Convergent evolution and the limits of natural selection

Four natural phenomena are cited for their defiance of conventional neo-Darwinian analysis: human intelligence; cat domesticity; the Cambrian explosion; and convergent evolution. 1. Humans are now far more intelligent than needed in their hunting–gathering days >10,000 years ago. 2. Domestic cats evolved from wildcats via major genetic and physical changes, all occurring in less than 12,000 years. 3. The Cambrian explosion refers to the remarkable expansion of species that mystifies evolutionists, as there is a total lack of fossil evidence for precursors of this abundant new life. 4. Convergent evolution often involves formation of complex, multigene traits in two or more species that have no common ancestor. These four evolutionary riddles are discussed in terms of a proposed “preassembly” mechanism in which genes and gene precursors are collected silently and randomly over extensive time periods within huge non-coding sections of DNA. This is followed by epigenetic release of the genes, when the environment so allows, and by natural selection. In neo-Darwinism, macroevolution of complex traits involves multiple mutation/selections, with each of the resulting intermediates being more favorable to the species than the previous one. Preassembly, in contrast, invokes natural selection only after a partially or fully formed trait is already in place. Preassembly does not supplant neo-Darwinism but, instead, supplements neo-Darwinism in those important instances where the classical theory is wanting.

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Convergent evolution of ‘creepers’ in the Hawaiian honeycreeper radiation

Biology Letters ◽

10.1098/rsbl.2008.0589 ◽

2008 ◽

Vol 5 (2) ◽

pp. 221-224 ◽

Cited By ~ 20

Author(s):

Dawn M Reding ◽

Jeffrey T Foster ◽

Helen F James ◽

H. Douglas Pratt ◽

Robert C Fleischer

Keyword(s):

Natural Selection ◽

Adaptive Radiation ◽

Phylogenetic Relationships ◽

Convergent Evolution ◽

Nuclear Dna ◽

Sequence Data ◽

Evolutionary Patterns ◽

Dna Sequence Data ◽

Hawaiian Honeycreepers ◽

Mtdna Introgression

Natural selection plays a fundamental role in the ecological theory of adaptive radiation. A prediction of this theory is the convergent evolution of traits in lineages experiencing similar environments. The Hawaiian honeycreepers are a spectacular example of adaptive radiation and may demonstrate convergence, but uncertainty about phylogenetic relationships within the group has made it difficult to assess such evolutionary patterns. We examine the phylogenetic relationships of the Hawaii creeper ( Oreomystis mana ), a bird that in a suite of morphological, ecological and behavioural traits closely resembles the Kauai creeper ( Oreomystis bairdi ), but whose mitochondrial DNA (mtDNA) and osteology suggest a relationship with the amakihis ( Hemignathus in part) and akepas ( Loxops ). We analysed nuclear DNA sequence data from 11 relevant honeycreeper taxa and one outgroup to test whether the character contradiction results from historical hybridization and mtDNA introgression, or convergent evolution. We found no evidence of past hybridization, a phenomenon that remains undocumented in Hawaiian honeycreepers, and confirmed mtDNA and osteological evidence that the Hawaii creeper is most closely related to the amakihis and akepas. Thus, the morphological, ecological and behavioural similarities between the evolutionarily distant Hawaii and Kauai creepers represent an extreme example of convergent evolution and demonstrate how natural selection can lead to repeatable evolutionary outcomes.

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“Finding Garrett”

The American Biology Teacher ◽

10.1525/abt.2015.77.8.7 ◽

2015 ◽

Vol 77 (8) ◽

pp. 608-612

Author(s):

Madeline K. Strom ◽

Kathleen A. Carroll ◽

Garrett Davis ◽

William Hultman ◽

Tess Kosycarz ◽

...

Keyword(s):

High School ◽

Natural Selection ◽

Phenotypic Plasticity ◽

Convergent Evolution ◽

Divergent Evolution ◽

Fitness Consequences ◽

Learning Game ◽

Evolution Of Communication ◽

The Common ◽

Essential Resource

Natural selection is a mechanism of evolution that leads to adaptations in species or populations. Phenotypes confer habitat-specific fitness consequences, which could lead to the evolution of similar strategies (convergence) or different strategies (divergence) within and across species. The evolution of communication is an example of convergent evolution in many cases. We describe a learning game that simulates the emergence of language and highlights differences between convergent and divergent evolution. With minor modifications, this game can also be used to illustrate phenotypic plasticity. During three preliminary trials, high school and university students representing different species developed novel strategies (languages) to solve the common problem of finding “Garrett,” a student who mimicked an essential resource. Naturally, there was a range of complexity and diversity among the strategies that emerged. We describe how the game can help illustrate evolutionary principles such as adaptation and natural selection.

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Constraints in cancer evolution

Biochemical Society Transactions ◽

10.1042/bst20160229 ◽

2017 ◽

Vol 45 (1) ◽

pp. 1-13 ◽

Cited By ~ 17

Author(s):

Subramanian Venkatesan ◽

Nicolai J. Birkbak ◽

Charles Swanton

Keyword(s):

Natural Selection ◽

Genome Sequencing ◽

Convergent Evolution ◽

Parallel Evolution ◽

Survival Outcomes ◽

Next Generation ◽

Cancer Evolution ◽

Therapeutic Approaches ◽

Biological Impact ◽

Intratumour Heterogeneity

Next-generation deep genome sequencing has only recently allowed us to quantitatively dissect the extent of heterogeneity within a tumour, resolving patterns of cancer evolution. Intratumour heterogeneity and natural selection contribute to resistance to anticancer therapies in the advanced setting. Recent evidence has also revealed that cancer evolution might be constrained. In this review, we discuss the origins of intratumour heterogeneity and subsequently focus on constraints imposed upon cancer evolution. The presence of (1) parallel evolution, (2) convergent evolution and (3) the biological impact of acquiring mutations in specific orders suggest that cancer evolution may be exploitable. These constraints on cancer evolution may help us identify cancer evolutionary rule books, which could eventually inform both diagnostic and therapeutic approaches to improve survival outcomes.

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Biophysical basis for convergent evolution of two veil-forming microbes

Royal Society Open Science ◽

10.1098/rsos.150437 ◽

2015 ◽

Vol 2 (11) ◽

pp. 150437 ◽

Cited By ~ 8

Author(s):

Alexander P. Petroff ◽

Alexis L. Pasulka ◽

Nadine Soplop ◽

Xiao-Lun Wu ◽

Albert Libchaber

Keyword(s):

Diffusion Coefficient ◽

Natural Selection ◽

Convergent Evolution ◽

Chemical Diffusion ◽

Diffusion Limitation ◽

Stagnant Water ◽

Order Of Magnitude ◽

Physical Limitations ◽

Sulfur Oxidizing ◽

Diffusion Coefficient Of Oxygen

Microbes living in stagnant water typically rely on chemical diffusion to draw nutrients from their environment. The sulfur-oxidizing bacterium Thiovulum majus and the ciliate Uronemella have independently evolved the ability to form a ‘veil’, a centimetre-scale mucous sheet on which cells organize to produce a macroscopic flow. This flow pulls nutrients through the community an order of magnitude faster than diffusion. To understand how natural selection led these microbes to evolve this collective behaviour, we connect the physical limitations acting on individual cells to the cell traits. We show how diffusion limitation and viscous dissipation have led individual T. majus and Uronemella cells to display two similar characteristics. Both of these cells exert a force of approximately 40 pN on the water and attach to boundaries by means of a mucous stalk. We show how the diffusion coefficient of oxygen in water and the viscosity of water define the force the cells must exert. We then show how the hydrodynamics of filter-feeding orient a microbe normal to the surface to which it attaches. Finally, we combine these results with new observations of veil formation and a review of veil dynamics to compare the collective dynamics of these microbes. We conclude that this convergent evolution is a reflection of similar physical limitations imposed by diffusion and viscosity acting on individual cells.

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Unmatched level of molecular convergence among deeply divergent complex multicellular fungi

10.1101/549758 ◽

2019 ◽

Cited By ~ 1

Author(s):

Zsolt Merényi ◽

Arun N. Prasanna ◽

Wang Zheng ◽

Károly Kovács ◽

Botond Hegedüs ◽

...

Keyword(s):

Natural Selection ◽

Convergent Evolution ◽

Selection Pressures ◽

Evolutionary Trajectories ◽

Repeated Evolution ◽

Selection Limit ◽

Fungal Genomes ◽

Coding Capacity ◽

Molecular Convergence

AbstractConvergent evolution is pervasive in nature, but it is poorly understood how various constraints and natural selection limit the diversity of evolvable phenotypes. Here, we report that, despite >650 million years of divergence, the same genes have repeatedly been co-opted for the development of complex multicellularity in the two largest clades of fungi—the Ascomycota and Basidiomycota. Co-opted genes have undergone duplications in both clades, resulting in >81% convergence across shared multicellularity-related families. This convergence is coupled with a rich repertoire of multicellularity-related genes in ancestors that predate complex multicellular fungi, suggesting that the coding capacity of early fungal genomes was well suited for the repeated evolution of complex multicellularity. Our work suggests that evolution may be predictable not only when organisms are closely related or are under similar selection pressures, but also if the genome biases the potential evolutionary trajectories organisms can take, even across large phylogenetic distances.

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Variation in tail morphology across urban and forest populations of the crested anole (Anolis cristatellus)

Biological Journal of the Linnean Society ◽

10.1093/biolinnean/blz111 ◽

2019 ◽

Vol 128 (3) ◽

pp. 632-644 ◽

Cited By ~ 1

Author(s):

Sofia R Prado-Irwin ◽

Liam J Revell ◽

Kristin M Winchell

Keyword(s):

Puerto Rico ◽

Natural Selection ◽

Functional Significance ◽

Convergent Evolution ◽

Natural Experiment ◽

Caribbean Island ◽

The Caribbean ◽

Selection For ◽

Urban Sites ◽

Shed Light

AbstractAnolis lizards are well known for their specialist ecomorphs characterized by the convergent evolution of suites of traits linked to the use of particular microhabitats. Many of these same traits evolve rapidly in response to novel selection pressures and have been very well studied. In contrast, the tail crest, a feature present in a subset of lineages, has been almost entirely overlooked. Variation in tail crest morphology within and among species remains largely unstudied, as does the function of the trait. Here, we use the natural experiment provided by urbanization to ask whether tail crest size differs between urban and forest populations of the crested anole (Anolis cristatellus) across the Caribbean island of Puerto Rico. We find that tail crest size differs primarily between regions; however, within regions, crests are invariably larger in urban than in forest environments. This difference in size is correlated with the hotter, drier conditions and sparser distribution of perches that typify urban sites, leading to the intriguing possibility that the tail crest might be under differential natural selection for signalling and/or because of the thermoregulatory challenge of urban habitats. Further study is required to shed light on the functional significance and evolution of this under-studied trait.

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