Increasing and decreasing functional area of the dentition (FAD) of Mammuthus primigenius

The occlusal morphology and continuous molar replacement in elephants provide a very effective functional area for grinding the biomass that is more or less abrasive. Parts of two subsequent molars contribute to the “functional area of the dentition” (FAD). The FAD size, measured in cm², is associated with age and body size. The FAD stage is indicated by the specific teeth contributing to the FAD and represents the individual age. This study concentrates on Mammuthus primigenius and compares the FAD stages, as derived from growth series, with the fossil Elephas antiquus, as well as the extant Elephas maximus and Loxodonta africana. During the life history of the taxa studied, the functional area increases simultaneously with an increase in body size, but decreases severely in senile age stages. In some senile individuals, the FAD is only about 20–50 % of the mean area of an adult animal. The reduction of the FAD beyond a specific size does not mean an immediate starvation of the animal. The general constitution of the individual and the resources of fat accumulation earlier may support the animal for some time but certainly not over a longer period. Nevertheless, the highly reduced functional area was sufficient to keep the animal alive despite its full adult body mass. A much larger FAD in all adult stages provides the energy requirements needed for all additional life functions including competition and reproduction.     

Growth and Investment in Hominin Life History Evolution: Patterns, Processes, and Outcomes

The transitions from apes to lineages allied to humans are marked by shifts in the allocation of parental effort, associated with discontinuous changes in rates of infant and juvenile growth both prenatally and postnatally. Here, I assess growth and life history characteristics of apes within a general mammalian / primate paradigm, using time and energy expenditure as 2 fundamentals that covary with infant survival and success probabilities. I suggest that these survival probabilities depend on the quality, amount, and timing of parental care allocated to infants. Growth to birth, growth to weaning, and growth to reproductive onset are partitioned as separate periods within a life history on the basis of comparative mammalian data. Growth problems such as sexual dimorphism can be incorporated into an investment perspective by assessing when and how sex-specific parental care affects growth rates and the onset of reproduction. I compare features of the hominoid life history with developmental rates for hominin lineages as seen in dentition, and the fossil record of body and brain size changes over time. The links between parental effort and allocation of care to infant growth and survival generate speculative scenarios of sex-specific parental care allocation; I then explore hominin social evolution?—mating system and childhood—?for the lineages thought to lead to modern Homo, and for those that coexisted with ancestors of Homo.     

Developmental study of tripeptidyl peptidase I activity in the mouse central nervous system and peripheral organs

Tripeptidyl peptidase I (TPPI) — a lysosomal serine protease — is encoded by the CLN2 gene, mutations that cause late-infantile neuronal ceroid lipofuscinosis (LINCL) connected with profound neuronal loss, severe clinical symptoms and early death at puberty. Developmental studies of TPPI activity levels and distribution have been done in the human and rat central nervous systems (CNS) and visceral organs. Similar studies have not been performed in mouse. In this paper, we follow up on the developmental changes in the enzyme activity and localization pattern in the CNS and visceral organs of mouse over the main periods of life — embryonic, neonate, suckling, infantile, juvenile, adult and aged — using biochemical assays and enzyme histochemistry. In the studied peripheral organs (liver, kidney, spleen, pancreas and lung) TPPI is present at birth but further its pattern is not consistent in different organs over different life periods. TPPI activity starts to be expressed in the brain at the 10th embryonic day but in most neuronal types it appears at the early infantile period, increases during infancy, reaches high activity levels in the juvenile period and is highest in adult and aged animals. Thus, in mice TPPI activity becomes crucial for the neuronal functions later in development (juvenile period) than in humans and does not decrease with aging. These results are essential as a basis for comparison between normal and pathological TPPI patterns in mice. They can be valuable in view of the use of animal models for studying LINCL and other neurodegenerative disorders.     

Middle Childhood and Modern Human Origins

The evolution of modern human life history has involved substantial changes in the overall length of the subadult period, the introduction of a novel early childhood stage, and many changes in the initiation, termination, and character of the other stages. The fossil record is explored for evidence of this evolutionary process, with a special emphasis on middle childhood, which many argue is equivalent to the juvenile stage of African apes. Although the “juvenile” and “middle childhood” stages appear to be the same from a broad comparative perspective, in that they begin with the eruption of the first molar and the achievement of the majority of adult brain size and end with sexual maturity, the detailed differences in the expression of these two stages, and how they relate to the preceding and following stages, suggest that a distinction should be maintained between them to avoid blurring subtle, but important, differences.     

Ontogenesis of the cricket Gryllus argentinus Sauss. (Orthoptera, Gryllidae)

The development of Gryllus argentinus Sauss. was studied under stable laboratory conditions: the temperature of 26°C, the air humidity of 60%, and the photoperiod of 12h light: 12 h dark. The life cycle of Gryllus argentinus includes four stages: egg, pronymph, nymph, and adult. The duration of embryonic development is 18 days. The depth of egg bedding in the peat is 9.63 ± 0.12 mm (n =145), the clutch containing 2–4 eggs. A female can lay over 1100 viable eggs during the entire oviposition period. Nymphal development includes 9 instars and lasts 97 days. The duration of nymphal instars (days) is: I—5; II—6; III—6; IV—6; V—8; VI—10; VII—13; VIII—14; IX—29. The duration of the adult life is 51 days in males and 69 days, in females. In the imaginal ontogenesis of males and females, three periods can be distinguished: pre-reproductive, reproductive, and postreproductive. Males start to emit the aggressive signal on the 6th (5–8th) day (the pre-reproductive period). They enter the reproductive period (start to emit the calling song) on the 9th (8–13th) day. Females enter the reproductive period (become capable of responding to the calling song and of copulation) on the 9th (8–10th) day. Oviposition starts on the day after the first copulation. The reproductive period lasts about 40 (15–59) days in males and 58 (21–70) days in females. The post-reproductive period starts in females at the moment of finishing the egg laying period and in males, with disappearance of reproductive behavior. The period ends in the animal’s death.     

Life history of yellow baboons: Physical development,reproductive parameters,and infant mortality

Longitudinal data from a population of yellow baboons,Papio cynocephalus, in the Amboseli National Park, Kenya, provide life history parameter estimates. Females reached menarche at approximately four-and-a-half years of age and then cycled for approximately a year before first conception. Postpartum anestrum averaged 12 months but ranged from six to 16 months. In cases of still births or infant death during postpartum amenorrhea, females commenced cycling after approximately one month. In mature females the time spent cycling before conception was five months on the average with a range from one to over 18 months. Only half of all full-term pregnancies resulted in infants who survived the first year of life; only a third, in infants who survived until the birth of their mother’s next infant. In comparison with data from laboratory colonies, our data indicate that female baboons in Amboseli are older at birth of first infant. They have, on the average, a somewhat shorter interbirth interval than was estimated from earlier crossectional field data, and therefore spend a larger portion of their adult life pregnant, but have a much longer interval—at least three years on the average—between the birth of an infant and the birth of that infant’s next older surviving sibling. A number of morphological changes in immature baboons are described.     

Dental Eruption Series and Replacement Pattern in Miocene <Emphasis Type="Italic">Prosantorhinus</Emphasis> (Rhinocerotidae) as Revealed by Macroscopy and X-ray: Implications for Ontogeny and Mortality Profile

Fossil evidence of complete sequences of dental ontogeny in extinct mammals is rare but contains valuable information on the animal’s physiology, life history, and individual age. Here, we analyzed an exceptionally high number of juvenile dentaries at different developmental stages including highly fragile tooth germs of the extinct rhinoceros Prosantorhinus germanicus from the Miocene fossil lagerstätte Sandelzhausen in Germany. We used dental wear stages, eruption stages, and tooth germ development in order to reconstruct the tooth replacement pattern for P. germanicus. The results allow for the distinction of 11 dental eruption stages and document a tooth eruption sequence of (d2, d3), (d1, d4), m1, m2, p2, p3, p4, m3; a pattern identical to that reported for the extant African rhinoceros, Diceros bicornis. Moreover, our findings indicate that P. germanicus falls into the life history category of slow-growing, long-living mammals. The dental eruption stages of the fossil rhinoceros were correlated with data of living rhinoceroses in order to gain insight into the age-at-death distribution of P. germanicus at Sandelzhausen. The juvenile mortality profile of P. germanicus shows a trend of selective mortality at an inferred age range of about 3 months to 3 years. As this age range represents a life phase of increased natural risk of mortality, our findings indicate a gradual accumulation of corpses (attritional fossil assemblage). This result supports the interpretation of a taphocenosis found at the Sandelzhausen fossil site.     

Dental identification and age determination in Elephas maximus

The dentition of an elephant (fossil or extant) can yield clues to the animal's age species identity, provided the teeth are correctly identified. Identifying the serial category of elephant teeth is difficult because the size, shape and position of each tooth changes throughout life, as the teeth form, erupt, wear and move throught the jaw. In the present study, teeth from over 100 museum specimens of the Asian elephant ( Elephas maximus ) were the basis for establishing size ranges for cheek teeth in six serial categories (designated by Roman numerals I to VI). Although the teeth vary greatly and overlap in their dimensions, reliable identifications (as well as estimates of an individual's age in years) can be obtained using three or more measurements. An appreciation for dental variability in Elephas maximus will demand a re-evaluastion of frequently-cited examples of macroevolutionary patterns within the Elephantidae.     

Life history of hamadryas baboons: Physical development,infant mortality,reproductive parameters and family relationships

Demographic and life history parameters were estimated for a band of free-ranging hamadryas baboons, observed for 5.5 years in Ethiopia. Age-related changes in body weight and dentition were found to be delayed relative to laboratory-reared baboons. On the average, females reached menarche at 4.3 years of age and had their first infant at the age of 6.1 years. The mean interbirth interval was 24 months if the infant survived this period. The survival of infants and juveniles was higher compared to Amboseli yellow baboons, but somewhat lower than in gelada baboons in the Simen Mountains. Males acquired their first juvenile or adult female at the age of 8.5 to 11 years. Male-female pair-bonds lasted several years in most cases. The Cone Rock baboons were organized in a four-level social structure. The troop could split into bands, bands were divided into clans, and clans into one-male units with bachelor followers. The exchange of individuals between social units predominantly occurred within the band. All males of known origin became adult members of their presumed natal clan. Most females transferred also within clans, and juvenile females tended to remain in their natal clan. Females lost by one male to several rivals tended to reassemble in the same new one-male units later on.     

Plant competitive ability and the transitivity of competitive hierarchies change with plant age

Plant competitive effect and response ability are known to change with plant age, however it remains unclear how competitive hierarchies among plant species change as plants age and transition between life stages. We examined the competitive interactions among seven species in all pairwise combinations in a greenhouse experiment. Competitive effect and response were measured as the relative yield (RY) for each target-neighbor species combination for both seedling and adult plants. Competitive hierarchies were constructed based on competitive effect and response scores, and we examined the degree of transitivity in the seedling and adult competitive hierarchies. The competitive effect hierarchy did not vary substantially with plant age, while the competitive response hierarchy was highly variable between juvenile and adult plants. Competitive effect and response ability were positively correlated at both plant stages. The seedling relative yield matrix was predominantly transitive, while there were far fewer transitive competitive relationships among the adult plants. The breakdown of the clear competitive hierarchy among seedlings as plants aged may explain why competition does not appear to be an active mechanism structuring some late-successional plant communities. In early-successional communities, interactions among seedlings with a clear competitive hierarchy may establish competitive ability—abundance relationships that persist as a legacy effect even though the breakdown of the competitive hierarchy among adult plants removes competition as an active mechanism structuring some late-successional plant communities.     

The growth pattern of chimpanzees: Somatic growth and reproductive maturation inPan troglodytes

Growth of chimpanzees reared at the Kumamoto Primates Park of Sanwa Kagaku Kenkyusho Co. Ltd. was studied cross-sectionally from the viewpoints of somatic growth and reproductive maturation. Distance and velocity curves were expressed using spline function method. Males showed adolescent growth acceleration in body weight, with a peak at 7.86 yrs of age, but not in trunk length. Females showed continuous rapid growth from mid-juvenile to adolescent phase in both body weight and trunk length, but no isolated adolescent spurt. The Sanwa chimpanzees matured at about 12.5 yrs of age for females and 15.0 yrs for males. The mean adult weights and trunk lengths were 53.2 kg and 507.8 mm for males and 42.7 kg and 481.6 mm for females. The Sanwa chimpanzees had similar growth patterns to those of the Yerkes chimpanzees, although they showed a slight delay in infancy, and a higher growth rate from the early juvenile phase onwards. Growth patterns in these two laboratories may be regarded as “normative” for laboratory-reared chimpanzees. They matured earlier than wild chimpanzees by more than two years. The major reason for the retarded maturation in wild chimpanzees is the delay of growth from infant to the early juvenile phases (0–4 yrs of age), probably owing to a limited nutritional supply from the mother. Development of the testes comprised three phases: slow growth from infant to juvenile (until 6.4 yrs); rapid growth around adolescence (until 9.2 yrs); and adult (mean testicular volume, 187 cm³). Setting the nutritional standard at 2,000–2,600 Cal/day (= Kcal/day) per adult, calories were considered for captive chimpanzees in each age class.     

Ultimate mechanisms of age-biased flea parasitism

Mechanisms that cause nonrandom patterns of parasite distribution among host individuals may influence the population and evolutionary dynamics of both parasites and hosts, but are still poorly understood. We studied whether survival, reproduction, and behavioral responses of fleas (Xenopsylla conformis) changed with the age of their rodent hosts (Meriones crassus), experimentally disentangling two possible mechanisms: (a) differential survival and/or fitness reward of parasites due to host age, and (b) active parasite choice of a host of a particular age. To explore the first mechanism, we raised fleas on rodents of two age groups and assessed flea survival as well as the quantity and quality of their offspring. To explore the second mechanism, three groups of fleas that differed in their previous feeding experience (no experience, experience on juvenile or experience on adult rodents) were given an opportunity to choose between juvenile and adult rodents in a Y-maze. Fleas raised on juvenile rodents had higher survival and had more offspring that emerged earlier than fleas raised on adults. However, fleas did not show any innate preference for juvenile rodents, nor were they able to learn to choose them. In contrast to our predictions, based on a single previous exposure, fleas learned to choose adult rodents. The results suggest that two mechanisms—differential survival and fitness reward of fleas, and associative learning by them—affect patterns of flea distribution between juvenile and adult rodents. The former increases whereas the latter reduces flea densities on juvenile rodents. The ability of fleas to learn to choose adult but not juvenile hosts may be due to: (a) a stronger stimulus from adults, (b) a higher profitability of adults in terms of predictability and abundance, or (c) the evolutionary importance of recognizing adult but not juvenile hosts as representatives of the species.     

Cumulative energy demand for selected renewable energy technologies

Calculation of Cumulative Energy Demand (CED) of various energy systems and the computation of their Energy Yield Ratio (EYR) suggests that one single renewable energy technology cannot be said to be the best. Due to the difference in availability of renewable energy sources, their suitability varies from place to place. Wind energy converters, solar water heating systems and photovoltaic systems have been analysed for different types of locations. Comparing the general bandwidth of performance of these technologies, however, the wind energy converters tend to be better, followed by solar water heating systems and photovoltaic systems. Since a major part of the methodology of findingCED is very close to that of life cycle assessment and also because of the dominance of environmental impacts caused by the energy demand in the entire life cycle of any product or system, it is suggested that theCED can be used as an indicator of environmental impacts, especially in the case of power producing systems. Keywords: Cumulative energy demand; life cycle assessment; energy yield ratio; photovoltaics; solar water heating; wind energy Abbreviations: CED — Cumulative Energy Demand; EYR — Energy Yield Ratio; LCA — Life Cycle Assessment; Photovoltaics — PV; WEC — Wind Energy Converters     

河南栾川发现直立人化石及其演化意义

洛阳考古研究院2012年5月至10月在栾川孙家洞作抢救性发掘,于原生层位发现古人类化石,同时伴有大量哺乳动物化石,以及少量人工石制品。根据伴生动物群的初步鉴定,栾川古人类的生存时代为中更新世。6件古人类化石代表3个个体:1个成年人和2个未成年人,未成年人的牙齿生长发育阶段分别与6～7岁和11～12岁的现代青少年相当。栾川孙家洞古人类牙齿具有一定的原始性,明显区别于现代人,其形态大小位于周口店直立人牙齿的变异范围内,可归入直立人的形态范畴;同时具有东亚古人类及现代蒙古人群的地区性特征。基于幼年个体上下颌骨的牙齿发育,推测栾川古人类第一臼齿萌出年龄可能接近6岁,提示具有接近于现代人的牙齿生长模式和生活史特点。栾川中更新世古人类化石的发现为中国古人类连续演化假说提供了新证据。     

Growth and Development in Wild Owl Monkeys (<Emphasis Type="Italic">Aotus azarai</Emphasis>) of Argentina

Life history predicts that in sexually dimorphic species in which males are the larger sex, males should reach sexual maturity later than females (or vice versa if females are the larger sex). The corresponding prediction that in sexually monomorphic species maturational rates will differ little between the sexes has rarely been tested. We report here sex differences in growth and development to adulthood for 70 female and 69 male wild owl monkeys (Aotus azarai). In addition, using evidence from natal dispersal and first reproduction (mean: 74 mo) for 7 individuals of known age, we assigned ages to categories: infant, 0–6 mo; juvenile, 6.1–24 mo; subadult, 24.1–48 mo; adult >48 mo. We compared von Bertalanffy growth curves and growth rates derived from linear piecewise regressions for juvenile and subadult females and males. Growth rates did not differ between the sexes, although juvenile females were slightly longer than males. Females reached maximum maxillary canine height at ca. 2 yr, about a year earlier than males, and females’ maxillary canines were shorter than males’. Thus apart from canine eruption and possibly crown–rump length, the development of Azara’s owl monkeys conforms to the prediction by life history that in monomorphic species the sexes should develop at similar paces.     

Toothcomb homology and toothcomb function in extant strepsirhines

Contrary to some recent assertions, there are no persuasive ways for determining the homologies of indriid toothcomb teeth and the resulting dental formulas. Most of the presumably distinctive features of procumbent “canines” are also seen in incisors, and vice versa. Thus, there are at least three plausible dental formulas for indriid deciduous teeth and two for the permanent dentition. All formulas are compatible with the distribution of teeth in fossil strepsirhines. Similar arguments apply to strepsirhine toothcombs as a whole, but the absence of three-incisored ancestors in the fossil record strongly supports the conclusion that the dental formula of nonindriids is 2.1.3.3. for the lower dentition. There are also alternative interpretations of the original function of the toothcomb. Recent arguments which purport to demonstrate that the toothcomb evolved originally as a sap-feeding adaptation fail that purpose. The ontogeny of infant lemur behavior suggests that the original function involved grooming rather than feeding if the data are interpreted in a Haeckelian context.     

Diagenesis of growth bands in fossil scleractinian corals: identification and modes of preservation

Light and dark bands in fully recrystallized fossil hermatypic corals are generally interpreted to represent annual growth increments reflecting a photosymbiotic life style—an interpretation of far reaching significance in palaeoecology. In this paper we describe annual growth bands in the colonial coral Porites in a perfect (aragonite and microstructures retained) and fully recrystallized (sparry calcite mosaic) style of preservation from sediments of Late Miocene age (Crete, Greece). Analysis of a continuous spectrum of transitional preservational stages shows that in Miocene Porites preservation of the growth banding was controlled by preferential dissolution of the high-density band associated with cementation by drusy calcite spar during freshwater diagenesis/shallow burial diagenesis. Marine precipitates (pelletoidal Mg-calcite) preferentially accumulated along tabulate dissepiments producing an additional growth rhythmicity. Massive Porites had annual growth rates of ∼4.0 mm, whereas in ramose branching Porites, a conspicuous banding is formed by concentrations of marine micropelletoidal cement along dissepiments at ∼1.8 mm spacing. If taken as annual growth increments, these bands represent very low extension rates, however, they may rather reflect subannual forcing functions (i.e., lunar cycles). An identical scenario of precipitation and concentration of pelletoidal carbonate along dissepiments and dissolution-controlled documentation of growth bands can be inferred for Late Jurassic microsolenids. Therefore, growth bandings in fossil corals potentially reflect both, monthly and annual cycles. Consequently, care must be taken when using coral growth bands in palaeoecology and palaeoclimatology.     

Molecular cloning,structure, and testis-specific expression of MFSJ1, a member of the DNAJ protein family,in the Japanese monkey (Macaca fuscata)

A strong signal of cDNA product was identified in adult and senile testes of the Japanese monkeys (Macaca fuscata) using differential display PCR analysis. Its full-length cDNA was molecular-cloned by RT-PCR using adult testis mRNA as templates. The predicted open reading frame encoded a protein of 242 amino-acid residues. It contained J domain in the NH(2) terminal region and Gly/Phe-rich domain in the middle of protein, which are typical structural domains of the DnaJ protein family. We named this gene, MFSJ1, for spermatogenic cell-specific DNAJ homolog in the Japanese monkey. Northern blot analysis of RNAs from various somatic and germinal tissues revealed that the MFSJ1 gene is specifically expressed in testis and is active at adult and senile stages but is scarcely expressed at the juvenile stage. In situ hybridization revealed that the MFSJ1 gene is expressed mainly in spermatids and the expressional potential is maintained from adult to senile stages. MFSJ1 was found to have high similarity (71% identity) with MSJ1, mouse spermatogenic cell-specific DnaJ homolog. Although this type of DnaJ-like protein has not been found in other mammals, it may be essential for mammalian spermatogenesis.     

The life history of Trichoniscus pusillus pusillus (Crustacea: Isopoda)

The methods are given which were used to determine the number of stages in the life history of Trichoniscus pusillus pusillus Brandt, 1833 and the stages are described as far as possible. Not all stadia can be separated on morphological grounds and animals extracted from monthly litter samples were measured and the stadia separated by use of probability paper. This method proved quite successful and confirmed the characterization of the three earlier juvenile stadia on morpholigical grounds and the number of the later juvenile stadia determined from laboratory cultures. There are six juvenile and five adult stadia.