scholarly journals Population dynamics and age-dependent mortality processes in tropical reptiles

2019 ◽  
Author(s):  
Hugo Cayuela ◽  
Godfrey C. Akani ◽  
Emmanuel M. Hema ◽  
Edem A. Eniang ◽  
Nioking Amadi ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Mortality Rate ◽  
Common Phenomenon ◽  
Common Process ◽  
Age Dependent ◽  
Kinixys Erosa ◽  
The Relationship ◽  
Contrast Studies ◽  
Critical Challenge ◽  
Dependent Mortality

AbstractUnderstanding age-dependent mortality processes is a critical challenge for population biologists. Actuarial senescence appears to be a common process across the tree of life. Senescence patterns are highly variable in pluricellular organisms: senescence can be gradual or sharp and its onset may be early or delayed. By contrast, studies revealed that organisms may also not experience senescence at all while others display a “negative senescence”; i.e. a decrease of mortality rate with age. To date, studies on senescence have largely focused on human and other endotherm vertebrates, limiting our understanding of senescence in amniotes as a whole. By contrast, few have examined the diversity of senescence patterns in ectotherm vertebrates as reptiles. Here, we examined population dynamics and age-dependent mortality patterns in three tropical tortoises (Kinixys erosa, Kinixys homeana, Kinixys nogueyi) and snakes (Bitis gabonica, Bitis nasicornis, Causus maculatus). Our study revealed that tortoises ofKinixysgenus had a higher survival and a lower recruitment than snakes of the generaBitisandCausus, indicating that they have a slower life history. Furthermore, we showed that survival more slowly decreased with age in tortoises than in snakes. In addition, we highlighted contrasted patterns of age-dependent mortality in the three genera. InKinixys, the relationship between mortality rate and age was positive and linear, suggesting gradual senescence over tortoise lifetime. By contrast, the relationship between mortality rate and age was negative and sharp inBitisandCausus, possibly due to a “negative senescence” starting early in life. Our study highlighted various age-dependent mortality patterns in tropical reptiles. It also contributed to extend our knowledge of senescence in ectotherm vertebrates whose the demography is still poorly understood. In addition, while negative senescence has never been reported in endotherm vertebrates, our results showed that it can be common phenomenon in ectotherms.

Life history and age-dependent mortality processes in tropical reptiles

2019 ◽  
Author(s):  
Hugo Cayuela ◽  
Godfrey C Akani ◽  
Emmanuel M Hema ◽  
Edem A Eniang ◽  
Nioking Amadi ◽  
...  
Keyword(s):  
Life History ◽  
Mortality Rate ◽  
Tree Of Life ◽  
Common Phenomenon ◽  
Model Species ◽  
Common Process ◽  
Age Dependent ◽  
Kinixys Erosa ◽  
The Relationship ◽  
Dependent Mortality

Abstract Actuarial senescence appears to be a common process, and senescence patterns are highly variable across the tree of life. To date, studies on animal senescence have largely focused on model species, such as as fruit flies, humans and a few other endotherms. In contrast, our knowledge about ageing remains fragmentary in ectotherm vertebrates, such as reptiles. Here, we examined life history and age-dependent mortality patterns in three tropical tortoises (Kinixys erosa, Kinixys homeana and Kinixys nogueyi) and snakes (Bitis gabonica, Bitis nasicornis and Causus maculatus). Our study revealed that tortoises of the genus Kinixys had a higher survival and a lower recruitment than snakes of the genera Bitis and Causus, indicating a slower life history. Furthermore, we confirmed that survival decreased more slowly with age in tortoises than in snakes. In addition, we highlighted contrasting patterns of age-dependent mortality among the three genera. In Kinixys, the relationship between mortality rate and age was positive and linear, suggesting gradual senescence over tortoise lifetime. In contrast, the relationship between mortality rate and age was negative and sharp in Bitis and Causus, possibly owing to a ‘negative senescence’. Our study is one of the few to have examined and compared the demography and age-dependent mortality patterns of tropical reptiles. Among other things, our results suggest that although negative senescence has never been reported in endotherm vertebrates, it could be a common phenomenon in ectotherms.

The Comparison of Susceptibility to SARS-CoV-2 Infection between Pediatric and Adults

2021 ◽  
Author(s):  
Milad Zandi ◽  
Saber Soltani ◽  
Mona Fani ◽  
Haniye Shafipour ◽  
Samaneh Abbasi
Keyword(s):  
Public Health ◽  
Risk Factors ◽  
Mortality Rate ◽  
Age Groups ◽  
Severe Illness ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2 ◽  
The World ◽  
Smoking Susceptibility ◽  
The Relationship

SARS-CoV-2 causes coronavirus disease 2019 (COVID-19) and is responsible for the recent pandemic in the world. It has been recently recognized as a challenge for public health and a significant cause of severe illness in all age groups. Young children and older people are susceptible to SARS-CoV-2 infection. However, children usually present mild symptoms compared to adult patients. The relationship between age, severity, and COVID-19 transmission is compared to determine whether there is any reasonable relationship between age and COVID-19. It should be mentioned that some risk factors may increase the probability of developing severe COVID-19 by advancing age, such as pathophysiological changes in the respiratory system, angiotensin-converting enzyme 2 expression in the nasopharynx, and smoking. Susceptibility to SARS-CoV-2 infection is independent of age, but the mortality rate of COVID-19 depends on age.

scholarly journals Estado Atual de Conhecimento de Dinâmica de Populações

2019 ◽  
Vol 23 (3) ◽  
pp. 256
Author(s):  
Anna Clara Balbina Silva ◽  
Afonso Pelli
Keyword(s):  
Population Dynamics ◽  
Full Text ◽  
Mortality Rates ◽  
Structured Populations ◽  
Exclusion Criteria ◽  
Spatially Structured Populations ◽  
The Subject ◽  
Population Interactions ◽  
Dynamic Population ◽  
Critical Challenge

Compreender os mecanismos que regulam a dinâmica das populações espacialmente estruturadas é um desafio crítico para os ecólogos e gestores de conservação. A dinâmica de populações é um ramo da ecologia que estuda as populações como sistema em atividades, relacionando as influências ambientais com a distribuição e abundância dos indivíduos e suas interações com o ambiente. O presente artigo é uma revisão bibliográfica, com o objetivo de identificar produções científicas relevantes sobre dinâmica populacional. Para isso, foram utilizados periódicos revisados por pares, na base de Periódicos Capes. A pesquisa foi realizada em junho de 2019, utilizando-se as palavras-chave para título contendo: "population dynamics" e no assunto “ecology”, a partir de 2014, quando o texto completo estava disponível. Foram considerados como critérios de exclusão os artigos publicados antes de 2014. Após a leitura dos títulos dos artigos, foram selecionados 34 artigos que foram lidos na íntegra. Em livros disponíveis no acervo da biblioteca da Universidade Federal do Triângulo Mineiro, foram selecionados quatro livros no tema dinâmica populacional. O referencial teórico aborda os aspectos da dinâmica de populações, tabela de vida, formas de crescimento e interações populacionais. Ressalta-se a necessidade de novos estudos que ainda possuem lacunas, que venha complementar e contribuir para o conhecimento de organismos que faltam ou ainda não possuem registros de estudos. Palavras-chave: Taxas de Natalidade e Mortalidade. Atributos Populacionais. Dispersão. AbstractUnderstanding the mechanisms that regulate the dynamics of spatially structured populations is a critical challenge for ecologists and conservation managers. Population dynamics is a branch of ecology that studies populations as a system in activities, relating environmental influences to the individuals’ distribution and abundance and their interactions with the environment. This article is a bibliographic review, aiming to identify relevant scientific productions about population dynamics. Thus. peer-reviewed journals were used in the Capes Periodicals base, the research was conducted in June 2019, using the keywords for title containing "population dynamics" and in the subject "ecology", from 2014, when the full text was available. Exclusion criteria were: articles published before 2014, after reading the article titles, 34 articles were selected that met the initially proposed criteria and were read in full. In books available in the library collection of the Federal University of Triângulo Mineiro, with a search for the dynamic population theme, 4 books were used. The theoretical framework addresses the aspects of population dynamics, life table, forms of growth and population interactions. It is emphasized  the need for further studies that still have gaps, which will complement and contribute to the knowledge of organisms that are missing or do not have study records. Keywords: Birth and Mortality Rates. Population Attributes. Dispersion.

Sign in / Sign up

Export Citation Format

Share Document