Population structure and reproductive biology of peyote (Lophophora diffusa, Cactaceae), a threatened species with pollen limitation1,2

2020 ◽  
Vol 147 (3) ◽  
Author(s):  
María Isabel Briseño-Sánchez ◽  
Concepción Martínez-Peralta ◽  
María C. Mandujano
Keyword(s):  
Population Structure ◽  
Reproductive Biology ◽  
Threatened Species

scholarly journals Population structure and reproductive biology of Metamysidopsis neritica (Crustacea: Mysidacea) in a sand beach in south Brazil

2008 ◽  
Vol 25 (3) ◽  
pp. 403-412 ◽  
Author(s):  
Patrícia Calil ◽  
Carlos A. Borzone
Keyword(s):  
Population Structure ◽  
Reproductive Biology ◽  
Direct Relationship ◽  
Surf Zone ◽  
Population Characteristics ◽  
Egg Volume ◽  
Sand Beach ◽  
The World ◽  
Egg Number ◽  
South Brazil

Mysidacea are common sublittoral crustaceans that inhabit all coasts in the world. In this study, the population characteristics and the reproductive biology of Metamysidopsis neritica Bond-Buckup & Tavares, 1992 were studied in the surf zone of a south Brazilian beach (Atami). Mysids were sampled at monthly intervals from August, 1999 to July, 2000 (total of 29,490 individuals). Individuals were classified into six population categories. The highest abundance occurred in May (8,665) and August (6,415), and lowest in September (336) and December (368). Three main generations were identified, namely the summer, fall and winter generations. The winter generation was the longest (four to five months). The fall generation lasted four months, and the summer one extended from three to four months. Ovigerous females occurred throughout the year, with a greater proportion in July. The number of eggs or larvae varied from one to 16. Weak associations were found between female length and egg number, egg volume, and the number of larvae with and without eyes. Egg volume increased during the coldest season, whereas the smallest values were recorded during summer. These results suggest a possible direct relationship between egg volume and generation longevity.

Reproductive biology and population structure of Potimirim brasiliana Villalobos, 1959 (Decapoda, Atyidae) from a littoral fast-flowing stream, São Paulo State, Brazil

Crustaceana ◽  
2013 ◽  
Vol 86 (1) ◽  
pp. 67-83 ◽  
Author(s):  
Sergio Schwarz Da Rocha ◽  
Roberto Munehisa Shimizu ◽  
Sergio L. De Siqueira Bueno ◽  
Fernando L. Mantelatto
Keyword(s):  
Population Structure ◽  
Reproductive Biology ◽  
Sao Paulo ◽  
São Paulo ◽  
Paulo State ◽  
São Paulo State ◽  
Flowing Stream

Population Structure and Reproductive Biology of Saururus cernuus L. (Saururaceae)

1994 ◽  
Vol 9 (1) ◽  
pp. 47-55 ◽  
Author(s):  
LEONARD B. THIEN ◽  
ERIK G. ELLGAARD ◽  
MARGARET S. DEVALL ◽  
SARA E. ELLGAARD ◽  
PAUL F. RAMP
Keyword(s):  
Population Structure ◽  
Reproductive Biology

Chromosomal changes in vertebrate evolution

1977 ◽  
Vol 199 (1136) ◽  
pp. 377-397 ◽  
Keyword(s):  
Population Structure ◽  
Reproductive Biology ◽  
Chromosome Banding ◽  
Chromosomal Rearrangements ◽  
Chromosomal Polymorphism ◽  
Vertebrate Evolution ◽  
Factors Influencing ◽  
Extant Species ◽  
Chromosomal Changes ◽  
Karyotypic Change

The immense variety of karyotypes found in extant species is unmistakable evidence that the process of evolution is associated with karyotypic change. The question whether the chromosome changes are a cause or a consequence of speciation has been debated intensely for many years and, as is often the case with biological problems, there has been no unequivocal answer. Evolution operates along different lines in different groups of organisms. In animals, reproductive biology and population structure are important factors influencing the rate of karyotypic change. Still, the most extreme chromosomal rearrangements are not necessarily found in the most specialized species. A great number of chromosome banding techniques has made it possible to study chromosomes of vertebrates in great detail. Some applications of these techniques to problems of chromosomal polymorphism in relation to mammalian speciation are presented.

Cryopreservation and other assisted reproductive technologies for the conservation of threatened amphibians and reptiles: bringing the ARTs up to speed

2016 ◽  
Vol 28 (8) ◽  
pp. 1116 ◽  
Author(s):  
John Clulow ◽  
Simon Clulow
Keyword(s):  
Reproductive Biology ◽  
Habitat Loss ◽  
Threatened Species ◽  
Assisted Reproductive Technologies ◽  
Reproductive Technologies ◽  
Proof Of Concept ◽  
End Points ◽  
Biodiversity Crisis ◽  
The Arts ◽  
Future Work

Amphibians and reptiles are experiencing serious declines, with the number of threatened species and extinctions growing rapidly as the modern biodiversity crisis unfolds. For amphibians, the panzootic of chytridiomycosis is a major driver. For reptiles, habitat loss and harvesting from the wild are key threats. Cryopreservation and other assisted reproductive technologies (ARTs) could play a role in slowing the loss of amphibian and reptile biodiversity and managing threatened populations through genome storage and the production of live animals from stored material. These vertebrate classes are at different stages of development in cryopreservation and other ARTs, and each class faces different technical challenges arising from the separate evolutionary end-points of their reproductive biology. For amphibians, the generation of live offspring from cryopreserved spermatozoa has been achieved, but the cryopreservation of oocytes and embryos remains elusive. With reptiles, spermatozoa have been cryopreserved in a few species, but no offspring from cryopreserved spermatozoa have been reported, and the generation of live young from AI has only occurred in a small number of species. Cryopreservation and ARTs are more developed and advanced for amphibians than reptiles. Future work on both groups needs to concentrate on achieving proof of concept examples that demonstrate the use of genome storage and ARTs in successfully recovering threatened species to increase awareness and support for this approach to conservation.

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