scholarly journals The ectodermal placodes: a dysfunctional family

2001 ◽  
Vol 356 (1414) ◽  
pp. 1655-1660 ◽  
Author(s):  
Jo Begbie ◽  
Anthony Graham
Keyword(s):  
Early Development ◽  
Evolutionary History ◽  
Sensory Systems ◽  
Dysfunctional Family ◽  
Single Entity ◽  
Embryonic Ectoderm ◽  
Development And Evolution

The ectodermal placodes are focal thickenings of the cranial embryonic ectoderm that contribute extensively to the cranial sensory systems of the vertebrates. The ectodermal placodes have long been thought of as representing a coherent group, which share a developmental and evolutionary history. However, it is now becoming clear that there are substantial differences between the placodes with respect to their early development, their induction and their evolution. Indeed, it is now hard to consider the ectodermal placodes as a single entity. Rather, they fall into a number of distinct classes and it is within each of these that the members share a common development and evolution.

Phylogenetic evidence for independent origins of GDF1 and GDF3 genes in amphibians and mammals

2018 ◽  
Author(s):  
Juan C. Opazo ◽  
Kattina Zavala
Keyword(s):  
Growth Factor ◽  
Early Development ◽  
Evolutionary History ◽  
Transforming Growth Factor ◽  
Ancestral Gene ◽  
Differentiation Factors ◽  
Duplication Events ◽  
Independent Duplication ◽  
History Of ◽  
Early Developmental

AbstractGrowth differentiation factors 1 (GDF1) and 3 (GDF3) are members of the transforming growth factor superfamily (TGF-β) that is involved in fundamental early-developmental processes that are conserved across vertebrates. The evolutionary history of these genes is still under debate due to ambiguous definitions of homologous relationships among vertebrates. Thus, the goal of this study was to unravel the evolution of the GDF1 and GDF3 genes of vertebrates, emphasizing the understanding of homologous relationships and their evolutionary origin. Surprisingly, our results revealed that the GDF1 and GDF3 genes found in amphibians and mammals are the products of independent duplication events of an ancestral gene in the ancestor of each of these lineages. The main implication of this result is that the GDF1 and GDF3 genes of amphibians and mammals are not 1:1 orthologs. In other words, genes that participate in fundamental processes during early development have been reinvented two independent times during the evolutionary history of tetrapods.

Development and evolution of the gynoecium in Myrteae (Myrtaceae)

2014 ◽  
Vol 62 (4) ◽  
pp. 335 ◽  
Author(s):  
Rafael R. Pimentel ◽  
Natália P. Barreira ◽  
Diego P. Spala ◽  
Nathane B. Cardim ◽  
Marcelo C. Souza ◽  
...  
Keyword(s):  
Evolutionary History ◽  
Floral Anatomy ◽  
Structural Diversity ◽  
Morphological Characters ◽  
Fleshy Fruit ◽  
South American ◽  
Transmission Electron ◽  
History Of ◽  
Ovule Number ◽  
Development And Evolution

Characters of the gynoecium are considered potentially significant for the systematics of Myrtaceae. However, only two such characters – ovule number and placentation – have been addressed from an evolutionary perspective. Colleter presence in flowers is a synapomorphy of Myrtales; however, no morphological and histochemical descriptions of such structures have been done in Myrtaceae. Here we analysed the ontogeny and anatomy of the gynoecium combined with the ontogeny, anatomy, ultrastructure, and histochemistry of the colleters to study the evolution of these characters and map their states in the Myrteae phylogenetic tree. Our findings may help elucidate the evolutionary history of this tribe of fleshy-fruit producers so important towards maintaining ecological balance in the rainforest. Floral anatomy and ontogeny were analysed using light microscopy. Colleter samples were processed using standard methods for light and transmission electron microscopy. The main metabolites in colleters were detected via histochemistry. To map character states the program Mesquite version 2.71 was used. The morphological characters of the South American Myrteae here analysed provided an overview of the evolution of gynoecium – with cauline or carpellate placenta – and of colleters, as well as synapomorphies for the clades Plinia + Myrcia and Eugenia + Pimenta. The presence of two integuments in the ovules associated with sclereids and colleters in the gynoecium and the young fleshy fruit assures the efficient dispersal of their seeds. Our findings regarding gynoecium structural diversity of the tribe Myrteae give a new insight on their morphologically uniform flowers.

scholarly journals Phylostratigraphic profiles reveal a deep evolutionary history of the vertebrate head sensory systems

2013 ◽  
Vol 10 (1) ◽  
pp. 18 ◽  
Author(s):  
Martin Sebastijan Šestak ◽  
Vedran Božičević ◽  
Robert Bakarić ◽  
Vedran Dunjko ◽  
Tomislav Domazet-Lošo
Keyword(s):  
Evolutionary History ◽  
Sensory Systems ◽  
History Of

The Use and Non-Use of the Human Nature Concept by Evolutionary Biologists

2018 ◽  
Author(s):  
Peter J. Richerson
Keyword(s):  
Human Nature ◽  
Early Development ◽  
Evolutionary History ◽  
Modern Synthesis ◽  
First Year ◽  
Human Culture ◽  
Infancy And Childhood ◽  
First Year Of Life

A number of prominent modern evolutionists embraced ‘human nature’, signalling their commitment to the Modern Synthesis. Their claim is that for most of our evolutionary history, culture was of little importance, and that genes, not culture, controlled early development. More recently, cultural evolutionists have argued that culture and reason were present deep in the Homo lineage, and that the ability to learn socially develops in the first year of life. Thus, it is reasonable to think that genes and culture coevolved in the evolutionary past, and that they codevelop in infancy and childhood. Human nature theorists seek to deny this claim, while at the same time trying in various ways to make room for human culture and reason. I argue here that they are unsuccessful in their attempts.

Material for a Synthesis

2003 ◽  
Author(s):  
Mary Jane West-Eberhard
Keyword(s):  
Early Development ◽  
Evolutionary Theory ◽  
Environmental Influence ◽  
Phenotypic Flexibility ◽  
Immature Stages ◽  
Larval Stages ◽  
Key Concepts ◽  
Adaptive Radiations ◽  
Development And Evolution

The inconsistencies discussed in chapter 1 point toward two fundamental problems in need of solution: how to relate the environmental influence inherent in phenotype development to the genetic emphasis of evolutionary theory—Lewontin’s dilemma—and how to view the diverse phenomena of plasticity and development so as to illuminate evolutionary thinking in new ways—Wallace’s challenge. This chapter briefly describes some important, previously recognized connections among phenotypic flexibility, development, and evolution. It then defines key concepts for the chapters that follow. Important contributions toward a synthesis of development and evolution have accumulated over a period of many years. Some insights appear repeatedly in that cycle of inspiration and amnesia that characterizes important discoveries ahead of their times (for a concise review, see Hall, 1992, pp. 171-174). Some of these insights deal with the phenomenology of development and evolution—evidence that certain behavioral and developmental phenomena have influenced evolution in particular groups or in particular ways. These ideas, long familiar to evolutionary biologists, are the starting points for any attempt at a modern synthesis. Each of them will reappear again in later chapters. It does not require great sophistication in biology to realize that juveniles and adults have distinctive, divergent adaptations. Familiar extreme examples are the caterpillar and the butterfly, the tadpole and the frog. In such metamorphosing species, the juvenile has a dramatically different morphology, behavior, and ecology from that of the adult. Some hypermetamorphic insects show a striking series of differently specialized larval stages, and it is probably true of most organisms that juveniles and adults have different, evolved characteristics appropriate to their different niches, if for no other reason than the different requirements for dispersal, respiration, feeding, and defense that confront individuals of differing size (Schmidt-Nielsen, 1984; see also McKinney and McNamara, 1991). As a corrolary of this, different life stages evolve semi-independently. Thus, immature stages may evolve and diversify, undergoing their own adaptive radiations. Many authors have been impressed with the conservatism of certain aspects of early development.

The ‘Vocal Brain’

2018 ◽  
pp. 36-60
Author(s):  
Pascal Belin
Keyword(s):  
Prefrontal Cortex ◽  
Early Development ◽  
Temporal Lobe ◽  
Evolutionary History ◽  
Functional Organization ◽  
Relevant Information ◽  
Large Set ◽  
Core Network ◽  
Voice Detection ◽  
Types Of Information

Voice cognition—the set of abilities to extract diverse types of information in voices—is supported in our brain by a large set of distributed neural areas. This ‘vocal brain’ is constituted of a core network of voice-sensitive areas in the temporal lobe, the temporal voice areas (TVAs), connected to an extended network of extra-temporal areas with significant voice sensitivity including the amygdala and inferior prefrontal cortex bilaterally. The TVAs are likely performing voice detection and ‘structural encoding’ based on internal voice templates, as a preliminary computational stage necessary prior to analysis of goal-relevant information in the extended network. Despite its early development and long evolutionary history, the vocal brain remains poorly understood and much work remains ahead for a better understanding of its detailed functional organization.

scholarly journals Evolution of ruminant headgear: a review

2011 ◽  
Vol 278 (1720) ◽  
pp. 2857-2865 ◽  
Author(s):  
Edward Byrd Davis ◽  
Katherine A. Brakora ◽  
Andrew H. Lee
Keyword(s):  
Regenerative Medicine ◽  
Early Development ◽  
Histological Study ◽  
Organismal Biology ◽  
Multiple Origins ◽  
Pronghorn Antelope ◽  
Integrative Study ◽  
Single Versus ◽  
Development And Evolution ◽  
Biomedical Fields

The horns, ossicones and antlers of ruminants are familiar and diverse examples of cranial appendages. We collectively term ruminant cranial appendages ‘headgear’; this includes four extant forms: antlers (in cervids), horns (in bovids), pronghorns (in pronghorn antelope) and ossicones (in giraffids). Headgear evolution remains an open and intriguing question because phylogenies (molecular and morphological), adult headgear structure and headgear development (where data are available) all suggest different pictures of ruminant evolution. We discuss what is known about the evolution of headgear, including the evidence motivating previous hypotheses of single versus multiple origins, and the implications of recent phylogenetic revisions for these hypotheses. Inclusion of developmental data is critical for progress on the question of headgear evolution, and we synthesize the scattered literature on this front. The areas most in need of attention are early development in general; pronghorn and ossicone development in particular; and histological study of fossil forms of headgear. An integrative study of headgear development and evolution may have ramifications beyond the fields of systematics and evolution. Researchers in organismal biology, as well as those in biomedical fields investigating skin, bone and regenerative medicine, may all benefit from insights produced by this line of research.

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