This website uses cookies to ensure you get the best experience on our website. Learn more

The neutral theory of ecology

x

The neutral theory of ecology

MIT 8.591J Systems Biology, Fall 2014
View the complete course:
Instructor: Jeff Gore

In this lecture, Prof. Jeff Gore asks why are some species abundant and others rare? Are there universal patterns at play? And what lead to these patterns?

License: Creative Commons BY-NC-SA
More information at
More courses at

biodiversity-niche theory

Made with Explain Everything
x

Ecological Neutral Theory: is it Madness or Misunderstood? (James Rosindell October 2013)

A full video of James Rosindell's seminar presentation on 31st October 2013 at the University of York. This is an introduction to ecological neutral theory and its applications. The presentation also includes new research not yet published elsewhere and a demonstration of the OneZoom tree of life explorer (

Neutral Theory of Molecular Evolution

x

Rosindell: A Nearly Neutral Theory of Ecology and Macroevolution

Presentation by Rosindell James, with coauthors Rampal Etienne and Luke Harmon
Evolution 2014 conference

The neutral theory of biodiversity and other competitors to maximum entropy

Annette Ostling (Univ. of Michigan) gave a talk entitled The neutral theory of biodiversity and other competitors to maximum entropy, at the Information and Entropy Investigative Workshop, held at NIMBioS 8-10 April 2015. To read more about the workshop, click the following link:
x

4. Neutral Evolution: Genetic Drift

Principles of Evolution, Ecology and Behavior (EEB 122)

Neutral evolution occurs when genes do not experience natural selection because they have no effect on reproductive success. Neutrality arises when mutations in an organism's genotype cause no change in its phenotype, or when changes in the genotype bring about changes in the phenotype that do not affect reproductive success. Because neutral genes do not change in any particular direction over time and simply drift, thanks in part to the randomness of meiosis, they can be used as a sort of molecular clock to determine common ancestors or places in the phylogenetic tree of life.

00:00 - Chapter 1. Introduction
04:56 - Chapter 2. Genes and Amino Acid Changes Not Reflected in Phenotypes
14:29 - Chapter 3. Neutral Evolution in the History of Life
20:38 - Chapter 4. Mechanisms of Neutral or Random Evolution
35:28 - Chapter 5. The Molecular Clock of Neutral Evolution

Complete course materials are available at the Open Yale Courses website:

This course was recorded in Spring 2009.

John Maynard Smith - Kimura and King: Neutral theory of molecular evolution (84/102)

To hear more of John Maynard Smith’s stories, go to the playlist:

The late British biologist John Maynard Smith (1920-2004) is famous for applying game theory to the study of natural selection. In 1973 Maynard Smith formalised a central concept in game theory called the evolutionarily stable strategy (ESS). His ideas, presented in books such as 'Evolution and the Theory of Games', were enormously influential and led to a more rigorous scientific analysis and understanding of interactions between living things. [Listener: Richard Dawkins]

TRANSCRIPT: I had a slightly curious position on that when the serious debates were going on. I mean, when Kimura's paper was published... Kimura and King, it's - one's so bad at dates, 1961, could it be? - anyway, whenever, when it was first published, this led, particularly in Britain, to deep hostility to the notion that anything could be selectively neutral. The whole tradition of British population biology had been if you find a genetic variability, it must have some kind of selective explanation, and if at first you don't find it, you must try, try and try again, until you do. And the suggestion that there were genetic changes out there which were selectively neutral, was really deeply distasteful to these people. And there was really quite an extraordinary level of debate on the issue. Which... and what seemed to me so strange at the time, that people felt they had to take sides. I remember, it was at its height at a period when Dick Lewontin spent a year in my lab here. And I remember we talked about it and we both agreed that at the moment we couldn't see anything really decisive, one way or the other. And we kept on trying to think of decisive statistical measures or experiments one could carry out, to decide whether the neutral theory was true. And we kept on coming up with ideas and then deciding that they wouldn't really settle the issue, because, you know. And so we both agreed the only sensible thing was to do was to say we don't know, it didn't seem to be necessary in science to say you know when you don't. But almost everybody else seemed to take rigorous sides. I think that the... this degree of polarity has disappeared, and I think today most people who've thought about the matter seriously, really see the value of the neutral theory as a kind of null hypothesis. The great beauty of the neutral theory is it says, there is no selection. It is then possible to work out, in great detail, what you expect to happen, and what you expect to happen to distribution of gene frequencies, their rates of change in time, and all sorts of things of that kind. Once you start saying there's selection, anything goes, because you don't know what the selection is, you can't predict anything. And so the neutral theory provides one with a really admirable sort of null hypothesis against a background to which you can... you can pick out the cases where clearly it's not neutral, and you can say, 'That's selective because it doesn't agree with the neutral hypothesis.' So, I've no doubt at all that Kimura's contribution was profound and really has changed population genetics.

John Maynard Smith - Inspiring Kimura to write "The Neutral Theory of Molecular Evolution" (86/102)

To hear more of John Maynard Smith’s stories, go to the playlist:

The late British biologist John Maynard Smith (1920-2004) is famous for applying game theory to the study of natural selection. In 1973 Maynard Smith formalised a central concept in game theory called the evolutionarily stable strategy (ESS). His ideas, presented in books such as 'Evolution and the Theory of Games', were enormously influential and led to a more rigorous scientific analysis and understanding of interactions between living things. [Listener: Richard Dawkins]

TRANSCRIPT: When I published my sex book, The Evolution of Sex, I sent a copy to Motoo with a covering letter saying 'You'll find a lot of your ideas in this book,' which is true. And he wrote back a really typical Kimura letter, he wrote back saying 'Dear John, many thanks for sending me your book.' He then obviously can't think of anything polite to say about it, so he says, 'It is, however, very beautifully printed.' He then goes on to say, 'But, I feel you ought to know that equation 167 was, in fact, reached by Jim Crow and myself in a chapter of our text book which we finally didn't include in the final edition, but you ought to know that we did.' Because he's very obsessional about priorities, Motoo. But, still, the book is very beautifully printed - however, so deep is the hostility of all British geneticists to my work that there is no chance that I would ever have published a book with such a beautiful printer. I rang up my contact at Cambridge University Press and said, 'Look, I think if you play your cards right, you can get a book out of Motoo.' And so that's why they published The Neutral Theory [of Molecular Evolution]. The other thing about that book - I wrote a review of it in Nature, which in general was very complimentary, because it's a great book - come on. But I did point out that he does say, in the first chapter of the book, that - I can't remember the exact words, but it's roughly something like; 'Of course, morphological structure has evolved by natural selection acting on random mutation.' And then he goes on to say that it's all the molecular stuff he's going to talk about, which [he] hasn't. And I quoted this in my review because it seemed to me that people would take, certainly the sort of, British naive panselectionists, would take what he had to say about molecules more seriously if they realised that he accepted the Darwinian explanation of the evolution they were interested in. And after the review appeared, I was rung up by Jim Crow, who, you know, was the... I'm not sure, I think Motoo took a post-doctoral period with Jim, but obviously Jim was his teacher in an important way, and indeed, he's very proud of being his teacher, but I think, actually, he's rightly proud, I mean, I think he did a great job. Jim rang me up and said he was so pleased that I'd written such a nice review of Kimura's book in Nature, but he thought I might like to know how that sentence got into the book. And I said, 'Well, I'd assumed because Motoo wrote it.' He said, 'Well, not quite.' And he said, 'What actually happened was that when Motoo showed me the text of the book, I said, Look, Motoo, if somewhere in the beginning you said, look, I accept natural selection as an explanation of morphological evolution, it'll make people more sympathetic to the rest of the book.' And Motoo said, 'Right, I will.' 'But,' he said, 'the pen wouldn't write down the words, and ultimately Jim wrote that sentence.' But still, Kimura put it into the book and signed it, so, you know, he clearly did believe it, it was just he couldn't write it.

What is NEUTRAL MUTATION? What does NEUTRAL MUTATION mean? NEUTRAL MUTATION meaning

What is NEUTRAL MUTATION? What does NEUTRAL MUTATION mean? NEUTRAL MUTATION meaning - NEUTRAL MUTATION definition - NEUTRAL MUTATION explanation.

Source: Wikipedia.org article, adapted under license.

Neutral mutations are changes in DNA sequence that are neither beneficial nor detrimental to the ability of an organism to survive and reproduce. In population genetics, mutations in which natural selection does not affect the spread of the mutation in a species are termed neutral mutations. Neutral mutations that are inheritable and not linked to any genes under selection will either be lost or will replace all other alleles of the gene. This loss or fixation of the gene proceeds based on random sampling known as genetic drift. A neutral mutation that is in linkage disequilibrium with other alleles that are under selection may proceed to loss or fixation via genetic hitchhiking and/or background selection.

While many mutations in a genome may decrease an organism’s ability to survive and reproduce, also known as fitness, these mutations are selected against and not passed on to future generations. The most commonly observed mutations detectable as variation in the genetic makeup of organisms and populations appear to have no visible effect on the fitness of individuals and are therefore neutral. The identification and study of neutral mutations has led to the development of the neutral theory of molecular evolution. The neutral theory of molecular evolution is an important and often controversial theory proposing that most molecular variation within and among species is essentially neutral and not acted on by selection. Neutral mutations are also the basis for using molecular clocks to identify such evolutionary events as speciation and adaptive or evolutionary radiations.

Charles Darwin commented on the idea of neutral mutation in his work, hypothesizing that mutations that do not give an advantage or disadvantage may fluctuate or become fixed apart from natural selection. Variations neither useful nor injurious would not be affected by natural selection, and would be left either a fluctuating element, as perhaps we see in certain polymorphic species, or would ultimately become fixed, owing to the nature of the organism and the nature of the conditions. While Darwin is widely credited with introducing the idea of natural selection which was the focus of his studies, he also saw the possibility for changes that did not benefit or hurt an organism.

Darwin's view of change being mostly driven by traits that provide advantage was widely accepted until the 1960s. While researching mutations that produce nucleotide substitutions in 1968, Motoo Kimura found that the rate of substitution was so high that if each mutation improved fitness, the gap between the most fit and typical genotype would be implausibly large. However, Kimura explained this rapid rate of mutation by suggesting that the majority of mutations were neutral, i.e. had little or no effect on the fitness of the organism. Kimura developed mathematical models of the behavior of neutral mutations subject to random genetic drift in biological populations. This theory has become known as the neutral theory of molecular evolution.

As technology has allowed for better analysis of genomic data, research has continued in this area. While natural selection may encourage adaptation to a changing environment, neutral mutation may push divergence of species due to nearly random genetic drift.
x

Community ecology: History and theory

In this first of three lectures on community ecology, Dr. Dan Simberloff presents an overview of of community ecology, and highlights some of the foundational theorists in the field. He offers a definition of the field, which focuses on understanding how many species live in a geographically defined community, and why particular species do or do not coexist in the same community. He provides examples of historical and contemporary empirical studies that have structured and contributed to Darwin’s theory of naturalization, Elton’s ideas about species ratios and diversity, and Gause’s competitive exclusion principle. He also highlights more recent theories of limiting similarity and priority effects, and the temporal dimensions of changes in community composition.

More information on the Immersion Program and other lectures can be found here:

Theory I: Ecological niches and geographic distributions

This is the first part of a training course on Species Distribution Modelling (also called Ecological Niche Modelling) taught by Richard Pearson at University College London in November 2014. The talk introduces correlative and mechanistic approaches for predicting species distributions, ecological niche theory, and the distinction between estimating geographic distributions and ecological niches. Funding was provided by the UK Natural Environment Research Council (NERC).
x

Will Provine on the Neutral Theory

William B. Provine (Cornell University) talks about the development of the neutral and nearly neutral theories of molecular evolution by Motoo Kimura and Tomoko Ohta. This video was recorded at the Dibner-MBL Seminar on Perspectives on Molecular Evolution in May 2004, and it's available from

Unified neutral theory of biodiversity | Wikipedia audio article

This is an audio version of the Wikipedia Article:



00:02:02 1 Saturation
00:03:35 1.1 Species abundances
00:19:27 2 Stochastic modelling of species abundances under the UNTB
00:27:23 3 Species-area relationships
00:31:41 3.1 Example
00:35:08 4 Dynamics under neutral hypothesis
00:39:44 5 Testing the theory
00:40:55 6 See also



Listening is a more natural way of learning, when compared to reading. Written language only began at around 3200 BC, but spoken language has existed long ago.

Learning by listening is a great way to:
- increases imagination and understanding
- improves your listening skills
- improves your own spoken accent
- learn while on the move
- reduce eye strain

Now learn the vast amount of general knowledge available on Wikipedia through audio (audio article). You could even learn subconsciously by playing the audio while you are sleeping! If you are planning to listen a lot, you could try using a bone conduction headphone, or a standard speaker instead of an earphone.

Listen on Google Assistant through Extra Audio:

Other Wikipedia audio articles at:

Upload your own Wikipedia articles through:




There is only one good, knowledge, and one evil, ignorance.
- Socrates



SUMMARY
=======
The unified neutral theory of biodiversity and biogeography (here Unified Theory or UNTB) is a hypothesis and the title of a monograph by ecologist Stephen Hubbell. The hypothesis aims to explain the diversity and relative abundance of species in ecological communities, although like other neutral theories of ecology, Hubbell's hypothesis assumes that the differences between members of an ecological community of trophically similar species are neutral, or irrelevant to their success. This implies that biodiversity arises at random, as each species follows a random walk. The hypothesis has sparked controversy, and some authors consider it a more complex version of other null models that fit the data better.Neutrality means that at a given trophic level in a food web, species are equivalent in birth rates, death rates, dispersal rates and speciation rates, when measured on a per-capita basis. This can be considered a null hypothesis to niche theory. Hubbell built on earlier neutral concepts, including MacArthur & Wilson's theory of island biogeography and Gould's concepts of symmetry and null models.An ecological community is a group of trophically similar, sympatric species that actually or potentially compete in a local area for the same or similar resources. Under the Unified Theory, complex ecological interactions are permitted among individuals of an ecological community (such as competition and cooperation), provided that all individuals obey the same rules. Asymmetric phenomena such as parasitism and predation are ruled out by the terms of reference; but cooperative strategies such as swarming, and negative interaction such as competing for limited food or light are allowed (so long as all individuals behave in the same way).
The Unified Theory also makes predictions that have profound implications for the management of biodiversity, especially the management of rare species.The theory predicts the existence of a fundamental biodiversity constant, conventionally written θ, that appears to govern species richness on a wide variety of spatial and temporal scales.

4. Neutral Evolution: Genetic Drift

Principles of Evolution, Ecology and Behavior (EEB 122) Neutral evolution occurs when genes do not experience natural selection because they have no effect on reproductive success. Neutrality.

Hank talks about population genetics, which helps to explain the evolution of populations over time by combing the principles of Mendel and Darwin, and by means of the Hardy-Weinberg equation..

003 - Genetic Drift Paul Andersen describes genetic drift as a mechanism for evolutionary change. A population genetics simulator is used to show the importance of large population size in.
x

Bronfenbrenner's Ecological Theory

Bronfenbrenner's Ecological Theory

What is ECOLOGICAL-EVOLUTIONARY THEORY? What does ECOLOGICAL-EVOLUTIONARY THEORY mean?

What is ECOLOGICAL-EVOLUTIONARY THEORY? What does ECOLOGICAL-EVOLUTIONARY THEORY mean? ECOLOGICAL-EVOLUTIONARY THEORY meaning - ECOLOGICAL-EVOLUTIONARY THEORY definition - ECOLOGICAL-EVOLUTIONARY THEORY explanation.

Source: Wikipedia.org article, adapted under license.

SUBSCRIBE to our Google Earth flights channel -

Ecological-evolutionary theory (EET) is a sociological theory of sociocultural evolution that attempts to explain the origin and changes of society and culture. Key elements focus on the importance of natural environment and technological change. EET has been described as a theory of social stratification, as it analyzes how stratification has changed through time across different societies. It also has been viewed as a synthesis of the structural functionalism and conflict theory. Proposed by Gerhard Lenski, the theory perhaps is best articulated in his book, Ecological-Evolutionary Theory: Principles and Applications (2005). His major collaborators, Jean Lenski and Patrick Nolan, also are said to have contributed to EET.

Lenski notes that society and culture evolve through symbols, which makes this process much more rapid, deliberative, and purposeful, compared to biological evolution. However, just like in the biological survival of the fittest, in sociocultural evolution there is a process of intersocietal selection, where less fit sociocultural systems became extinct, replaced by more efficient ones. In another analogy to biological evolution, Lenski argues that the sociocultural systems that survive do so primarily on the virtue of their level of technological advancement, which otherwise is blind and purposeless as the outcome of the biological process of natural selection and just as indifferent to humans beliefs and values. Thus, Lenski does not argue that societies that survive are morally superior to those that are defeated—simply that they were more efficient at technological progress. This, in turn, helps those societies survive and grow. Technologies can thus be compared to genes of a society, providing it with new abilities, as new technologies allow it to do things that it could not have done before.

Technology is a factor whose importance Lenski stresses above all others, and he differentiates societies by their technology level, into hunter gatherers, simple and complex horticulture, agrarian societies and industrial societies. At the same time, characteristics of a society go beyond technology, into its demographic and genetic characteristics; culture, including material; social organization and institutions. Natural environment also plays a role, as does geographical location in general; as isolated societies have less chance to benefit from interaction with others.

Lenski's theory focus on material infrastructure of societies (growth in population and economic relations), and as such has been described as materialist. It builds on classic theories of Thomas Malthus and Herbert Spencer in seeing society and culture a products of nature (human beings), thus subject to natural law. Lenski argues that humans often act against the interests of the society, which he attributes to self-interest and individualism, themselves products of differing life experiences. He notes that different societies survive thanks to their subsistence strategies, which allow them to draw resources (energy) from the environment; those strategies are determined by technologies possessed by those societies, itself significantly determined by demography (population and its growth) and economy systems (division of labor). Technology, defined by him as information about the ways in which resources in the environment may be used to satisfy human needs and desires, is the most important element of the sociocultural system.

Lenski further argues that sociocultural change is an effect of either interaction with a different society and culture, or a result of environment change (from natural ones, like ice ages, to man-made ones, like resource depletion). Humans primary way of dealing with changing environment is a self-reinforcing development of technology, through innovation is in general less common than copying solutions invented by others (cultural diffusion)......

Parents: Through the Lens of Ecology Theory

On the ways in which ecology theory might help us to contextualise our interactions with parents.

Neutral theory of molecular evolution | Wikipedia audio article

This is an audio version of the Wikipedia Article:



00:01:38 1 Overview
00:05:24 2 The neutralist–selectionist debate
00:07:31 3 See also



Listening is a more natural way of learning, when compared to reading. Written language only began at around 3200 BC, but spoken language has existed long ago.

Learning by listening is a great way to:
- increases imagination and understanding
- improves your listening skills
- improves your own spoken accent
- learn while on the move
- reduce eye strain

Now learn the vast amount of general knowledge available on Wikipedia through audio (audio article). You could even learn subconsciously by playing the audio while you are sleeping! If you are planning to listen a lot, you could try using a bone conduction headphone, or a standard speaker instead of an earphone.

Listen on Google Assistant through Extra Audio:

Other Wikipedia audio articles at:

Upload your own Wikipedia articles through:




There is only one good, knowledge, and one evil, ignorance.
- Socrates



SUMMARY
=======
The neutral theory of molecular evolution holds that at the molecular level most evolutionary changes and most of the variation within and between species is not caused by natural selection but by genetic drift of mutant alleles that are neutral. A neutral mutation is one that does not affect an organism's ability to survive and reproduce. The neutral theory allows for the possibility that most mutations are deleterious, but holds that because these are rapidly removed by natural selection, they do not make significant contributions to variation within and between species at the molecular level. Mutations that are not deleterious are assumed to be mostly neutral rather than beneficial. In addition to assuming the primacy of neutral mutations, the theory also assumes that the fate of neutral mutations is determined by the sampling processes described by specific models of random genetic drift.The theory was introduced by the Japanese biologist Motoo Kimura in 1968, and independently by two American biologists Jack Lester King and Thomas Hughes Jukes in 1969, and described in detail by Kimura in his 1983 monograph The Neutral Theory of Molecular Evolution. According to Kimura, the theory applies only for evolution at the molecular level, and phenotypic evolution is controlled by natural selection, as postulated by Charles Darwin. The proposal of the neutral theory was followed by an extensive neutralist-selectionist controversy over the interpretation of patterns of molecular divergence and polymorphism, peaking in the 1970s and 1980s. Since then, much evidence has been found for selection at molecular level.

Neutral Evolution Pt. 04

Randy Linder

Shares

x

Check Also

x

Menu