scholarly journals Reproductive Ontogeny and the Evolution of Morphological Diversity in Conifers and Other Plants

2019 ◽  
Vol 59 (3) ◽  
pp. 548-558 ◽  
Author(s):  
A B Leslie ◽  
J M Losada
Keyword(s):  
Morphological Evolution ◽  
Morphological Diversity ◽  
Developmental Rate ◽  
Reproductive Organs ◽  
Developmental Trajectory ◽  
Evolutionary Significance ◽  
Developmental Patterns ◽  
Functional Roles ◽  
Form And Function ◽  
And Function

Abstract Biologists often study morphological evolution through form and function relationships. But biological structures can perform multiple functional roles, complicating efforts to understand the evolutionary significance of any one relationship. Plant reproductive organs perform multiple roles in a sequence, however, which provides a unique opportunity to understand how structures evolve to meet multiple functional demands. Using conifers as a study group, we discuss how a shared developmental trajectory links the performance of sequential functional roles. Variation in development among lineages can underlie morphological diversity; pollination-stage seed cones in Pinaceae conifers function similarly but show diverse forms reflecting differences in developmental rate. As cones develop further, the morphologies that they use to perform later functional roles are influenced by the specific developmental patterns used to meet earlier demands, which may ultimately limit morphological diversity. However, we also show how selective pressures relating to the final functional stage (seed dispersal) may influence cone anatomy and morphology over all previous stages, highlighting the complex linkages among form, function, and development. We end by discussing the potential relationships between functional ontogeny and morphological disparity in plant reproductive structures more broadly, suggesting that the complex functional roles associated with seed plant reproduction probably underlie the high disparity in this group.

hlh-12, a gene that is necessary and sufficient to promote migration of gonadal regulatory cells in C. elegans, evolved within the Caenorhabditis clade

Genetics ◽  
2021 ◽  
Author(s):  
Hana E Littleford ◽  
Karin Kiontke ◽  
David H A Fitch ◽  
Iva Greenwald
Keyword(s):  
Ectopic Expression ◽  
Morphological Diversity ◽  
Nematode Species ◽  
Bhlh Protein ◽  
Vulval Development ◽  
C Elegans ◽  
Form And Function ◽  
Somatic Gonad ◽  
And Function ◽  
Necessary And Sufficient

Abstract Specialized cells of the somatic gonad primordium of nematodes play important roles in the final form and function of the mature gonad. C. elegans hermaphrodites are somatic females that have a two-armed, U-shaped gonad that connects to the vulva at the midbody. The outgrowth of each gonad arm from the somatic gonad primordium is led by two female Distal Tip Cells (fDTC), while the Anchor Cell (AC) remains stationary and central to coordinate uterine and vulval development. The bHLH protein HLH-2 and its dimerization partners LIN-32 and HLH-12 had previously been shown to be required for fDTC specification. Here, we show that ectopic expression of both HLH-12 and LIN-32 in cells with AC potential transiently transforms them into fDTC-like cells. Furthermore, hlh-12 was known to be required for the fDTCs to sustain gonad arm outgrowth. Here, we show that ectopic expression of HLH-12 in the normally stationary AC causes displacement from its normal position, and that displacement likely results from activation of the leader program of fDTCs because it requires genes necessary for gonad arm outgrowth. Thus, HLH-12 is both necessary and sufficient to promote gonadal regulatory cell migration. As differences in female gonadal morphology of different nematode species reflect differences in the fate or migratory properties of the fDTCs or of the AC, we hypothesized that evolutionary changes in the expression of hlh-12 may underlie evolution of such morphological diversity. However, we were unable to identify an hlh-12 ortholog outside of Caenorhabditis. Instead, by performing a comprehensive phylogenetic analysis of all Class II bHLH proteins in multiple nematode species, we found that HLH-12 evolved within the Caenorhabditis clade, possibly by duplicative transposition of hlh-10. Our analysis suggests that control of gene regulatory hierarchies for gonadogenesis can be remarkably plastic during evolution without adverse phenotypic consequence.

scholarly journals An integrative method for testing form–function linkages and reconstructed evolutionary pathways of masticatory specialization

2015 ◽  
Vol 12 (107) ◽  
pp. 20150184 ◽  
Author(s):  
Z. Jack Tseng ◽  
John J. Flynn
Keyword(s):  
Mechanical Properties ◽  
Morphological Evolution ◽  
Integrative Approach ◽  
Deep Time ◽  
Integrate Form ◽  
Functional Changes ◽  
Form And Function ◽  
Form Function ◽  
Evolutionary Pathways ◽  
And Function

Morphology serves as a ubiquitous proxy in macroevolutionary studies to identify potential adaptive processes and patterns. Inferences of functional significance of phenotypes or their evolution are overwhelmingly based on data from living taxa. Yet, correspondence between form and function has been tested in only a few model species, and those linkages are highly complex. The lack of explicit methodologies to integrate form and function analyses within a deep-time and phylogenetic context weakens inferences of adaptive morphological evolution, by invoking but not testing form–function linkages. Here, we provide a novel approach to test mechanical properties at reconstructed ancestral nodes/taxa and the strength and direction of evolutionary pathways in feeding biomechanics, in a case study of carnivorous mammals. Using biomechanical profile comparisons that provide functional signals for the separation of feeding morphologies, we demonstrate, using experimental optimization criteria on estimation of strength and direction of functional changes on a phylogeny, that convergence in mechanical properties and degree of evolutionary optimization can be decoupled. This integrative approach is broadly applicable to other clades, by using quantitative data and model-based tests to evaluate interpretations of function from morphology and functional explanations for observed macroevolutionary pathways.

Shifting functional roles and the evolution of conifer pollen-producing and seed-producing cones

Paleobiology ◽  
2011 ◽  
Vol 37 (4) ◽  
pp. 587-602 ◽  
Author(s):  
Andrew B. Leslie
Keyword(s):  
Biotic Interactions ◽  
Morphological Diversity ◽  
Reproductive Organs ◽  
Sensu Stricto ◽  
Morphological Data ◽  
Strong Interactions ◽  
Geologic History ◽  
Functional Roles ◽  
Primary Driver ◽  
Reproductive Evolution

Exploring patterns in the evolution of seed plant reproductive morphology within a functional context offers a framework in which to identify and evaluate factors that potentially drive reproductive evolution. Conifers are a particularly useful group for studies of this kind because they have a long geologic history and their reproductive organs are borne on separate structures with discrete functions. Multivariate analysis of morphological data collected from pollen-producing and seed-producing cones of Paleozoic, Mesozoic, and extant conifer species shows that seed cones underwent a significant expansion of morphological diversity that began during the Early-Middle Jurassic and has continued into the present day. In contrast, pollen cones show significantly lower levels of morphological diversity and exhibit similar basic morphologies throughout conifer evolutionary history. The increase in seed cone diversity through time is primarily the result of two novel structural and organizational features that evolved independently in different conifer families during the Mesozoic: robust, tightly packed cones in members of Araucariaceae, Cupressaceae sensu lato, and Pinaceae, and highly reduced, fleshy cones or solitary seeds in Podocarpaceae, Taxaceae, and some members of Cupressaceae sensu stricto. In extant conifers, these cone morphologies are associated with species that have strong interactions with vertebrate seed predators, seed dispersers, or a combination of both. This suggests that increases in the strength and complexity of biotic interactions in the Jurassic and Cretaceous were a primary driver of conifer reproductive evolution, and that patterns of character evolution relate to the increasing importance of cone tissue in seed protection and seed dispersal through time.

Form and function: structural analysis in evolutionary morphology

Paleobiology ◽  
1981 ◽  
Vol 7 (4) ◽  
pp. 430-442 ◽  
Author(s):  
George V. Lauder
Keyword(s):  
Structural Complexity ◽  
Morphological Diversity ◽  
Structural Features ◽  
Constrained Systems ◽  
Hierarchical Organization ◽  
Evolutionary Morphology ◽  
Form And Function ◽  
Historical Factors ◽  
Functional Patterns ◽  
And Function

A theoretical approach to the analysis of historical factors (Raup 1972) in evolutionary morphology is presented which addresses transformational hypotheses about structural systems. This (structural) approach to testing historical hypotheses about phylogenetic constraints on form and function and structural and functional versatility involves (1) the reconstruction of nested sets of structural features in monophyletic taxa, (2) the use of general or emergent organizational properties of structural and functional systems (as opposed to uniquely derived morphological features), and (3) the comparative examination of the consequences for structural and functional diversity of these general features in related monophyletic taxa.Three examples of emergent organizational properties are considered: structural complexity, repetition of parts, and the decoupling of primitively constrained systems. Two classes of hypotheses about the evolution of design are proposed. Transformational hypotheses concern historical pathways of change in form as a consequence of general organizational features which are primitive for a lineage. Relational hypotheses involve correlations between structure-function networks primitive for a clade and morphological diversity both between and within terminal taxa. To the extent that transformational and relational hypotheses about form are corroborated, they provide evidence of underlying regularity in the transformation of organic design that may be a consequence of the hierarchical organization of structural and functional patterns in organisms.

Form and function of the glycocalyx on free cell surfaces

1974 ◽  
Vol 268 (891) ◽  
pp. 55-66 ◽  
Keyword(s):  
Free Cell ◽  
Surface Coat ◽  
Cell Surfaces ◽  
Cell Coat ◽  
Fresh Tissue ◽  
Functional Roles ◽  
Form And Function ◽  
Freeze Etching ◽  
Coat Layer ◽  
And Function

Selected examples of the glycocalyx or cell coat on rickettsiae, bacteria, amoebae, sea-urchin eggs and the cat intestinal microvilli are illustrated and their functional roles are discussed. The differences in the form of various surface coats are noted; while many surface components are truely extraneous expendable coatings, others are so firmly attached that they seem to be a permanent part of the cell. The fuzzy surface coat on the cat intestinal microvilli have been considered in some detail and some new observations on the form of the glycocalyx are presented. The enteric surface coat is not readily visualized in fractured surface replicas of glycerinated tissue but fixed cells frozen in distilled water when replicated after freeze-etching reveal a flamboyant array of a filamentous meshwork attached to the microvilli. This fuzzy coat layer is at least twice as thick in the freeze-etched preparations when compared to thin sectioned material. Fresh tissue frozen without fixation or glycerin treatment did not have a thick fuzzy coat. In its place a thin amorphous blanket-like layer was found.

scholarly journals The Form and Function of PIEZO2

2021 ◽  
Vol 90 (1) ◽  
pp. 507-534
Author(s):  
Marcin Szczot ◽  
Alec R. Nickolls ◽  
Ruby M. Lam ◽  
Alexander T. Chesler
Keyword(s):  
Shear Stress ◽  
Ion Channels ◽  
Molecular Level ◽  
Sensory Biology ◽  
Mechanical Stimuli ◽  
Functional Roles ◽  
Form And Function ◽  
The Past ◽  
And Function ◽  
Sense Of Touch

Mechanosensation is the ability to detect dynamic mechanical stimuli (e.g., pressure, stretch, and shear stress) and is essential for a wide variety of processes, including our sense of touch on the skin. How touch is detected and transduced at the molecular level has proved to be one of the great mysteries of sensory biology. A major breakthrough occurred in 2010 with the discovery of a family of mechanically gated ion channels that were coined PIEZOs. The last 10 years of investigation have provided a wealth of information about the functional roles and mechanisms of these molecules. Here we focus on PIEZO2, one of the two PIEZO proteins found in humans and other mammals. We review how work at the molecular, cellular, and systems levels over the past decade has transformed our understanding of touch and led to unexpected insights into other types of mechanosensation beyond the skin.

scholarly journals Ecomorphology of Neotropical Electric Fishes: An Integrative Approach to Testing the Relationships between Form, Function, and Trophic Ecology

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
K M Evans ◽  
L Y Kim ◽  
B A Schubert ◽  
J S Albert
Keyword(s):  
Resource Utilization ◽  
Trophic Ecology ◽  
Morphological Evolution ◽  
Trophic Levels ◽  
Integrative Approach ◽  
Form And Function ◽  
Form Function ◽  
Electric Fishes ◽  
And Function ◽  
The Relationship

SynopsisThe relationship between form and function is thought to play an integral role in structuring broad-scale patterns of morphological evolution and resource utilization. In ecomorphological studies, mechanical performance is widely understood to constrain the evolution of form and function. However, the relationship between form, function, and resource utilization is less clear. Additionally, seasonal fluctuations in resource availability may further complicate patterns of resource use. How organisms cope with these complexities, and the effect of these factors on broadscale patterns of morphological evolution is also poorly understood. Here we use three-dimensional geometric morphometrics, biomechanics, stable isotope analysis, and gut-content analysis to study trophic evolution in a clade of riverine-adapted electric fishes from a region with high seasonal variability; the Amazon River. We find significant and phylogenetically structured relationships among measures of trophic ecology and skull shape. We also recover a significant relationship between the mechanical advantage of the mandible and trophic position, where species feeding at higher trophic levels have narrower jaws with lower mechanical advantages, and species feeding at lower trophic levels have deeper jaws with higher mechanical advantages. Our results indicate that selection is driving the evolution of mandible shape and performance toward specialization on different trophic ecologies.

scholarly journals Microbiomes In Natura : Importance of Invertebrates in Understanding the Natural Variety of Animal-Microbe Interactions

mSystems ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Jillian M. Petersen ◽  
Jay Osvatic
Keyword(s):  
Human Life ◽  
Diverse Range ◽  
Functional Roles ◽  
Form And Function ◽  
Group Interest ◽  
Invertebrate Animals ◽  
Microbe Interactions ◽  
Almost All ◽  
And Function ◽  
Development And Evolution

ABSTRACT Animals evolved in a world teeming with microbes, which play pivotal roles in their health, development, and evolution. Although the overwhelming majority of living animals are invertebrates, the minority of “microbiome” studies focus on this group. Interest in invertebrate-microbe interactions is 2-fold—a range of immune components are conserved across almost all animal (including human) life, and their functional roles may be conserved. Thus, understanding cross talk between microbes and invertebrate animals can lead to insights of broader relevance. Invertebrates offer unique opportunities to “eavesdrop” on intricate host-microbe conversations because they tend to associate with fewer microbes. On the other hand, considering the vast diversity of form and function that has evolved in the invertebrates, they likely evolved an equally diverse range of ways to interact with beneficial microbes. We have investigated only a few of these interactions in detail; thus, there is still great potential for fundamentally new discoveries.

scholarly journals Nuclear actin: to polymerize or not to polymerize

2006 ◽  
Vol 172 (4) ◽  
pp. 495-496 ◽  
Author(s):  
Wilma A. Hofmann ◽  
Primal de Lanerolle
Keyword(s):  
Structural Properties ◽  
Fluorescence Recovery After Photobleaching ◽  
Fluorescence Recovery ◽  
Nuclear Actin ◽  
Functional Roles ◽  
Form And Function ◽  
And Function

The form and function of actin in the nucleus have been enigmatic for over 30 years. Recently actin has been assigned numerous functional roles in the nucleus, but its form remains a mystery. The intricate relationship between actin form and function in the cytoplasm implies that understanding the structural properties of nuclear actin is elementary to fully understanding its function. In this issue, McDonald et al. (p. 541) use fluorescence recovery after photobleaching (FRAP) to tackle the question of whether nuclear actin exists as monomers or polymers.

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