Faculty Opinions recommendation of Natural selection and developmental constraints in the evolution of allometries.

AbstractEvolution acts through a combination of four different drivers: (1) mutation, (2) selection, (3) genetic drift, and (4) developmental constraints. There is a tendency among some biologists to frame evolution as the sole result of natural selection, and this tendency is reinforced by many popular texts. “The Naked Ape” by Desmond Morris, published 50 years ago, is no exception. In this paper I argue that evolutionary biology is much richer than natural selection alone. I illustrate this by reconstructing the evolutionary history of five different organs of the human body: foot, pelvis, scrotum, hand and brain. Factors like developmental tinkering, by-product evolution, exaptation and heterochrony are powerful forces for body-plan innovations and the appearance of such innovations in human ancestors does not always require an adaptive explanation. While Morris explained the lack of body hair in the human species by sexual selection, I argue that molecular tinkering of regulatory genes expressed in the brain, followed by positive selection for neotenic features, may have been the driving factor, with loss of body hair as a secondary consequence.

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Evo-devo and accounting for Darwin's endless forms

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2011.0007 ◽

2011 ◽

Vol 366 (1574) ◽

pp. 2069-2075 ◽

Cited By ~ 60

Author(s):

Paul M. Brakefield

Keyword(s):

Natural Selection ◽

Common Ancestry ◽

Developmental Constraints ◽

Evolutionary Diversification ◽

New Genes ◽

The Earth ◽

Regulatory Machinery ◽

Evo Devo ◽

Opening Up ◽

Trait Space

Evo-devo has led to dramatic advances in our understanding of how the processes of development can contribute to explaining patterns of evolutionary diversification that underlie the endless forms of animal life on the Earth. This is increasingly the case not only for the origins of evolutionary novelties that permit new functions and open up new adaptive zones, but also for the processes of evolutionary tinkering that occur within the subsequent radiations of related species. Evo-devo has time and again yielded spectacular examples of Darwin's notions of common ancestry and of descent with modification. It has also shown that the evolution of endless forms is more about the evolution of the regulatory machinery of ancient genes than the origin and elaboration of new genes. Evolvability, especially with respect to the capacity of a developmental system to evolve and to generate the variation in form for natural selection to screen, has become a pivotal focus of evo-devo. As a consequence, a balancing of the concept of endless forms in morphospace with a greater awareness of the potential for developmental constraints and bias is becoming more general. The prospect of parallel horizons opening up for the evolution of behaviour is exciting; in particular, does Sean Carroll's phrase referring to old genes learning new tricks in the evolution of endless forms apply equally as well to patterns of diversity and disparity in behavioural trait-space?

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Evolutionary origins of sexual dimorphism : Lessons from female-limited mimicry in butterflies.

10.1101/2021.07.09.451774 ◽

2021 ◽

Author(s):

Ludovic Maisonneuve ◽

Charline Smadi ◽

Violaine LLAURENS

Keyword(s):

Natural Selection ◽

Female Preference ◽

Sympatric Species ◽

Sexually Dimorphic ◽

Complex Interplay ◽

Developmental Constraints ◽

Text Book ◽

Male And Female ◽

Evolutionary Origins ◽

Alternative Hypotheses

The surprising female-limited mimicry observed in some species is a text-book example of sexually-dimorphic trait submitted to intense natural selection. Two main hypotheses have been proposed to explain female-limited mimicry in butterflies. Predation pressure favouring mimicry could be higher in females because of their slower flight, and overcome developmental constraints favouring the ancestral trait that limits the evolution of mimicry in males but not in females. Alternatively, the evolution of mimicry in males could be limited by sexual selection, generated by females preference for non-mimetic males. However, the evolutionary origin of female preference for non-mimetic males remains unclear. Here, we hypothesise that costly sexual interactions between individuals from distinct sympatric species might intensify because of mimicry, therefore promoting female preference for non-mimetic trait. Using a mathematical model, we compare the evolution of female-limited mimicry when assuming either alternative hypotheses. We show that the patterns of divergence of male and female trait from the ancestral traits can differ between these selection regimes but we specifically highlight that divergence in females trait is not a signature of the effect of natural selection. Altogether, our model reveals the complex interplay between sexual and natural selection shaping the evolution of sexually-dimorphic traits.

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Brain evolution and development: adaptation, allometry and constraint

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2016.0433 ◽

2016 ◽

Vol 283 (1838) ◽

pp. 20160433 ◽

Cited By ~ 35

Author(s):

Stephen H. Montgomery ◽

Nicholas I. Mundy ◽

Robert A. Barton

Keyword(s):

Body Size ◽

Natural Selection ◽

Comparative Studies ◽

Brain Evolution ◽

Phenotypic Traits ◽

Functional Constraints ◽

Developmental Constraints ◽

Functional Systems ◽

Evolution And Development ◽

Developmental Mechanisms

Phenotypic traits are products of two processes: evolution and development. But how do these processes combine to produce integrated phenotypes? Comparative studies identify consistent patterns of covariation, or allometries, between brain and body size, and between brain components, indicating the presence of significant constraints limiting independent evolution of separate parts. These constraints are poorly understood, but in principle could be either developmental or functional. The developmental constraints hypothesis suggests that individual components (brain and body size, or individual brain components) tend to evolve together because natural selection operates on relatively simple developmental mechanisms that affect the growth of all parts in a concerted manner. The functional constraints hypothesis suggests that correlated change reflects the action of selection on distributed functional systems connecting the different sub-components, predicting more complex patterns of mosaic change at the level of the functional systems and more complex genetic and developmental mechanisms. These hypotheses are not mutually exclusive but make different predictions. We review recent genetic and neurodevelopmental evidence, concluding that functional rather than developmental constraints are the main cause of the observed patterns.

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Why call it developmental bias when it is just development?

Biology Direct ◽

10.1186/s13062-020-00289-w ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Isaac Salazar-Ciudad

Keyword(s):

Natural Selection ◽

Morphological Variation ◽

Morphological Evolution ◽

Developmental Constraints ◽

Evolution And Development ◽

Different Types ◽

Change Of Perspective ◽

Opinion Article ◽

Main Factor

AbstractThe concept of developmental constraints has been central to understand the role of development in morphological evolution. Developmental constraints are classically defined as biases imposed by development on the distribution of morphological variation.This opinion article argues that the concepts of developmental constraints and developmental biases do not accurately represent the role of development in evolution. The concept of developmental constraints was coined to oppose the view that natural selection is all-capable and to highlight the importance of development for understanding evolution. In the modern synthesis, natural selection was seen as the main factor determining the direction of morphological evolution. For that to be the case, morphological variation needs to be isotropic (i.e. equally possible in all directions). The proponents of the developmental constraint concept argued that development makes that some morphological variation is more likely than other (i.e. variation is not isotropic), and that, thus, development constraints evolution by precluding natural selection from being all-capable.This article adds to the idea that development is not compatible with the isotropic expectation by arguing that, in fact, it could not be otherwise: there is no actual reason to expect that development could lead to isotropic morphological variation. It is then argued that, since the isotropic expectation is untenable, the role of development in evolution should not be understood as a departure from such an expectation. The role of development in evolution should be described in an exclusively positive way, as the process determining which directions of morphological variation are possible, instead of negatively, as a process precluding the existence of morphological variation we have no actual reason to expect.This article discusses that this change of perspective is not a mere question of semantics: it leads to a different interpretation of the studies on developmental constraints and to a different research program in evolution and development. This program does not ask whether development constrains evolution. Instead it asks questions such as, for example, how different types of development lead to different types of morphological variation and, together with natural selection, determine the directions in which different lineages evolve.

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La funcionalidad, si existe, no deriva de un propósito. Una argumentación desde la biomorfodinámica y la evo-devo

Contrastes Revista Internacional de Filosofía ◽

10.24310/contrastescontrastes.v0i0.1164 ◽

2013 ◽

Author(s):

Miquel De Renzi

Keyword(s):

Natural Selection ◽

El Paso ◽

Developmental Constraints ◽

Adult Organism ◽

Independent Features ◽

Evo Devo ◽

Previous Step

RESUMENLa noción de propósito es inherente a la finalidad (adaptación, función) si se toma ésta como causa principal de las estructuras orgánicas. Éstas surgen a través del desarrollo, que tiene una causalidad propia, sin propósito con respecto al organismo adulto. El desarrollo esta canalizado y sujeto a limitaciones (constraints); por ello, no se alcanzan óptimos adaptativos en general. Sobre tales posibilidades limitadas en variabilidad actúa la selección natural; la modularidad permite combinar selectivamente aspectos independientes, pero siempre dentro de limitaciones. Pueden surgir estructuras no funcionales que llegarán –o no– a constituir exaptaciones, que serán el paso previo a toda adaptación.PALABRAS-CLAVEADAPTACIONISMO, EXAPTACIÓN, CANALIZACIÓN, LIMITACIÓN DE DESARROLLO, MODULARIDADABSTRACTThe notion of design is inherent to finality (adaptation, function) if this last one is taken as the main cause of organic structures. Structures arise throughout development, which has its own causation, decoupled from the design referred to the adult organism. Development is canalized and subjected to constraints; because of this, adaptive optima are not generally reached. Natural selection works on these possibilities of constrained variability; modularity allows the selective combination for independent features, but always within a constrained framework. Nonfunctional structures are expected, which will arrive –or not– to give exaptations, the previous step to any adaptation.KEYWORDSADAPTATIONISM, EXAPTATION, CANALIZATION, DEVELOPMENTAL CONSTRAINTS, MODULARITY

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