scholarly journals A comparative test of the gamete dynamics theory for the evolution of anisogamy in Bryopsidales green algae

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Tatsuya Togashi ◽  
Yusuke Horinouchi ◽  
Geoff A. Parker
Keyword(s):  
Life Cycle ◽  
Green Algae ◽  
Adult Stage ◽  
Male Gamete ◽  
Comparative Test ◽  
Disruptive Selection ◽  
Adult Size ◽  
Male Gametes ◽  
Selection For ◽  
Gamete Size

Gamete dynamics theory proposes that anisogamy arises by disruptive selection for gamete numbers versus gamete size and predicts that female/male gamete size (anisogamy ratio) increases with adult size and complexity. Evidence has been that in volvocine green algae, the anisogamy ratio correlates positively with haploid colony size. However, green algae show notable exceptions. We focus on Bryopsidales green algae. While some taxa have a diplontic life cycle in which a diploid adult (=fully grown) stage arises directly from the zygote, many taxa have a haplodiplontic life cycle in which haploid adults develop indirectly: the zygote first develops into a diploid adult (sporophyte) which later undergoes meiosis and releases zoospores, each growing into a haploid adult gametophyte. Our comparative analyses suggest that, as theory predicts: (i) male gametes are minimized, (ii) female gamete sizes vary, probably optimized by number versus survival as zygotes, and (iii) the anisogamy ratio correlates positively with diploid (but not haploid) stage complexity. However, there was no correlation between the anisogamy ratio and diploid adult stage size. Increased environmental severity (water depth) appears to drive increased diploid adult stage complexity and anisogamy ratio: gamete dynamics theory correctly predicts that anisogamy evolves with the (diploid) stage directly provisioned by the zygote.

scholarly journals Biological aspects of Hylesia metapyrrha (Lepidoptera; Saturniidae; Hemileucinae), in laboratory

2007 ◽  
Vol 67 (1) ◽  
pp. 173-177 ◽  
Author(s):  
A. Specht ◽  
AC. Formentini ◽  
E. Corseuil
Keyword(s):  
Life Cycle ◽  
Incubation Period ◽  
Adult Stage ◽  
Immature Stages ◽  
Average Period ◽  
Development Stages ◽  
Behavioral Aspects ◽  
Biological Aspects ◽  
Guava Leaves

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.

Seedling vigour as a preselection criterion for short juvenile period in olive breeding

2006 ◽  
Vol 57 (4) ◽  
pp. 477 ◽  
Author(s):  
R. De la Rosa ◽  
A. I. Kiran ◽  
D. Barranco ◽  
L. León
Keyword(s):  
Adverse Effects ◽  
Adult Stage ◽  
General Context ◽  
Fruit Traits ◽  
Juvenile Period ◽  
Seedling Vigour ◽  
Breeding Programs ◽  
Early Evaluation ◽  
Selection For ◽  
Olive Breeding

The juvenile period represents a serious impediment in olive breeding programs. Seedlings with long juvenile period are of very low interest for the breeder because their evaluation considerably delays the first stages of the breeding process. For this reason, the influence of seedling vigour (measured as plant height or stem diameter) on the characteristics at the adult stage was studied to establish useful negative preselection criteria on the basis of that relationship. Olive progenies from crosses and open pollinations of 12 different parents carried out in 1998 and 1999 were evaluated in the greenhouse and, afterwards, during the first 3 years of bearing in the open field. The results obtained indicate that early evaluation and selection for juvenile period can be performed at the seedling stage in olive progenies on the basis of vigour measurements. Selection for short juvenile period was valid irrespective of parentage and, therefore, could be efficient in a general context. No relationship between juvenile period and yield or fruit traits was found so that this preselection criterion would have no adverse effects on these characters.

THE IMMATURE STAGES OF PTYCHOPTERA LENIS LENIS (DIPTERA: PTYCHOPTERIDAE) WITH NOTES ON THEIR BIOLOGY

1973 ◽  
Vol 105 (8) ◽  
pp. 1091-1099 ◽  
Author(s):  
I. D. Hodkinson
Keyword(s):  
Life Cycle ◽  
Water Depth ◽  
Adult Stage ◽  
Atmospheric Oxygen ◽  
Adult Emergence ◽  
Fourth Instar ◽  
Immature Stages ◽  
Experimental Conditions ◽  
Marginal Areas ◽  
Pharate Adult

AbstractThe four larval instars and the pupa of Ptychoptera lenis lenis Osten Sacken are described. Instars 2 to 4 are very similar morphologically but instar 1 is markedly different. Both a pharate pupal and a pharate adult stage were observed. Larvae are found in stagnant marginal areas of ponds where water depth does not exceed 4 cm and where benthic deposits of plant detritus exceed 8 cm. Fourth instar larvae, under experimental conditions, survived up to 45 days without contact with atmospheric oxygen but development was arrested. P. lenis has a 1 year life cycle with an extended adult emergence season from late May to the end of July.

Appropriate decision making in energy technology selection for developing countries: The Life Cycle Assessment approach

2021 ◽  
pp. 83-89
Author(s):  
Abeer Ali Khan
Keyword(s):  
Decision Making ◽  
Developing Countries ◽  
Life Cycle Assessment ◽  
Life Cycle ◽  
Technology Selection ◽  
Energy Technology ◽  
High Demand ◽  
Environmentally Conscious ◽  
Assessment Approach ◽  
Selection For

As the high demand of energy of the developing countries is met by importing energy and different energy technology, it has become increasingly necessary to discuss the environmental impacts throughout the life cycle of those technologies and make better decisions. Developed in the late 1960s, Life Cycle Assessment (LCA) has become a wide-ranging tool used to determine impacts of products or systems over several environmental and resource issues. The LCA approach has become more prevalent in research, industry and policy with growing concern for the environment. Therefore, the aim of this paper is to introduce the use of LCA in the decision-making process while selecting an energy technology. In this way, more environmentally conscious decisions will be made as LCAs can provide a better basis for this process.

Larval habitats impose trait-dependent limits on the direction and rate of adult evolution in dragonflies

2021 ◽  
Vol 17 (5) ◽  
pp. 20210023
Author(s):  
Michael P. Moore
Keyword(s):  
Natural Selection ◽  
Comparative Study ◽  
Adult Stage ◽  
Larval Habitat ◽  
Adult Size ◽  
Larval Habitats ◽  
Size Evolution ◽  
Fitness Benefits ◽  
Context Dependent ◽  
Ornament Evolution

Natural selection on juveniles is often invoked as a constraint on adult evolution, but it remains unclear when such restrictions will have their greatest impact. Selection on juveniles could, for example, mainly limit the evolution of adult traits that mostly develop prior to maturity. Alternatively, selection on juveniles might primarily constrain the evolution of adult traits that experience weak or context-dependent selection in the adult stage. Using a comparative study of dragonflies, I tested these hypotheses by examining how a species’ larval habitat was related to the evolution of two adult traits that differ in development and exposure to selection: adult size and male ornamentation. Whereas adult size is fixed at metamorphosis and experiences consistent positive selection in the adult stage, ornaments develop throughout adulthood and provide context-dependent fitness benefits. My results show that species that develop in less stable larval habitats have smaller adult sizes and slower rates of adult size evolution. However, these risky larval habitats do not limit ornament expression or rates of ornament evolution. Selection on juveniles may therefore primarily affect the evolution of adult traits that mostly develop prior to maturity.

Compatibility Analysis of Product Design for Recyclability and Reuse

1994 ◽  
Author(s):  
Patrick Di Marco ◽  
Charles F. Eubanks ◽  
Kos Ishii
Keyword(s):  
Life Cycle ◽  
Cost Function ◽  
Product Design ◽  
Material Selection ◽  
Computer Tool ◽  
Compatibility Analysis ◽  
Life Cycle Design ◽  
Environmentally Responsible ◽  
Qualitative Knowledge ◽  
Selection For

Abstract This paper describes a method for evaluating the compatibility of a product design with respect to end-of-life product retirement issues, particularly recyclability. Designers can affect the ease of recycling in two major areas: 1) ease of disassembly, and 2) material selection for compatibility with recycling methods. The proposed method, called “clumping,” involves specification of the level of disassembly and the compatibility analysis of each remaining clump with the design’s post-life intent; i.e., reuse, remanufacturing, recycling, or disposal. The method uses qualitative knowledge to assign a normalized measure of compatibility to each clump. An empirical cost function maps the measure to an estimated cost to reprocess the product. The method is an integral part of our life-cycle design computer tool that effectively guides engineers to an environmentally responsible product design. A refrigerator in-door ice dispenser serves as an illustrative example.

scholarly journals Chironomidae: Biology, Ecology and Systematics

2021 ◽  
Author(s):  
Zerguine Karima
Keyword(s):  
Life Cycle ◽  
Larval Stage ◽  
Adult Stage ◽  
Aquatic Environments ◽  
Biting Midges ◽  
Important Family ◽  
Theoretical Synthesis ◽  
The Family ◽  
The World ◽  
Holarctic Region

The family of Chironomidae is a group of Diptera insects belonging to the suborder of Nematocera, commonly called “non-biting midges” in the adult stage and “bloodworms” in the larval stage. The Chironomidae are often the most abundant group of macroinvertebrates, in number of species and individuals, encountered in all aquatic environments of freshwater, brackish, terrestrial and even the sea. Likewise, Chironomidae occur in all the continents. The Chironomidae family is divided into 11 sub-families that have diffrent ecological statues. Despite the wealth of data on Chironomidae in the Holarctic region, other parts of the world are poorly studied and few guides to identifying Chironomidae have been produced. This chapter includes a theoretical synthesis on the Chironomidae, it deals with the Biology (life cycle and description of different stages), description of all subfamilies and the ecology of this important family of Diptera.

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