Molluscan Development

1985 ◽  
Vol 13 ◽  
pp. 33-49 ◽  
Author(s):  
David Jablonski

Early ontogeny is still the least well-known part of the molluscan life cycle, despite its unarguable significance in ecology, biogeography, and evolution. The past decade has seen an acceleration in biological research on molluscan embryonic and larval development, and paleontologists have recently begun to explore this field as well. Although the very earliest phases of ontogeny are inaccessible to the paleontologist, a remarkable amount of information can be derived from the preserved details of larval shell morphology. The fossil record thus affords rich opportunities to study directly the development of extinct species, both from a phylogenetic standpoint and for tracing the evolutionary and biogeographic effects of these early stages in life history. Access to long-extinct clades and an ability to document rates and patterns of evolution allow paleontologists to test hypotheses that can be addressed only indirectly using Recent data. Here I will emphasize these paleontological aspects of molluscan development (see also Jablonski and Lutz, 1983); for the more strictly biological aspects of reproduction and embryology, see Giese and Pearse (1977, 1979), Verdonk et al. (1983) and Tompa et al. (1984).

Paleobiology ◽  
1983 ◽  
Vol 9 (3) ◽  
pp. 269-279 ◽  
Author(s):  
Neil H. Landman ◽  
Danny M. Rye ◽  
Kevin L. Shelton

Observations on the morphology of the early whorls of Eutrephoceras dekayi (Morton), a widespread Cretaceous nautilid, are supplemented with oxygen and carbon isotopic analyses (δ18O and δ13C) of the early septa of five well-preserved specimens to help identify the point of hatching on the shell. Septa 4 and 5 are more closely spaced than preceding septa and probably correspond in time of formation with a constriction or first broken aperture on the outer shell one-third whorl forward of the fourth septum. In modern Nautilus, morphologic, isotopic, and observational data suggest that similar features mark hatching. Between the fourth and fifth septa in E. dekayi, δ18O values show a shift of variable magnitude from heavy to lighter values followed by a return to heavier values over the next one to three septa. This isotopic shift is compatible with a hatching interpretation and may be explained as the result of kinetic and equilibrium effects on emergence from an egg capsule.Eutrephoceras dekayi hatched at about 9 mm in diameter, one-third the hatching size of modern Nautilus. Like Nautilus, E. dekayi probably produced few young, all of which were active swimmers at hatching. In contrast, Mesozoic ammonoids produced numerous offspring ranging from 0.5 to 1.5 mm in diameter which may have spent some time in the plankton. These differences in life history may correlate with differences in ecologic specialization, environmental tolerance, and habitat between ammonoids and nautilids and may have contributed to their disparate rates of evolution during the Mesozoic.


2020 ◽  
pp. 1-42
Author(s):  
Louwrens Pieter Snyman ◽  
Michael Ohl ◽  
Christian Walter Werner Pirk ◽  
Catherine Lynne Sole

Adult Mantispidae are general predators of arthropods equipped with raptorial forelegs. The three larval instars display varying degrees of hypermetamorphic ontogeny. The larval stages exhibit a remarkable life history ranging from specialised predators of nest-building hymenopteran larvae and pupa, to specialised predators of spider-eggs, to possible generalist predators of immature insects. Noteworthy advances in our understanding of the biology of Mantispidae has come to light over the past two decades which are compiled and addressed in this review. All interactions of mantispids with other arthropods are tabled and their biology critically discussed and compared to the current classification of the taxon. Additionally, the ambigous systematics within Mantispidae and between Mantispidae and its sister groups, Rhachiberothidae and Berotidae, is reviewed. Considering the biology, systematics, distribution of higher taxonomic levels and the fossil record, the historical biogeography of the group is critically discussed with Gondwana as the epicenter of Mantispidae radiation.


2020 ◽  
Vol 9 (4) ◽  
pp. 157
Author(s):  
NFN SISWANTO ◽  
E. A. WIKARDI ◽  
E. KARMAWATI

<p>Dalam beberapa tahun terakhir tanaman jambu mete di NTB diserang oleh wercng pucuk. yang semula dikenal sebagai Lawana sp. atau L. Candida. Penamaan tersebut tidak tepat karena tidak didukung oleh penelitian taksonomi yang memadai. Penelitian ini bertujuan untuk mengidentifikasi serangga wereng pucuk tersebut berdasarkan ciri morfologi serta mcmpelajari beberapa aspek biologinya. Identiikasi dilakukan di Balai Penelitian Tanaman Rempah dan Obat (Balittro), Bogor dan Pusat Penelitian dan Pengembangan Biologi LIPI, Cibinong dari September - Nopember 2002, sedang pengamatan lapang di lakukan di daerah Lombok, NTB pada tahun 2001-2002. Dai identifikasi terhadap serangga contoh yang diambil dai beberapa lokasi di Lombok, NTB dapat disimpulkan bahwa wereng pucuk jambu mete tersebut adalah Sanurus indecora Jacobi. Beberapa cii utama serangga ini antara lain pada bentuk dan venasi sayap depan (legmen), jumlah spina (duri) lateral pada tibia kaki belakang, bentuk carina pada frons (muka bagian atas) dan bentuk aedeagus (genitalia jantan). Hasil pengamatan di lapangan menunjukkan bahwa daerah sebaran serangga tersebut terdapat di daerah Lombok dan Sumbawa, mempunyai banyak inang antara lain mangga, jeruk, krotalaria, jarak, rambutan, bougcnville dan nangka, siklus hidup 3 -4 minggu, seekor imago mampu meletakkan telur 80 butir atau lebih serta mempunyai beberapa musuh alami antara lain parasitoid telur, Aphanomerus sp. dan jamur entomopatogen, Synnematium sp. dan atau Hirsulella citriformis.</p><p>Kata kunci: Wereng pucuk, jambu mete, Sanurus indecora</p><p> </p><p><strong>ABSTRACT</strong></p><p><strong>Identiication of cashew shoot hopper, S. indecora and its biological aspects</strong></p><p>In the last few years, cashew plantations in West Nusa Tenggara has been attacking by shoot hopper, which formerly known as Lawana sp. or L. Candida. The naming was incorrect as there was not supported by accurate taxonomic study. The research was aimed at identifying the insect based on its morphological characteristics and studying its biological aspects in the ield. Identification was carried out in Balittro (Research Institute for Spice and Medicinal Crops), Bogor and Biological Research and Development Centre LIPI, Cibinong from September Nopember 2002, while ield observation was carried out in Lombok, NTB duing 2001-2002. Identification result showed that the shoot hopper is Sanurus indecora Jacobi. Some important characteristics of the insect arc the form and venation of tegmen, number of metatibial spina, form of carina on the frons and Ihe aedeagus. Results of the ield observation showed that the insect spreads in Lombok and Sumbawa. The alternative host plants are mango, citrus, Crolalaria, Ricmus commums, rambutan, Bougenville and Jackfruit. Its life cycle is 3 -4 weeks, female could lay 80 eggs or more. They have some natural enemies such as egg parasitoid, Aphanomerus sp. and entomopathogen fungi. Synnematium sp. or Hirsulella cilnformts.</p><p>Key words : Shool hopper, Anacardium occidentale. Sanurus indecora</p>


Author(s):  
Charis-Charles Chintiroglou ◽  
Thalia Valkouma ◽  
Michael Culley

This paper discusses a number of biological aspects, concerning a new sea anemone species (Paranemonia vouliagmeniensis Doumenc et al., 1987 ) (Actiniaria: Anthozoa), discovered in Lake Vouliagmeni, near Athens, Greece. The specialized environment of the lake, with elevated and stable temperatures throughout the year, brackish waters and large mineral content presents a very specialized biotope in which Paranemonia wuliagmeniensis is an important member. Certain aspects of its life cycle were investigated, especially population structure, feeding habits and life history. The population was found to be made up of two sub-populations; one established on algae in deeper parts of the lake, and an older one living on gravel in shallower habitats. Feeding preferences depended on the anemone's ability to catch prey, combined with the composition of the prey. The anemone was also found to be viviparous and demonstrated r-characteristics in its life history (short lifespan and large number of embryos).


2020 ◽  
Vol 17 (8) ◽  
pp. 922-945
Author(s):  
Andrés-Felipe Villamizar-Mogotocoro ◽  
Andrés-Felipe León-Rojas ◽  
Juan-Manuel Urbina-González

The five-membered oxacyclic system of furan-2(5H)-ones, commonly named as γ- butenolides or appropriately as Δα,β-butenolides, is of high interest since many studies have proven its bioactivity. During the past few years, Δα,β-butenolides have been important synthetic targets, with several reports of new procedures for their construction. A short compendium of the main different synthetic methodologies focused on the Δα,β-butenolide ring formation, along with selected examples of compounds with relevant biological activities of these promising pharmaceutical entities is presented.


2014 ◽  
Vol 3 (1) ◽  
pp. 70 ◽  
Author(s):  
Marcelo Bern�l ◽  
Rosana Schneider ◽  
�nio Machado

Over the past few decades, conventional agriculture has been facing serious crises caused by numerous factors, including poor soil management and the excessive application of pesticides. Thus, alternative production systems have been developed, including agroforestry systems, especially those that produce both energy and food. The objective of this study was to environmentally evaluate the culture of Aleurites fordii Hemls. (Tung) using the Life Cycle Assessment method with the SimaPro 7.3.2 software. The results revealed that in family farms that use less mechanization to harvest crops, the primary category of environmental impact was land use, which included the removal of animal and vegetable species and ecosystem changes. The full impact of this category was 1741.21 m2yr PDF (potentially disappeared fraction). Subsequently, prognostics were established for the reduction of such impacts, and we conclude that Tung has a high potential for agricultural installation with high responsibility to the environment. Keywords: Environmental factors, Aleurites fordii Hemls, Life Cycle Management, Tung.


2021 ◽  
Vol 13 (14) ◽  
pp. 7939
Author(s):  
Sohani Vihanga Withanage ◽  
Komal Habib

The unprecedented technological development and economic growth over the past two decades has resulted in streams of rapidly growing electronic waste (e-waste) around the world. As the potential source of secondary raw materials including precious and critical materials, e-waste has recently gained significant attention across the board, ranging from governments and industry, to academia and civil society organizations. This paper aims to provide a comprehensive review of the last decade of e-waste literature followed by an in-depth analysis of the application of material flow analysis (MFA) and life cycle assessment (LCA), i.e., two less commonly used strategic tools to guide the relevant stakeholders in efficient management of e-waste. Through a keyword search on two main online search databases, Scopus and Web of Science, 1835 peer-reviewed publications were selected and subjected to a bibliographic network analysis to identify and visualize major research themes across the selected literature. The selected 1835 studies were classified into ten different categories based on research area, such as environmental and human health impacts, recycling and recovery technologies, associated social aspects, etc. With this selected literature in mind, the review process revealed the two least explored research areas over the past decade: MFA and LCA with 33 and 31 studies, respectively. A further in-depth analysis was conducted for these two areas regarding their application to various systems with numerous scopes and different stages of e-waste life cycle. The study provides a detailed discussion regarding their applicability, and highlights challenges and opportunities for further research.


Cells ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 113 ◽  
Author(s):  
Stephanie Maia Acuña ◽  
Lucile Maria Floeter-Winter ◽  
Sandra Marcia Muxel

An inflammatory response is essential for combating invading pathogens. Several effector components, as well as immune cell populations, are involved in mounting an immune response, thereby destroying pathogenic organisms such as bacteria, fungi, viruses, and parasites. In the past decade, microRNAs (miRNAs), a group of noncoding small RNAs, have emerged as functionally significant regulatory molecules with the significant capability of fine-tuning biological processes. The important role of miRNAs in inflammation and immune responses is highlighted by studies in which the regulation of miRNAs in the host was shown to be related to infectious diseases and associated with the eradication or susceptibility of the infection. Here, we review the biological aspects of microRNAs, focusing on their roles as regulators of gene expression during pathogen–host interactions and their implications in the immune response against Leishmania, Trypanosoma, Toxoplasma, and Plasmodium infectious diseases.


2007 ◽  
Vol 67 (1) ◽  
pp. 173-177 ◽  
Author(s):  
A. Specht ◽  
AC. Formentini ◽  
E. Corseuil

The aim of this work was to study biological aspects and the life cycle of Hylesia Metapyrrha in a laboratory. Laboratorial breeding was made at 25 ± 1 °C, 70 ± 10% UR and 14 hours of photophase, feeding the larvae with guava leaves (Psidium guayava L. - Myrtaceae). Time was evaluated on the days of all the development stages; morphometry was evaluated in millimeters and the pupa’s mass in grams. The eggs were disposed in groups and covered by urticating abdominal hair. The incubation period lasted 52 days. The larvae, with gregarious habits, presented background black coloration, yellowish scoli and two orange longitudinal lines above and below the spiracles, during the development which lasted an average period of 74.59 days and went through seven instars. The pre-pupa and the pupa stages lasted on average 8.82 and 50.56 days, respectively; the female pupae presented a duration, weight and size which was significantly bigger. The adult stage lasted on average 5.50 days with periods of pre, post and oviposition of 2.30, 1.90 and 1.00 days, respectively. This study broadens the knowledge of the immature stages, biological, morphological and behavioral aspects, until then restricted to the morphology and to registers of the occurrence of the adult forms.


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