Do phosphorus requirements for RNA limit genome size in crustacean zooplankton?

Genome ◽  
2008 ◽  
Vol 51 (9) ◽  
pp. 685-691 ◽  
Author(s):  
Dag O. Hessen ◽  
Marc Ventura ◽  
James J. Elser
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Body Size ◽  
Genome Size ◽  
Growth Rates ◽  
Life History Strategies ◽  
Crustacean Zooplankton ◽  
Limited Growth ◽  
P Deficiency ◽  
Small Genome

As for most other organisms, genome size in zooplankton differs widely. This may have a range of consequences for growth rate, development, and life history strategies, yet the causes of this pronounced variability are not settled. Here we propose that small genome size may be an evolutionary consequence of phosphorus (P) allocation from DNA to RNA under P deficiency. To test this hypothesis we have compared the two major groups of zooplankton, copepods and cladocerans, that have overlapping niches and body size. Relative to the cladocerans, copepods have a more complex life history and a lower mass-specific P content, while cladocerans tend to have higher P and RNA contents and higher specific growth rates and frequently experience P-limited growth, likely due to a shortage of P for ribosome synthesis. Cladocerans also generally have smaller genomes than copepods (1C = 0.17–0.63 pg DNA·cell–1 vs. 1C = 0.10–10 pg DNA·cell–1). Furthermore, cladocerans have a higher slope of the relationship of body size with DNA content (1.5 vs. 0.28 in copepods) and present almost 15-fold higher RNA:DNA ratios (24.8 in cladocerans vs. 1.6 in copepods). Hence, small genome size in cladocerans could reflect an evolutionary pressure towards “efficient” genomes to conserve a key element needed to maximize growth rate. We do not claim that this is a universal cause of genome size variability, but propose that streamlining of genomes could be related to P conservation rather than energy conservation. This could be relevant for a range of organisms that may suffer P-limited growth rates.

scholarly journals Ontogenetic changes in the elemental composition and stoichiometry of marine copepods with different life history strategies

2020 ◽  
Vol 42 (3) ◽  
pp. 320-333 ◽  
Author(s):  
Enric Saiz ◽  
Kaiene Griffell ◽  
Albert Calbet
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Elemental Composition ◽  
Growth Rates ◽  
Stoichiometric Composition ◽  
Maximum Growth ◽  
Life History Strategies ◽  
Ontogenetic Variation ◽  
Ontogenetic Changes ◽  
P Content

Abstract We describe the ontogenetic variation in elemental and stoichiometric composition of two copepod species with very contrasted life history patterns, the calanoid Paracartia grani and the cyclopoid Oithona davisae. The first species is a broadcasting, highly productive copepod, whereas the latter is an egg-carrying copepod, much less productive. We reared cultures of both species under conditions of excess food and analyzed their C, N and P composition, and their molar ratios, along development. Both species differed on their specific P content, whereas the specific C and N content were similar. As expected, the specific P content of P. grani was higher, resulting in lower C:P and N:P ratios. Furthermore, we compared our elemental composition data with previously reported stage-specific (nauplii and adult female) maximum growth rates of these two species. We found that for O. davisae, the ontogenetic variation in specific P content agreed with the reported differences in growth rate along development; however, in the case of P. grani, in which juvenile and adult maximum growth rates are similar, the variations in specific P content along development did not reflect the growth rate pattern.

scholarly journals Scaling of growth rate and mortality with size and its consequence on size spectra of natural microphytoplankton assemblages in the East China Sea

2013 ◽  
Vol 10 (8) ◽  
pp. 5267-5280 ◽  
Author(s):  
F. H. Chang ◽  
E. C. Marquis ◽  
C. W. Chang ◽  
G. C. Gong ◽  
C. H. Hsieh
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Growth Rates ◽  
Specific Growth ◽  
Size Structure ◽  
Scaling Exponent ◽  
The East China Sea ◽  
Size Category ◽  
Grazing Mortality ◽  
Specific Growth Rates

Abstract. Allometric scaling of body size versus growth rate and mortality has been suggested to be a universal macroecological pattern, as described by the metabolic theory of ecology (MTE). However, whether such scaling generally holds in natural assemblages remains debated. Here, we test the hypothesis that the size-specific growth rate and grazing mortality scale with the body size with an exponent of −1/4 after temperature correction, as MTE predicts. To do so, we couple a dilution experiment with the FlowCAM imaging system to obtain size-specific growth rates and grazing mortality of natural microphytoplankton assemblages in the East China Sea. This novel approach allows us to achieve highly resolved size-specific measurements that would be very difficult to obtain in traditional size-fractionated measurements using filters. Our results do not support the MTE prediction. On average, the size-specific growth rates and grazing mortality scale almost isometrically with body size (with scaling exponent ∼0.1). However, this finding contains high uncertainty, as the size-scaling exponent varies substantially among assemblages. The fact that size-scaling exponent varies among assemblages prompts us to further investigate how the variation of size-specific growth rate and grazing mortality can interact to determine the microphytoplankton size structure, described by normalized biomass size spectrum (NBSS), among assemblages. We test whether the variation of microphytoplankton NBSS slopes is determined by (1) differential grazing mortality of small versus large individuals, (2) differential growth rate of small versus large individuals, or (3) combinations of these scenarios. Our results indicate that the ratio of the grazing mortality of the large size category to that of the small size category best explains the variation of NBSS slopes across environments, suggesting that higher grazing mortality of large microphytoplankton may release the small phytoplankton from grazing, which in turn leads to a steeper NBSS slope. This study contributes to understanding the relative importance of bottom-up versus top-down control in shaping microphytoplankton size structure.

Inheritance of geographic variation in body size, and countergradient variation in growth rates, in the southern brown bandicoot Isoodon obesulus.

2000 ◽  
Vol 22 (1) ◽  
pp. 9 ◽  
Author(s):  
ML Hale
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Body Size ◽  
Geographic Variation ◽  
Growth Rates ◽  
Habitat Type ◽  
Adaptive Divergence ◽  
Common Environment ◽  
Countergradient Variation ◽  
Large Animals

The inheritance of geographic variation in body size in the southern brown bandicoot (Isoodon obesulus) was investigated through a common-environment crossbreeding experiment. The geographic variation in body size is related to habitat type, suggesting that it may be adaptive. Adults from two locations in Western Australia, Perth (large animals) and Albany (small animals), were collected and offspring from both hybrid and non-hybrid matings were reared under controlled conditions. All four variables examined (head length, pes length, ear length and body weight) were found to possess a large genetic component, supporting the interpretation that the geographic variation in size is adaptive. The three length variables initially showed additive genetic variation, although the variation in body weight displayed dominance. Genetically controlled differences in growth rate were also detected, with the smaller animals, found in the relatively poorer environment, possessing the faster intrinsic growth rate. Thus, not only does there appear to be adaptive divergence in initial body size, but the countergradient variation in growth rates provides additional evidence for adaptive divergence in this species.

Growth ecology of the tree lizard Urosaurus bicarinatus (Squamata: Phrynosomatidae), in a tropical dry forest of the Chamela Region, Mexico

2016 ◽  
Vol 66 (2) ◽  
pp. 189-199 ◽  
Author(s):  
Aurelio Ramírez-Bautista ◽  
Uriel Hernández-Salinas ◽  
J. Gastón Zamora-Abrego
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Growth Rates ◽  
Average Rate ◽  
Growth Patterns ◽  
Dry Forest ◽  
Von Bertalanffy ◽  
Mexican Pacific ◽  
Males And Females ◽  
Tree Lizard

Determination of growth rate provides an important component of an organism’s life history, making estimations of size at maturity, survival rate, and longevity possible. Here, we report on growth rate of males and females of the tropical tree lizard Urosaurus bicarinatus, in a seasonal environment in the state of Jalisco on the Mexican Pacific Coast. We calculated body growth rates and fitted these to the Von Bertalanffy, the logistic-by-length, and the logistic-by-weight growth models. The Von Bertalanffy model provided the best fit, and we used it to analyze the growth pattern. Males and females did not differ in estimated asymptotic size and other characteristic growth parameters. Estimated growth curve predicted an age at maturity of 38 mm SVL on 120 days for males, and 40 mm SVL on 170 days for females. On the basis of the similarities in the growth rates between the sexes, comparisons were made between seasons, and we found that the average rate of growth was slightly, albeit insignificantly, higher in the rainy season than in the dry season. The similarities in the growth patterns for the sexes of this species might be indicative of variance in its life history traits (e.g., fecundity, egg size) compared to those of other populations of this species and other species of this genus; therefore, it is important to document interpopulation differences to understand the evolutionary changes that have led to optimal adaptation in a particular environment more accurately.

Incubation temperature and clutch effects on initial body sizes and growth rates in green iguana hatchlings (Iguana iguana)

2017 ◽  
Vol 67 (3-4) ◽  
pp. 239-249 ◽  
Author(s):  
Yuleimis T. Martínez-Caballero ◽  
Brian C. Bock ◽  
Isabel Pérez ◽  
Ángela M. Ortega-León ◽  
Vivian P. Páez
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Growth Rates ◽  
Egg Size ◽  
Incubation Temperature ◽  
Size Variation ◽  
Early Growth ◽  
Rate Variation ◽  
Body Sizes ◽  
Green Iguanas

Large initial body size and rapid early growth rate are important in many species, both because predation rates decline as individuals grow and because females that attain a larger adult body size are more fecund. To identify possible factors contributing to size and growth rate variation in hatchling green iguanas, we artificially incubated six clutches at three constant temperatures to test for effects of incubation temperature and/or clutch effects on initial size and growth rate. Higher incubation temperatures resulted in significantly shorter incubation periods but did not influence initial body size. There were significant differences among clutches in egg size, and also in initial hatchling body size, even after correcting for differences in egg size among clutches. A subset of hatchlings from each nest was reared in semi-natural conditions for four months, with individuals from the high incubation temperature condition exhibiting the slowest longer-term growth rates. No clutch effects were detected in the growth rate analyses. The observed variation in early growth rate of juvenile iguanas seems to be selectively important and this variation may be due in part to the conditions the eggs experience during incubation, but clutch effects in this study were limited to egg size and initial hatchling body size variation, but were not found for subsequent growth rates.

Attained Size and Growth Rate of Female Volleyball Players between 9 and 13 Years of Age

1994 ◽  
Vol 6 (3) ◽  
pp. 257-266 ◽  
Author(s):  
Robert M. Malina
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Growth Rates ◽  
Growth Status ◽  
School Year ◽  
Body Weights ◽  
Volleyball Players ◽  
Tall Girls ◽  
Accelerated Growth ◽  
Average Body

The growth status and rate of a mixed-longitudinal sample (N = 19) of female volleyball players 9–13 years of age were compared to reference data for the general population. The athletes were measured at the beginning and end of the school year. Growth rates in stature and weight adjusted to 6-month intervals were calculated. The results indicate mean statures that are above U.S. reference medians and mean weights that are near the medians (i.e., tall girls with average body weights). Estimated half-year growth rates in stature and weight from 10.0–13.0 years closely match the respective medians of the Fels longitudinal study. The data thus suggest that the larger body size of young volleyball players is not a function of accelerated growth rate during these early adolescent ages and, thus, not due to earlier maturation; body size is likely genotypic and probably reflects selection at relatively young ages for the size demands of the sport.

Trait-Based Approach to Fish Ecology

2019 ◽  
pp. 150-160
Author(s):  
Ken H. Andersen
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Life History Strategy ◽  
Somatic Growth ◽  
Population Level ◽  
Historical Background ◽  
Life History Strategies ◽  
Asymptotic Size ◽  
Current State ◽  
Investment In Reproduction

This chapter proposes a shortlist of fish “master” traits and connects these traits to classic life-history strategy thinking. First, it sets the historical background for the current state-of-the-art thinking about fish life history strategies. From there, the chapter explains that the main axes of variation between fish species can be captured by three traits: the asymptotic size; the growth rate coefficient; and the adult–offspring mass ratio strategy. Together, these three traits determine the central demographic parameters: somatic growth rate, investment in reproduction, age at maturation, survival to maturation, mortality, and so on, and from there follows population-level quantities like population growth rate, population structure, fitness, and selection responses. The chapter concludes with a reflection on the trait-based approach and compares it to other methods of assessment.

scholarly journals Cannibalism by damselflies increases with rising temperature

2017 ◽  
Vol 13 (5) ◽  
pp. 20170175 ◽  
Author(s):  
Denon Start ◽  
Devin Kirk ◽  
Dylan Shea ◽  
Benjamin Gilbert
Keyword(s):  
Climate Change ◽  
Life History ◽  
Body Size ◽  
Growth Rates ◽  
Effect Of Temperature ◽  
Intraspecific Interactions ◽  
Life History Stages ◽  
Consumption Rates ◽  
Increased Activity ◽  
Antagonistic Interactions

Trophic interactions are likely to change under climate warming. These interactions can be altered directly by changing consumption rates, or indirectly by altering growth rates and size asymmetries among individuals that in turn affect feeding. Understanding these processes is particularly important for intraspecific interactions, as direct and indirect changes may exacerbate antagonistic interactions. We examined the effect of temperature on activity rate, growth and intraspecific size asymmetries, and how these temperature dependencies affected cannibalism in Lestes congener , a damselfly with marked intraspecific variation in size. Temperature increased activity rates and exacerbated differences in body size by increasing growth rates. Increased activity and changes in body size interacted to increase cannibalism at higher temperatures. We argue that our results are likely to be general to species with life-history stages that vary in their temperature dependencies, and that the effects of climate change on communities may depend on the temperature dependencies of intraspecific interactions.

The life history, nymphal growth rates, and feeding habits of Siphlonisca aerodromia Needham (Ephemeroptera: Siphlonuridae) in Maine

1986 ◽  
Vol 64 (2) ◽  
pp. 427-430 ◽  
Author(s):  
K. Elizabeth Gibbs ◽  
Terry M. Mingo
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Sex Ratio ◽  
Growth Rates ◽  
Feeding Habits ◽  
Main Channel ◽  
Head Width ◽  
Snow Melt ◽  
Animal Material ◽  
Nymphal Growth

Siphlonisca aerodromia Needham has a univoltine life history in Maine. Adults emerge in late May or early June. Each female contains about 394 large (0.46 mm long) eggs covered with coiled fibers that anchor the eggs to the substrate. Eggs are deposited in the main channel of the stream and small nymphs appear in January. Nymphal growth rate (GHW) was expressed as a percent per day increase in head width. Initially nymphs feed on detritus and grow slowly (GHW = 0.28–0.79) at water temperatures near 0 °C. Following snow melt, the nymphs move into the adjacent Carex floodplain. Here, water temperature increases, animal material, in the form of mayfly nymphs, becomes increasingly common in the diet, and growth rate increases (GHW = 2.13–2.89). The sex ratio of nymphs collected in May and June was 1:1.8 (male:female).

Sign in / Sign up

Export Citation Format

Share Document