When does a quantitative change in rate or intensity of a particular geological cause create a qualitative change in the geologic process itself? Gradualists never had to face this uncomfortable question, but if today’s geologists are set on neocatastrophism, then they must address it head on.


Hutton’s contributions

The idea that the laws that govern geologic processes have not changed during Earth’s history was first expressed by Scottish geologist James Hutton, who in 1785 presented his ideas—later published in two volumes as Theory of the Earth (1795)—at meetings of the Royal Society of Edinburgh. Hutton showed that Earth had a long history that could be interpreted in terms of processes observed in the present. He showed, for instance, how soils were formed by the weathering of rocks and how layers of sediment accumulated on Earth’s surface.

He also stated that there was no need of any preternatural cause to explain the geologic record. Hutton’s proposal challenged the concept of a biblical Earth (with a history of some 6,000 years) that was created especially to be a home for human beings the effect of his ideas on the learned world can be compared only the earlier revolution in thought brought about by Polish astronomer Nicolaus Copernicus, German astronomer Johannes Kepler, and Italian astronomer Galileo when they displaced the concept of a universe centred on Earth with the concept of a solar system centred on the Sun. Both advances challenged existing thought and were fiercely resisted for many years.

In Principles of Geology, 3 vol. (1830–33), Scottish geologist Sir Charles Lyell deciphered Earth’s history by employing Huttonian principles and made available a host of new geologic evidence supporting the view that physical laws are permanent and that any form of supernaturalism could be rejected. Lyell’s work in turn profoundly influenced English naturalist Charles Darwin, who recognized Lyell as having produced a revolution in science.


Differences between Gradualism and Uniformitarianism - Biology

Uniformitarianism: Charles Lyell

Discrete rock layers containing different fossils reinforced the idea that the Earth's history could be divided into ages marked by catastrophic change. However, gradual change, like that caused by erosion, has also played an important role in the Earth's history.

Thanks to the pioneering work of researchers such as William Smith, geologists in the early 1800s were able to swiftly organize rock formations into a single colossal record of Earth's history. Many geologists saw in this record a stormy epic, one in which our planet had been convulsed repeatedly by abrupt changes. Mountains were built in catastrophic instants, and in the process whole groups of animals became extinct and were replaced by new species. Giant tropical plants, for example, left their fossils in northern Europe during the Carboniferous Period, never to be seen there again. Earth's history might not fit a strict Biblical narrative any longer, but these revolutions seemed to be a sign that it did have a direction. From its formation, catastrophes altered the planet’s surface step by step leading towards the present Earth. Life, likewise, had its own arrow through time.

Catastrophism
Even before this geological evidence had emerged, some naturalists had already claimed that Earth's history had a direction. Buffon, and later the physicist Joseph Fourier, both claimed that the Earth had begun as a hot ball of molten rock and had been cooling through time. Fourier argued that the tropical plants of Europe must have lived during those warmer times. Some geologists suggested that the cooling of the planet occasionally triggered violent, sudden uplifts of mountains and volcanic eruptions.

The ideas of Hutton and Lyell led to an understanding of "the rock cycle" as we know it today.
Gradual change
For inspiration, Lyell turned to the fifty-year-old ideas of a Scottish farmer named James Hutton. In the 1790s, Hutton had argued that the Earth was transformed not by unimaginable catastrophes but by imperceptibly slow changes, many of which we can see around us today. Rain erodes mountains, while molten rock pushes up to create new ones. The eroded sediments form into layers of rock, which can later be lifted above sea level, tilted by the force of the uprising rock, and eroded away again. These changes are tiny, but with enough time they could produce vast changes. Hutton therefore argued that the Earth was vastly old — a sort of perpetual-motion machine passing through regular cycles of destruction and rebuilding that made the planet suitable for mankind.

Lyell found evidence that valleys were formed through the slow process of erosion, not by catastrophic floods.

Lyell traveled through Europe to find more evidence that gradual changes, the same we can see happening today, had produced the features of the Earth's surface. He found evidence for many rises and falls of sea level, and of giant volcanoes built on top of far older rocks. Processes such as earthquakes and eruptions, which had been witnessed by humans, were enough to produce mountain ranges. Valleys were not the work of giant floods but the slow grinding force of wind and water.

Uniform Processes of Change
Lyell's version of geology came to be known as uniformitarianism, because of his fierce insistence that the processes that alter the Earth are uniform through time. Like Hutton, Lyell viewed the history of Earth as being vast and directionless. And the history of life was no different.

Lyell crafted a powerful lens for viewing the history of the Earth. On Darwin's voyage aboard the Beagle, for example, he was able to decipher the history of the Canary Islands (right) by applying Lyell's ideas to the volcanic rock he encountered there. Today satellite measurements reveal that mountains may rise an inch a year, while radioactive clocks help show how they've been rising that way for millions of years. But Lyell could never have grasped the mechanism — plate tectonics — that makes this kind of geological change happen.

Yet geologists today also know that some of the factors that changed the Earth in the past cannot be seen at work today. For example, the early Earth was pummeled by gigantic hunks of solar debris, some as big as Mars. For the first one or two billion years of Earth's history, plate tectonics didn't even exist as we know it today.

Lyell had an equally profound effect on our understanding of life's history. He influenced Darwin so deeply that Darwin envisioned evolution as a sort of biological uniformitarianism. Evolution took place from one generation to the next before our very eyes, he argued, but it worked too slowly for us to perceive.