Bridging Darwin's Origin of Species & Wegener's Origin of Continents and Oceans:

2016 ◽  
Vol 78 (1) ◽  
pp. 24-33 ◽  
Author(s):  
Cristina Sousa

The common ancestor and evolution by natural selection, concepts introduced by Charles Darwin, constitute the central core of biology research and education. However, students generally struggle to understand these concepts and commonly form misconceptions about them. To help teachers select the most revelant portions of Darwin's work, I suggest some sentences from On the Origin of Species and briefly discuss their implications. I also suggest a teaching strategy that uses history of science and curriculum crosscutting concepts (cause and effect) that constitute the framework to explain the evolutionary history of ratites (flightless birds) as described by Darwin, starting in the Jurassic, with the breakup of Gondwanaland, as first described by Alfred Wegener in The Origin of Continents and Oceans.

2015 ◽  
Author(s):  
Chan-gyu Yun

In this paper, I comment on Barrett et al. (2015) "Evolution of dinosaur epidermal structures". Though the original authors made some very interesting results, the conclusions made by them are likely influenced by inappropriate or incorrect assumptions such as very little preserved skin fragments represent whole body covering or dinosaurian integumentary structures might represent a degraded collagen fibres. Therefore, their result might represent small size of current datas or preservational bias rather than actual evolutionary history of dinosaurian feathers.


2015 ◽  
Author(s):  
Chan-gyu Yun

In this paper, I comment on Barrett et al. (2015) "Evolution of dinosaur epidermal structures". Though the original authors made some very interesting results, the conclusions made by them are likely influenced by inappropriate or incorrect assumptions such as very little preserved skin fragments represent whole body covering or dinosaurian integumentary structures might represent a degraded collagen fibres. Therefore, their result might represent small size of current datas or preservational bias rather than actual evolutionary history of dinosaurian feathers.


Mammalia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mourad Ahmim ◽  
Hafid Aroudj ◽  
Farouk Aroudj ◽  
Saaid Saidi ◽  
Samir Aroudj

Abstract The common genet (Genetta genetta Linnaeus, 1758) is a rare and protected mammal species in Algeria. We report the first melanistic individual of this species ever recorded in North Africa. Such animals have only been recorded in Spain and Portugal so far. It is unclear why melanistic common genets seem to be so rare in its African range. More research is needed to determine the true occurrence of melanistic individuals, and what the evolutionary history of melanism is in common genets.


2019 ◽  
Author(s):  
Laura Hernández ◽  
Alberto Vicens ◽  
Luis Enrique Eguiarte ◽  
Valeria Souza ◽  
Valerie De Anda ◽  
...  

ABSTRACTDimethylsulfoniopropionate (DMSP), an osmolyte produced by oceanic phytoplankton, is predominantly degraded by bacteria belonging to the Roseobacter lineage and other marine Alphaproteobacteria via DMSP-dependent demethylase A protein (DmdA). To date, the evolutionary history of DmdA gene family is unclear. Some studies indicate a common ancestry between DmdA and GcvT gene families and a co-evolution between Roseobacter and the DMSP-producing-phytoplankton around 250 million years ago (Mya). In this work, we analyzed the evolution of DmdA under three possible evolutionary scenarios: 1) a recent common ancestor of DmdA and GcvT, 2) a coevolution between Roseobacter and the DMSP-producing-phytoplankton, and 3) pre-adapted enzymes to DMSP prior to Roseobacter origin. Our analyses indicate that DmdA is a new gene family originated from GcvT genes by duplication and functional divergence driven by positive selection before a coevolution between Roseobacter and phytoplankton. Our data suggest that Roseobacter acquired dmdA by horizontal gene transfer prior to exposition to an environment with higher DMSP. Here, we propose that the ancestor that carried the DMSP demethylation pathway genes evolved in the Archean, and was exposed to a higher concentration of DMSP in a sulfur rich atmosphere and anoxic ocean, compared to recent Roseobacter ecoparalogs (copies performing the same function under different conditions), which should be adapted to lower concentrations of DMSP.


Heredity ◽  
2002 ◽  
Vol 88 (4) ◽  
pp. 235-242 ◽  
Author(s):  
M Ratkiewicz ◽  
S Fedyk ◽  
A Banaszek ◽  
L Gielly ◽  
W Chȩtnicki ◽  
...  

2020 ◽  
Vol 61 (6) ◽  
pp. 1107-1119
Author(s):  
Jan Kuciński ◽  
Sebastian Chamera ◽  
Aleksandra Kmera ◽  
M Jordan Rowley ◽  
Sho Fujii ◽  
...  

Abstract RNase H1 is an endonuclease specific toward the RNA strand of RNA:DNA hybrids. Members of this protein family are present in most living organisms and are essential for removing RNA that base pairs with DNA. It prevents detrimental effects of RNA:DNA hybrids and is involved in several biological processes. Arabidopsis thaliana has been previously shown to contain three genes encoding RNase H1 proteins that localize to three distinct cellular compartments. We show that these genes originate from two gene duplication events. One occurred in the common ancestor of dicots and produced nuclear and organellar RNase H1 paralogs. Second duplication occurred in the common ancestor of Brassicaceae and produced mitochondrial- and plastid-localized proteins. These proteins have the canonical RNase H1 activity, which requires at least four ribonucleotides for endonucleolytic digestion. Analysis of mutants in the RNase H1 genes revealed that the nuclear RNH1A and mitochondrial RNH1B are dispensable for development under normal growth conditions. However, the presence of at least one organellar RNase H1 (RNH1B or RNH1C) is required for embryonic development. The plastid-localized RNH1C affects plastid DNA copy number and sensitivity to replicative stress. Our results present the evolutionary history of RNH1 proteins in A. thaliana, demonstrate their canonical RNase H1 activity and indicate their role in early embryonic development.


Antiquity ◽  
2009 ◽  
Vol 83 (320) ◽  
pp. 458-461
Author(s):  
Christopher Evans

AbstractWe are grateful to Chris Evans for convening and introducing this imaginative archaeological tribute to the work of Charles Darwin, 150 years after the publication of his On the origin of species – the inspiration for an evolutionary concept of history in so many fields. June 2009 is also the 150th anniversary of a yet more momentous event in the history of archaeology, the endorsement of the antiquity of human tool-making by observations in the Somme gravels. Clive Gamble and Robert Kruszynski reconstruct the occasion and publish the famous axe for the first time. Chris Evans returns to present us with the bitter-sweet spectacle of the Darwin family as excavators and Tim Murray rediscovers a suite of pictures made for John Lubbock which show how prehistoric life was envisaged in polite society at the time. Lastly we are grateful to Colin Renfrew for his own reflections on the anniversary.


2019 ◽  
Vol 28 (6) ◽  
pp. 587-592 ◽  
Author(s):  
Cory J. Clark ◽  
Brittany S. Liu ◽  
Bo M. Winegard ◽  
Peter H. Ditto

Humans evolved in the context of intense intergroup competition, and groups comprised of loyal members more often succeeded than groups comprised of nonloyal members. Therefore, selective pressures have sculpted human minds to be tribal, and group loyalty and concomitant cognitive biases likely exist in all groups. Modern politics is one of the most salient forms of modern coalitional conflict and elicits substantial cognitive biases. The common evolutionary history of liberals and conservatives gives little reason to expect protribe biases to be higher on one side of the political spectrum than the other. This evolutionarily plausible null hypothesis has been supported by recent research. In a recent meta-analysis, liberals and conservatives showed similar levels of partisan bias, and several protribe cognitive tendencies often ascribed to conservatives (e.g., intolerance toward dissimilar other people) were found in similar degrees in liberals. We conclude that tribal bias is a natural and nearly ineradicable feature of human cognition and that no group—not even one’s own—is immune.


2020 ◽  
Vol 12 (11) ◽  
pp. 2107-2124
Author(s):  
Diego Santos-Garcia ◽  
Natividad Mestre-Rincon ◽  
David Ouvrard ◽  
Einat Zchori-Fein ◽  
Shai Morin

Abstract Whiteflies (Hemiptera: Sternorrhyncha: Aleyrodidae) are a superfamily of small phloem-feeding insects. They rely on their primary endosymbionts "Candidatus Portiera aleyrodidarum" to produce essential amino acids not present in their diet. Portiera has been codiverging with whiteflies since their origin and therefore reflects its host’s evolutionary history. Like in most primary endosymbionts, the genome of Portiera stays stable across the Aleyrodidae superfamily after millions of years of codivergence. However, Portiera of the whitefly Bemisia tabaci has lost the ancestral genome order, reflecting a rare event in the endosymbiont evolution: the appearance of genome instability. To gain a better understanding of Portiera genome evolution, identify the time point in which genome instability appeared and contribute to the reconstruction of whitefly phylogeny, we developed a new phylogenetic framework. It targeted five Portiera genes and determined the presence of the DNA polymerase proofreading subunit (dnaQ) gene, previously associated with genome instability, and two alternative gene rearrangements. Our results indicated that Portiera gene sequences provide a robust tool for studying intergenera phylogenetic relationships in whiteflies. Using these new framework, we found that whitefly species from the Singhiella, Aleurolobus, and Bemisia genera form a monophyletic tribe, the Aleurolobini, and that their Portiera exhibit genome instability. This instability likely arose once in the common ancestor of the Aleurolobini tribe (at least 70 Ma), drawing a link between the appearance of genome instability in Portiera and the switch from multibacteriocyte to a single-bacteriocyte mode of inheritance in this tribe.


Sign in / Sign up

Export Citation Format

Share Document