scholarly journals Delayed differentiation of epidermal cells walls can underlie pedomorphosis in plants: the case of pedomorphic petals in the hummingbird-pollinated Caiophora hibiscifolia (Loasaceae, subfam. Loasoideae) species

EvoDevo ◽  
2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Marina M. Strelin ◽  
Eduardo E. Zattara ◽  
Kristian Ullrich ◽  
Mareike Schallenberg-Rüdinger ◽  
Stefan Rensing

Abstract Background Understanding the relationship between macroevolutionary diversity and variation in organism development is an important goal of evolutionary biology. Variation in the morphology of several plant and animal lineages is attributed to pedomorphosis, a case of heterochrony, where an ancestral juvenile shape is retained in an adult descendant. Pedomorphosis facilitated morphological adaptation in different plant lineages, but its cellular and molecular basis needs further exploration. Plant development differs from animal development in that cells are enclosed by cell walls and do not migrate. Moreover, in many plant lineages, the differentiated epidermis of leaves, and leaf-derived structures, such as petals, limits organ growth. We, therefore, proposed that pedomorphosis in leaves, and in leaf-derived structures, results from delayed differentiation of epidermal cells with respect to reproductive maturity. This idea was explored for petal evolution, given the importance of corolla morphology for angiosperm reproductive success. Results By comparing cell morphology and transcriptional profiles between 5 mm flower buds and mature flowers of an entomophile and an ornitophile Loasoideae species (a lineage that experienced transitions from bee- to hummingbird-pollination), we show that evolution of pedomorphic petals of the ornithophile species likely involved delayed differentiation of epidermal cells with respect to flower maturity. We also found that developmental mechanisms other than pedomorphosis might have contributed to evolution of corolla morphology. Conclusions Our results highlight a need for considering alternatives to the flower-centric perspective when studying the origin of variation in flower morphology, as this can be generated by developmental processes that are also shared with leaves. Graphical Abstract

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ryo Matsuzaki ◽  
Shigekatsu Suzuki ◽  
Haruyo Yamaguchi ◽  
Masanobu Kawachi ◽  
Yu Kanesaki ◽  
...  

Abstract Background Pyrenoids are protein microcompartments composed mainly of Rubisco that are localized in the chloroplasts of many photosynthetic organisms. Pyrenoids contribute to the CO2-concentrating mechanism. This organelle has been lost many times during algal/plant evolution, including with the origin of land plants. The molecular basis of the evolutionary loss of pyrenoids is a major topic in evolutionary biology. Recently, it was hypothesized that pyrenoid formation is controlled by the hydrophobicity of the two helices on the surface of the Rubisco small subunit (RBCS), but the relationship between hydrophobicity and pyrenoid loss during the evolution of closely related algal/plant lineages has not been examined. Here, we focused on, the Reticulata group of the unicellular green algal genus Chloromonas, within which pyrenoids are present in some species, although they are absent in the closely related species. Results Based on de novo transcriptome analysis and Sanger sequencing of cloned reverse transcription-polymerase chain reaction products, rbcS sequences were determined from 11 strains of two pyrenoid-lacking and three pyrenoid-containing species of the Reticulata group. We found that the hydrophobicity of the RBCS helices was roughly correlated with the presence or absence of pyrenoids within the Reticulata group and that a decrease in the hydrophobicity of the RBCS helices may have primarily caused pyrenoid loss during the evolution of this group. Conclusions Although we suggest that the observed correlation may only exist for the Reticulata group, this is still an interesting study that provides novel insight into a potential mechanism determining initial evolutionary steps of gain and loss of the pyrenoid.


2020 ◽  
Author(s):  
Jean-François Lemaître ◽  
Benjamin Rey ◽  
Jean-Michel Gaillard ◽  
Corinne Régis ◽  
Emmanuelle Gilot ◽  
...  

AbstractDNA methylation-based biomarkers of aging (epigenetic clocks) promise to lead to new insights in the evolutionary biology of ageing. Relatively little is known about how the natural environment affects epigenetic aging effects in wild species. In this study, we took advantage of a unique long-term (>40 years) longitudinal monitoring of individual roe deer (Capreolus capreolus) living in two wild populations (Chizé and Trois Fontaines, France) facing different ecological contexts to investigate the relationship between chronological age and levels of DNA methylation (DNAm). We generated novel DNA methylation data from n=90 blood samples using a custom methylation array (HorvathMammalMethylChip40). We present three DNA methylation-based estimators of age (DNAm or epigenetic age), which were trained in males, females, and both sexes combined. We investigated how sex differences influenced the relationship between DNAm age and chronological age through the use of sex-specific epigenetic clocks. Our results highlight that both populations and sex influence the epigenetic age, with the bias toward a stronger male average age acceleration (i.e. differences between epigenetic age and chronological ages) particularly pronounced in the population facing harsh environmental conditions. Further, we identify the main sites of epigenetic alteration that have distinct aging patterns across the two sexes. These findings open the door to promising avenues of research at the crossroad of evolutionary biology and biogerontology.


2020 ◽  
Vol 16 (2) ◽  
Author(s):  
Gentur Agustinus Naru

Although there have been many studies regarding sensationalism on television, there have not been enough studies to explain why sensational news always attracts viewers' attention regardless of space or time difference. Encouraged by this background, this research tries to answer the question, "What makes sensational news interesting to television viewers?" Inspired by a biological evolutionary perspective, this article formulates a hypothesis that reads, "Sensationalism can draw the attention of the audience because sensational news arouses the most basic instincts of humans, namely the mode of survival (Gurven, 2017)". In this view, the model has become inherent in humans as a result of the evolutionary process. In other words, this hypothesis also believes that audience interest in sensational news is universal rather than contextual.   This article explores a variety of literature in biology, psychology, and communication to try to answer that hypothesis. In order to that, this article is divided into three main sections. We will first explore the history of sensational journalism on television to show the historicity of sensational topics and techniques on television. Second, we will demonstrate the philosophical roots of an evolutionary biology view that explains the relationship between information stimuli and the workings of the human brain and the basic instincts we have carried since evolution thousands of years ago. Finally, we will show studies that prove empirically how news patterns (both sensational topics and production formats) impact viewing interest.


Author(s):  
Tim Lewens

Students of the natural world have long remarked on the fact that animals and plants are well suited to the demands of their environments. ‘Adaptation’, as it is used in modern biology, can name both the process by which organisms acquire this functional match, and the products of that process. Eyes, wings, beaks, camouflaging skin pigmentation and so forth, are all ‘adaptations’ in this second sense. Modern biological orthodoxy follows Darwin in giving a central role to natural selection in explaining the production of adaptations such as these. This much is uncontroversial. But a number of more contentious conceptual questions are raised when we look in more detail at the relationship between natural selection and adaptation. One of these questions concerns how we should define adaptation. It is tempting to characterize adaptations as functional traits – eyes are for seeing, large beaks are for cracking tough seed-casings. This in turn has led many commentators in biology and philosophy to define adaptations as those traits which have been shaped by natural selection for their respective tasks. Others – especially biologists – have complained that such a definition trivializes Darwin’s claim that natural selection explains adaptation. This claim was meant to be an important discovery, not a definitional consequence of the meaning of ‘adaptation’. These worries naturally lead on to the issues of how natural selection itself is to be understood, how it is meant to explain adaptation, and how it should be distinguished from other important evolutionary processes. These topics have a historical dimension: is Darwin’s understanding of natural selection, and its relationship to adaptation, the same as that of today’s evolutionary biology? Textbook presentations often say yes, and this is surely legitimate if we make the comparison in broad terms. But differences emerge when we look in more detail. Darwin, for example, seems to make the ‘struggle for existence’ an essential element of natural selection. It is not clear whether this is the case in modern presentations. And Darwin’s presentation is largely neutral on the inheritance mechanism that accounts for parent/offspring resemblance, while modern presentations sometimes insist that natural selection always implies a genetic underpinning to inheritance.


Bothalia ◽  
2000 ◽  
Vol 30 (1) ◽  
pp. 69-86 ◽  
Author(s):  
C. L. Bredenkamp ◽  
A. E. Van Wyk

Epidermal features were studied in all 17 species of Passerina, a genus endemic to southern Africa. Leaves in Passerina are inversely ericoid, the adaxial surface concave and the abaxial surface convex. Leaves are inversely dorsiventral and epistomatic. The adaxial epidermis is villous, with unicellular, uniseriate trichomes and relatively small thin-walled cells, promoting flexibility of leaf margins owing to turgor changes. In common with many other Thymelaeaceae, abaxial epidermal cells are large and tanniniferous with mucilaginous cell walls. The cuticle is adaxially thin, but abaxially well devel­oped, probably enabling the leaf to restrict water loss and to tolerate high light intensity and UV-B radiation. Epicuticular waxes, present in all species, comprise both soft and plate waxes. Epidermal structure proves to be taxonomically impor­tant at family, genus and species levels. Interspecific differences include arrangement of stomata and presence or absence of abaxial epidermal hair. Other diagnostic characters of the abaxial epidermal cells are arrangement,size and shape, cutic- ular ornamentation and presence or absence of wax platelets. Two groups of species on the basis of abaxial epidermal cell orientation are recognised. Many leaf epidermal features in Passerina are interpreted as structural adaptations to the Mediterranean climate of the Cape.


Author(s):  
Yumi Henmi ◽  
Gyo Itani

Abstract Many alpheid shrimps live symbiotically on the body surface or inside the bodies of other invertebrates, while others use burrows made by other animals. The burrow symbiosis of alpheid shrimps is poorly studied in the context of ecology, probably because the cryptic infaunal nature of the relationship is hard to observe. The limited knowledge of the pattern of burrow use by alpheid shrimps leaves a gap in our understanding of their evolutionary history. We described and compared the behavior of Stenalpheops anacanthus  Miya, 1997 and Athanas japonicus  Kubo, 1936, two alpheid species living symbiotically in the burrows of the same host, Upogebia yokoyai  Makarov, 1938. We found that both alpheid species used U. yokoyai burrows in aquaria, but their burrow use patterns were quite different. The average time taken for S. anacanthus to enter the burrow for the first time was much shorter (1 min) than that of A. japonicus (13 min). Subsequently, S. anacanthus made longer use of the burrow (80% of the observation period) than A. japonicus (49%). The tail-first exit frequency, which may indicate a sudden expulsion from the burrow by the host, was more frequent in A. japonicus (25%) than in S. anacanthus (7%). Such differences could be attributed to the nature of the symbiotic relationship, obligate in S. anacanthus but facultative in A. japonicus. Because of the diversity of symbiotic lifestyles, there is considerable potential to study the ecology and evolutionary biology of burrow-symbiotic alpheids further.


2001 ◽  
Vol 14 (2) ◽  
pp. 175 ◽  
Author(s):  
Andrew C. Rozefelds ◽  
Richard W. Barnes ◽  
Belinda Pellow

The vegetative and reproductive morphology of Vesselowskya Pampanini, southern marara, is described and illustrated in detail. The variation within V. rubifolia (F.Muell.) Pampanini sens. lat. is shown to be greater than has previously been recognised, with the differences identified supporting the recognition of a new segregate species, V. venusta Rozefelds, R.W.Barnes and Pellow sp. nov. Vesselowskya venusta occurs in the Barrington Tops Plateau of New South Wales and differs from V. rubifolia in possessing hairs on the abaxial surface of the sepals and lacking both a prominent distal connective protrusion on the anthers and colleters at the base of the stipules. The two Vesselowskya species are dioecious with a vestigial ovary in staminate flowers and reduced stamens in pistillate flowers. Dioecy is more pronounced in Vesselowskya, than in some Weinmannia species, and in both genera is expressed through reduction in the size of the ovaries in staminate flowers, and stamens in pistillate flowers. Vesselowskya shares with the other genera in the tribe Cunonieae (Pancheria, Weinmannia and Cunonia), a central column in the fruits, and Cunonia-type stipules, but differs from these genera in having valvate aestivation, digitate leaves, craspedodromous secondary venation with secondary veins terminating at a tooth, tuft domatia along the midrib, adaxial epidermal cells with strongly sinuous cell walls and the absence of hydathodes.


Parasitology ◽  
1974 ◽  
Vol 68 (2) ◽  
pp. 161-172 ◽  
Author(s):  
Graham C. Kearn

When eggs of the monogenean parasiteEntobdella hippoglossi, from the skin of the halibut (Hippoglossus hippoglossus), are incubated at 7 °C in alternating 12 h periods of dim blue light (intensity about 3 nW/cm2) and darkness, free-swimming larvae are recovered mostly at the end of the first 2 h of the period of darkness. Larvae do not emerge in significant numbers when the eggs are mechanically disturbed during the light or dark periods, or when the eggs are placed in shadow for periods of 5–25 min during the illumination period. The treatment of fully developed eggs with washings from halibut or from sole or with halibut skin mucus failed to produce hatching.The free-swimming life of the larvae at 7 °C is in excess of 24 h and within 4 h of hatching at 4 °C some larvae are able to attach themselves to halibut skin and shed their ciliated epidermal cells.The relationship between the hatching pattern of the eggs of the parasite and the behaviour of the halibut is discussed.


F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 776 ◽  
Author(s):  
Jos Kramer ◽  
Joël Meunier

Kin selection and multilevel selection are two major frameworks in evolutionary biology that aim at explaining the evolution of social behaviors. However, the relationship between these two theories has been plagued by controversy for almost half a century and debates about their relevance and usefulness in explaining social evolution seem to rekindle at regular intervals. Here, we first provide a concise introduction into the kin selection and multilevel selection theories and shed light onto the roots of the controversy surrounding them. We then review two major aspects of the current debate: the presumed formal equivalency of the two theories and the question whether group selection can lead to group adaptation. We conclude by arguing that the two theories can offer complementary approaches to the study of social evolution: kin selection approaches usually focus on the identification of optimal phenotypes and thus on the endresult of a selection process, whereas multilevel selection approaches focus on the ongoing selection process itself. The two theories thus provide different perspectives that might be fruitfully combined to promote our understanding of the evolution in group-structured populations.


2019 ◽  
Vol 1 (1) ◽  
Author(s):  
F El Moustaid ◽  
S J Lane ◽  
I T Moore ◽  
L R Johnson

Abstract The Cort-Fitness Hypothesis has generated much interest from investigators integrating field endocrinology with evolutionary biology, ecology, and conservation. The hypothesis was developed to test the assumption that if glucocorticoid levels increase with environmental challenges and fitness decreases with environmental challenges, then there should be a negative relationship between baseline glucocorticoid levels and fitness. Indeed, studies across diverse taxa have found that the relationship between baseline glucocorticoid levels and fitness are not consistent: some studies show a positive relationship, others negative, and some show no correlation. Hence, a deeper understanding of the mechanisms underlying the relationship between baseline glucocorticoid levels, environmental challenges, and fitness is needed. We propose a mathematical model representing the links between baseline glucocorticoid levels, environmental challenges, and fitness. Our model describes how variation in the predictability and intensity of environmental challenges, reproductive strategies, and fitness metrics can all contribute to the variability observed in empirical tests of the Cort-Fitness Hypothesis. We provide qualitative results showing that much of the inconsistency in previous studies can be explained and we discuss how the model can be used to inform future Cort-Fitness studies.


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