scholarly journals Generation length for mammals

2013 ◽  
Vol 5 ◽  
pp. 89-94 ◽  
Author(s):  
Moreno Di Marco ◽  
Michela Pacifici ◽  
Luca Santini ◽  
Daniele Baisero ◽  
Lucilla Francucci ◽  
...  
Keyword(s):  
Author(s):  
Martin Sheader

Ampelisca tenuicornis Lilljeborg, 1855, is a member of a widely distributed genus of benthic tube-dwelling amphipods. Population studies of A. macrocephala Lilljeborg in the Øresund show it to have a generation length of 2 years (Kanneworff, 1965), and A. vadorum Mills off Massachusetts, U.S.A., produces two generations per year (Mills, 1967). A. brevicornis (Costa) in the Mediterranean breeds throughout the year with a generation time of 5–7 months (Kaim-Malka, 1969), but has only one generation per year in Helgoland Bight (Klein, Rachor & Gerlach, 1975).


2020 ◽  
Author(s):  
Serena Wong ◽  
Jennifer S. Bigman ◽  
Nicholas K. Dulvy

AbstractAll life acquires energy through metabolic processes and that energy is subsequently allocated to life-sustaining functions such as survival, growth, and reproduction. Thus, it has long been assumed that metabolic rate is related to the life history of an organism. Indeed, metabolic rate is commonly believed to set the pace of life by determining where an organism is situated along a fast-slow life history continuum. However, empirical evidence of a relationship between metabolic rate and life histories is lacking, especially for ectothermic organisms. Here, we ask whether three life history traits – maximum body mass, generation length, and growth performance – explain variation in resting metabolic rate (RMR) across fishes. We found that growth performance, which accounts for the trade-off between growth rate and maximum body size, explained variation in RMR, yet maximum body mass and generation length did not. Our results suggest that measures of life history that encompass trade-offs between life history traits, rather than traits in isolation, explain variation in RMR across fishes. Ultimately, understanding the relationship between metabolic rate and life history is crucial to metabolic ecology and has the potential to improve prediction of the ecological risk of data-poor species.


2020 ◽  
Vol 23 ◽  
pp. e01047
Author(s):  
Ru-Yi Yin ◽  
Yun-Chun Ye ◽  
Chris Newman ◽  
Christina D. Buesching ◽  
David W. Macdonald ◽  
...  

Nature ◽  
1977 ◽  
Vol 269 (5626) ◽  
pp. 354-355
Author(s):  
E. J. TODARO ◽  
R. BENVENIFTE

1979 ◽  
Vol 30 (4) ◽  
pp. 767 ◽  
Author(s):  
GL Toll ◽  
JSF Barker

Registrations of animals in 1975 were used in a study of the importance of Imported and Horned animals and of individual herds and animals, the degree of inbreeding and the generation length. Results were compared with an earlier analysis (1960) of the breed, and considered in relation to the prohibition on the importation of ruminant animals into Australia from 1959 to 1969. The rate of increase in inbreeding (0.44% per generation) and the average generation length (5.3 years) have remained relatively stable throughout the breed history in Australia. While there has been some decrease in the emphasis on Imported animals, the breed maintains a high relationship to animals imported since 1930, and six of the 15 important animals (relationship to breed greater than 2.0%) were imported. It is concluded that the importation prohibition has had little effect on the genetic history of the breed, because of line breeding to bulls imported prior to 1959.


1977 ◽  
Vol 24 (1) ◽  
pp. 109-112 ◽  
Author(s):  
J. W. James

SUMMARYThe generation interval may be defined as the mean age of parents of all progeny born, or as the mean age of parents of only those progeny destined to be selected as replacements. If the mean age of parents of replacements is used, selection differentials must be calculated within parental age groups. If the mean age of parents of all progeny born is used, the selection differential contains a component due to disproportionate selection of replacements from different parental age groups.


2021 ◽  
Vol 288 (1953) ◽  
pp. 20210910
Author(s):  
Serena Wong ◽  
Jennifer S. Bigman ◽  
Nicholas K. Dulvy

All life acquires energy through metabolic processes and that energy is subsequently allocated to life-sustaining functions such as survival, growth and reproduction. Thus, it has long been assumed that metabolic rate is related to the life history of an organism. Indeed, metabolic rate is commonly believed to set the pace of life by determining where an organism is situated along a fast–slow life-history continuum. However, empirical evidence of a direct interspecific relationship between metabolic rate and life histories is lacking, especially for ectothermic organisms. Here, we ask whether three life-history traits—maximum body mass, generation length and growth performance—explain variation in resting metabolic rate (RMR) across fishes. We found that growth performance, which accounts for the trade-off between growth rate and maximum body size, explained variation in RMR, yet maximum body mass and generation length did not. Our results suggest that measures of life history that encompass trade-offs between life-history traits, rather than traits in isolation, explain variation in RMR across fishes. Ultimately, understanding the relationship between metabolic rate and life history is crucial to metabolic ecology and has the potential to improve prediction of the ecological risk of data-poor species.


2011 ◽  
Vol 6 (3) ◽  
pp. 729-741
Author(s):  
Marko Porčić

In this paper an attempt is made to estimate the number of figurines which were in "use" in households of the Late Neolithic Vin!a culture. The number of accumulated figurines and houses is used as a starting point. Given the complexities of the settlement dynamic, figurine use and the formation processes of the archaeological record, the ratio of the number of accumulated of figurines to the number of accumulated houses is only an indirect reflection of the systemic number of figurines. Different figurine use scenarios are evaluated in order to see what the result would be. Keeping in mind that the entire analytical procedure is highly speculative and the range of tested models is far from exhaustive, the results suggest that scenarios resting on the assumption that there was a single figurine per household and that the average use-life of the figurine was equal to the average human generation length predict outcomes that are comparable to the actual archaeological situation.


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