The present ecological situation of mankind - analysis and consequences.

As the number of human individuals increases on a planet of invariable size and measures, the ecological conditions vary to a corresponding extent. Quite a number of biotic and abiotic factors are a matter of daily news as well as of current scientific discussions. In this contribution, eleven ecological fields concerning human life are analysed: • area available with respect to various competing utilisations, • fresh water needed as drinking water, for industrial processes and for irrigation as well as for other human purposes, • food production, nutrition and related aspects, • required fossil and regenerative energies, • atmosphere and climate, • marine ecology and fisheries, • human waste and ecological aftereffects, • the ecological functions of forests for human life, • biodiversity, • the Ecological Footprint, and • the development of human population increase. As the very characteristic of the ecological network, almost all these factors interact in obvious or clandestine ways. In the given frame of this article, the manifold interchanging influences are discussed, and consequences for a sustainable human life are drawn.

The evolution of the upright posture and gait--a review and a new synthesis.

During the last century, approximately 30 hypotheses have been constructed to explain the evolution of the human upright posture and locomotion. The most important and recent ones are discussed here. Meanwhile, it has been established that all main hypotheses published until the last decade of the past century are outdated, at least with respect to some of their main ideas: Firstly, they were focused on only one cause for the evolution of bipedality, whereas the evolutionary process was much more complex. Secondly, they were all placed into a savannah scenario. During the 1990s, the fossil record allowed the reconstruction of emerging bipedalism more precisely in a forested habitat (e.g., as reported by Clarke and Tobias (Science 269:521-524, 1995) and WoldeGabriel et al. (Nature 412:175-178, 2001)). Moreover, the fossil remains revealed increasing evidence that this part of human evolution took place in a more humid environment than previously assumed. The Amphibian Generalist Theory, presented first in the year 2000, suggests that bipedalism began in a wooded habitat. The forests were not far from a shore, where our early ancestor, along with its arboreal habits, walked and waded in shallow water finding rich food with little investment. In contrast to all other theories, wading behaviour not only triggers an upright posture, but also forces the individual to maintain this position and to walk bipedally. So far, this is the only scenario suitable to overcome the considerable anatomical and functional threshold from quadrupedalism to bipedalism. This is consistent with paleoanthropological findings and with functional anatomy as well as with energetic calculations, and not least, with evolutionary psychology. The new synthesis presented here is able to harmonise many of the hitherto competing theories.

Hierarchical organization of a reference system in newborn spontaneous movements.

In this paper, we studied spontaneous newborn movements regarding the coordination of the four limbs, arms and legs, from a dynamic perspective. We used the method of recurrence plots to analyse the kinematic data from audiovisual recordings of neonates. We identified temporal and spatial synchronization of the four limbs that resulted in high recurrence patterns of biomechanical reference configurations. Furthermore, we identified transitions between linear and nonlinear epochs in the movement behavior of newborns on different time scales by means of recurrence quantification analysis. Results are discussed in the context of the concept of a structural hierarchy, in which different time scales correspond to hierarchical levels of organization.

Human ears grow throughout the entire lifetime according to complicated and sexually dimorphic patterns--conclusions from a cross-sectional analysis.

In most of its anatomical constituents, e.g. in the Helix, etc., the external human ear is homologous to that of all Primates and Scandentia (tree shrews). Thus, its genetic basis is largely older than 60 Mio yrs. Based upon the observation of lifelong growth of the ear (e.g. Montacer-Kuhssary 1959), we aimed to elucidate the growth of the human ear in a more detailed way throughout life and in both sexes. On standardized photographical material collected randomly in Berlin (Germany), we measured N = 1448 ears from neonate children to volunteers of 92 yrs in age. 10 longitudinal measurements and 5 further anatomical parameters yielded a data set of roughly 19,000 data in total. Based upon our cross-section analysis, we quantified several sexual dimorphisms. Furthermore, we deduced ontogenetic developments and, partially, corrected their proportions for secular acceleration and body height shrinking with age. At the time of birth, in proportion to the body, the external ear was even bigger than the large head and continued growing rather linearly throughout life, reaching the highest average lengths in the volunteers aged over 85 yrs. The large yearly increases during childhood began to diminish at as early an age as 8 or 10 yrs. In all parameters where post adult growth was observed, female ears showed a lesser increase than those of men. The greatest ear length in females was 52 mm (SD +/- 4.3 mm) at birth, 61 mm (SD +/- 3.9 mm) at around 20 yrs of age and 72 mm (SD +/- 4.6 mm) in women older than 70 yrs. For the male subjects, these three values were: 52 mm (SD +/- 4.1 mm), 65 mm (SD +/- 4.0 mm) and 78 mm (SD +/- 4.8 mm), respectively. In spite of extreme premature growth of the auricle and its further lifelong growth, three anatomical features of the ear did practically not grow at all after birth: the width of the Concha auriculae and of the Incisura intertragica, as well as the diameter of the helical brim of the auricle. The problems arising concerning the functions and selective values of all these very unusual proportions and growths are discussed. The ontogenetic development of one or more pretragal skin folds could be used as a contribution to age estimations in forensic anthropology.

Recurrence plot analyses suggest a novel reference system involved in newborn spontaneous movements.

The movements of newborns have been thoroughly studied in terms of reflexes, muscle synergies, leg coordination, and target-directed arm/hand movements. Since these approaches have concentrated mainly on separate accomplishments, there has remained a clear need for more integrated investigations. Here, we report an inquiry in which we explicitly concentrated on taking such a perspective and, additionally, were guided by the methodological concept of home base behavior, which Ilan Golani developed for studies of exploratory behavior in animals. Methods from nonlinear dynamics, such as symbolic dynamics and recurrence plot analyses of kinematic data received from audiovisual newborn recordings, yielded new insights into the spatial and temporal organization of limb movements. In the framework of home base behavior, our approach uncovered a novel reference system of spontaneous newborn movements.

Female sexual behavior, but not sex skin swelling, reliably indicates the timing of the fertile phase in wild long-tailed macaques (Macaca fascicularis).

The extent to which catharrine primate males are able to discern the fertile phase during the female ovarian cycle under natural conditions is still debated. In a recent study, we showed that wild male long-tailed macaques are able to detect the fertile phase, but the cues males used to assess female reproductive status remained unclear. In the present study, we tested female sex skin swelling and specific female behaviors for their reliability in signaling the fertile phase, as determined by measurement of fecal estrogens (E) and progestogens (P) during nine ovulatory cycles in seven free-ranging females. We found that changes in sex skin swellings showed a significant positive correlation to the E/P ratio, but swelling size did not significantly differ between cycle phases. In contrast, the frequency of two of the tested female behaviors, namely initiation of sexual interactions and reaching back for the male during copulation, was not only correlated with female reproductive hormones, but was significantly elevated during the fertile phase compared to nonfertile phases of the cycle. We thus conclude that female sex skin swelling does not reliably indicate the timing of the fertile phase in long-tailed macaques, whereas certain female behaviors do. Since cycles differed considerably in the number of males with which females had sexual interactions as well as in the number of sexual interactions with dominant males, the signaling character of these specific female behaviors appears to be robust against inconsistencies in these social variables. Female behavior might therefore play an important role in the recognition of the fertile phase by male macaques under natural conditions.

Results of an explorative empirical study on human mating in Germany: handsome men, not high-status men, succeed in courtship.

Recent research on human mating depicts men as searching for physical attractiveness (PA) and women as searching for status. To identify the mechanisms which lead to universal, biologically interpretable structures in social processes, we focused on the proximate causes for inter- and intrasexual differences in human mating preferences, attraction, and tactics. We collected data on 180 young singles (mean age 26.9 years) without a steady relationship. A questionnaire and a video sequence (20-30 seconds) of each subject was taken. Next, each video sequence was rated by approximately 20 individuals of the opposite sex, who also participated in this study. Surprisingly, the answers given by male and female subjects regarding sociosexual behaviour and mating preferences are predominantly congruent. Sex differences among preferences for good looking and high-status partners were small or even insignificant. Lower educated subjects had considerably higher status preferences than higher educated individuals. In both sexes, PA was much more preferred in a potential partner than status. For both sexes, physical appearance was decisive for the subject's dating attractiveness. Male, but not female dating attractiveness also correlates with a kind and charismatic appearance. Furthermore, there was a positive linear relationship between men's PA and their number of sexual partners within the last year. Men with more than four sexual partners were all above-average in PA, while the most attractive women had a medium number of sexual partners. However, in this respect, status had no influence. The results show that sex differences in mating are more complex than hitherto assumed.

Age structure and selected pathological aspects of a series of skeletons of late medieval Bernau (Brandenburg, Germany).

The age distribution of an excavation site from the late Middle Ages (beginning of the 13th century until 1598) in Bernau (Brandenburg, Germany) that contained 252 skeletons shows a mortality maximum at the age classes infants I and mature. The lowest mortality was calculated for the adult age class. 51.6% of the individuals died before the age of 20 years. The mortality rate of young women was higher than that of young men. The life expectancy of the total population was 25 years. Altogether, 87 adult skeletons were examined for degenerative joint diseases. Many of the examined joints showed indications of beginning osteoarthritis; the intensity of the disease was low or medium severe. The highest values were found for the hip joint, followed by the elbow and the knee. For all joints examined, women were less often and to a lesser extent affected than men, which was noticeable best in the upper extremity. Harris lines were found in 75% of the children, 4.7 per average individual. No such lines were found by the age of one year, the peak value of the frequency being recorded at the age between 2 and 3 years. This can be correlated to the weaning period. The comparison to a rural population yielded a higher load with Harris lines in the small village, which, however, was not correlated to a higher mortality. Altogether, the population of Bernau is characterised by good living conditions and a considerable chance of survival for the children, as well as by a labour system, dominated by crafts and farming.

"Right-trunkers" and "left-trunkers": side preferences of trunk movements in wild Asian elephants (Elephas maximus).

In this article, the side preferences of feeding-related trunk movements of free-ranging Asian elephants (Elephas maximus) were investigated for the first time. It is hypothesized that a functional asymmetry of the trunk is necessary to perform skillful feeding movements more efficiently. This might be connected with a corresponding hemispheric specialization. Video recordings of 41 wild elephants provided frequencies and durations of the following trunk-movement categories: object contact, retrieval, and reaching. In each category, individual side preferences were found. The strength of side preferences varied between the trunk-movement categories and the sexes. Mean durations of retrieval and reaching correlated negatively with the strength of side biases. Comparing the side preferences in the unpaired trunk with analogous phenomena in other unpaired grasping organs and in primate handedness. the authors discuss possible explanations for the evolution of asymmetries in unpaired grasping organs.

Kinematics and ontogeny of locomotion in monkeys and human babies.

Early ontogenetic stages are often assumed to reflect or to be similar to past phylogenetic stages within the evolution of man. Therefore, as a first step, the quadrupedal crawling locomotion of human children was analysed and compared to the quadrupedal walk of Macaca fascicularis. The movements of the human child were not only more irregular, they differed from the walk of the monkey mainly through extraordinarily short swing phases, and also through strong scoliotic movements of the spine. There is a compulsory synchronisation in the hip and knee joint movements of the human crawling baby. We conclude that human crawling may be a behavioural recapitulation of a quadrupedal evolutionary stage. However, with reference to kinematics, man is not only characterised by his unique, habitually bipedal, upright gait but also by a second, equally unique locomotion, namely crawling, which he assumes for a short phase during his first year of life.--The walking movements of the limbs in toddling infants were mainly characterised by i) rather stiff, abducted arms, which were moved mostly by spine torsions (similar to those of bipedally walking Gorilla) and not as a suspensory pendulum. However, they rather work as levers for the elastic torsion pendulum of the spine. ii) They are also characterised by frequently lacking the minor knee flexion, which occurs at about the heel strike within each stride of the adult human. Besides many other details of the results, foot movements differed from adult ones mainly in that the whole plantar surface was placed flat on the ground within a few milliseconds.

A theory on the evolution of the habitual orthograde human bipedalism--the "Amphibische Generalistentheorie".

The theory is formulated that ubiquitous scarcity of energy is one of the main motors of evolution. It is concluded that our primate ancestors never came down from the trees, but rather they have always been (semi-)terrestrial. This habit is probably an old symplesiomorph trait, older than primates themselves. Terrestrial habits in primates correlate to body weight in small systematic groups (e.g., large genera, families) but are, overall, completely independent from individual body mass. An omnivorous, semiterrestrial quadrupedal locomotor generalist seems to be the most probable morpho- and eco-type for our ancestor at the threshold of a hominoid stage of our evolution. The theory presented here suggests that our hominoid ancestor lived in gallery forests and changed strata in order also to inhabit the savannah habitat as well as the shallow water of the rivers or coasts. Foraging in a wading manner was extremely favourable for an effective and, especially, seasonally independent, animal protein supply. Anatomical adaptations to orthogradism and proportions of the extremities are discussed in relation to the necessary and frequent change of habitat strata. Ultimately, human bipedalism is seen here to be derived as a consequence of the centre of body mass, which is, in primates, near the hind extremities. By contrast to other mammals entering the water, wading primates sink back on their hind limbs. Selective forces for habitat use, limb proportions and wading habits are discussed, as well as the phylogenetic origin of human affinity to water and shores in all peoples through all times, from australopithecine times through the Paleolithic until today.