Tag: biologie

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Fertility Fecundity

The scientific debate around changes in fertility has focused on social, economic and cultural factors to explain the drop in total fertility rates in OECD countries. The baby boom years of the 1950s and early 1960s had come to an end following the spread of new forms of birth control like contraception from the late 1960s onwards. The trend is very obvious and yet, the explanations of the trend might lack a more profound analysis of fecundity in addition to the socio-economic explanations. Shakkebaek et al. (2025) point for example to the little known effects of environmental (pollution) factors on the biological reproduction capability of humans (men and women).
Additionally, psycho-social factors like “the German Angst” fear about future developments in many social and economic fields might have direct effects, but also indirect effects on human biology. We know still very little about such feedback loops or feedback effects. We are more convinced, than we actually have hard evidence, that the BSP, SPB or PSB (B=Bio, S=Social, P=Psycho) spheres are interwoven, but an ambitious research agenda is called for to enlighten the issue. The big invisible elephant in the room might be environmental issues that enter into the fertility equations more than we have expected for many years. A nice working hypothesis for an ambitious and overdue research agenda.

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Spring Newborn

For many species spring is the time for newborns to enter into life. Pigeons in the neighborhood have completed the breeding phase and they called upon the newborn to crack the shell open. Nourishment is already abundant in the surroundings and parents appear to be impatient to quit the guarding of their offsprings. Time for the next generation to take over a similar role soon.
Pigeons don’t ask questions about fertility. They reproduce in abundance if the environmental conditions are alright.
Human beings are a danger for them as some feed them well, but others defend their territory, housing or living space against any intrusion by pigeons. Compromises are not easy to accomplish.
Fans of the song writer Georg Kreissler keep humming with dark humor: „Geh‘n wir Tauben vergiften im Park …“. The struggle for survival of species has changed in kind and we are, more than ever, responsible for the living conditions of other species as well.

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Warming consequences

The live of honey bees is rather busy and well organized. Global warming necessitates new risks and new opportunities for honey bees. The flowering season starts earlier in Europe and bees start earlier ro their collection of nectar and their service of pollination to other flowers. In early April 2025 in France near Paris we observe wild bees already in their daily routine. However, the risk of cold nights is still there, albeit those building their homes below the surface are a bit less at risk during a frosty night. Seeking a clever shelter is a good strategy for survival particularly at times of global warming. Some kinds of wild bees seem to sense this already changing homes from one season to next one. Humans remain their toughest enemies as they restrict their choices quite severely. Man-made pollution and herbicides are beyond bees’ control and cause havoc in the ecosystem of bees. Apiculture is an interesting science also for social scientists as this forerunner species of the matriarchy has evolved into a well-organized productive society. They are a bit harsh to each other and communication is rather unidirectional, but an interesting social cosmos of its own kind.

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Not learning

For decades our attention has been focused on how learning works. However, at the beginning of 2025 it might be more important to shift our focus of learning research on “not learning”. Recent research on learning includes the study of “social learning” of mice (Winiarski et al. 2025) and the related brain mechanisms that are involved in social learning like the prelimbic cortex.
For our human societies we also rely to a great deal on social learning. In mice, however, the disruption of the prelimbic cortex causes mice to no longer seek “social information related to rewards” from other mice. In Eco-HAB cages these mice follow their scent capabilities to “sort” their information seeking from for example higher “social status animals”. This tested reward seeking behavior allows clues to how learning works. The intervention to disrupt the synaptic plasticity in a later phase of the experiment reveals less social learning from the network social information and fewer contributions to the social network.
Only intact neural plasticity in the prelimbic cortex ensures the maintaining of the social structure. Of course it is highly questionable, whether these results based on animal experiments tell us anything about social structure and social learning in other mammals, but there might be reasons to search for explanations of “no social learning” in humans as well.

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Animal Longevity

  1. From time to time it is interesting to study animals from many species to maybe learn from them about longevity. Roberto Salguero-Gómez (LINK) developed a sociality continuum and compared 152 species across 13 taxonomic classes. The study reiterates and generalizes the many studies of single species and finds that „more social species live longer, have more generation time and longer reproductive windows“.  Social structures amongst animals of the same species influence survival and reproduction as basic demographic processes. These processes determine to a large extent the size of animal populations. Sociality appears to be a major contributor to longevity compared across species. These processes determine the survival of rather solitary species like panda bears (running higher risks of extinction) compared to populations of bees with rather hierarchical predefined social structures. The spotted hyenas developed cooperative hunting and communal care which allows for effective survival compared to other species. Sociality is specific to species and therefore largely determined by genetic factors. Nature rather than nurture is at work. However, species where reproduction occurs later allow for learning curves of sociality. In other words even within species there is scope to improve longevity through sociality. Migration patterns or experience with migration might be yet another determinant of survival or longevity as climate change poses new challenges to many species.
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Chinny Trait

In evolutionary biology there is still a discussion about the functional explanation of why humanoids developed a chin. A recent paper by Meyer-Rochow adds a new functional explanation for the evolution of the chin to the literature. Across cultures and sufficiently distant populations of humans, similar patterns of the use of the chin have been observed. In comparison to other species under the superfamily “Hominoidea”, our bites are only of minor strength and apes, Orang Utans have not developed a chin quite like us, homo sapiens. Origins of the chin as “weapon” in fighting and broader social selectivity remain hypotheses without sufficient proof of evidence.
In addition to the functional explanations of easier “mastication” or formation of words, chins might serve as an additional part of the body to hold items to the chest. This function, of holding tools or stuff could have been an advantage for our ancestors and became a favoured trait. During the pandemic our chins became a supporting or hindering reason in the struggle to wear masks for extended periods of time (see image below).
Nowadays, we ask ourselves about the social selectivity into becoming a violin player with this important function of the jaw and chin to hold the instrument. A rival hypothesis is, of course, that holding things with our mouth, like needles or screws, in sewing or handicrafts could eventually make the chin disappear. The bipedalism of hominids, freed our hands for other tasks and the evolution of a chin could similarly reinforce the efficient use of our hands.
Novel use cases for the chin, like holding your smartphone while typing on a keyboard or while opening doors, might enhance the chinny trait of hominids.
Over hundred of thousands of years the interaction of the bio->psycho->social (BPS) spheres of life may have interesting traits for us down (or up) the evolutionary line.
(Image: European parliament, Brussels 2020-7-23 address by Ursula von der Leyen in “masked assembly”).

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Birds again

There are many ways to have more birds again in inner cities. Less pollution and poison are part of the solution. Second, increase the food available to birds. Some plants or vegetation is more suited than the other one. Combined with the question of cooling houses in summer and more isolation in autumn and winter, the greening of facades in cities has a simple effect to provide hiding, nesting and feeding spaces for birds. Birds will discover this vegetation as their natural habitat offering relatively safe shelter and food. It is an incredibly simple way to catch 22. Your new shelter is selective in the choice of birds that it will house. Singing birds seem to value the places most. Other predators may follow. At least in late autumn and early winter the energy rich power food is a welcome addition of the diet. Nesting in spring and summer might be another option to have more birds again. We shall need many very small steps again to keep biodiversity or bring back some of it. Birds again is a small initiative.

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On Organics

Organics are the new hype. Organics are everywhere. It is true in organic chemistry, biochemistry or pharmaceutical biochemistry we start from organic compounds as the basis for various forms of classification systems, structures and reaction chains. A search for organics brings you to Organic Farming and to lots of other applications of organic production as well as organic design.
The extended definitions highlight the foundation in biology and chemistry to then include any processes which integrate cyclical reproduction or resources and conservation of biodiversity. Based on the plurality of forms and connectivity of organic compounds this leads to a vast and diversified basis of carbon- and hydrogen-based life on earth. The ensuing complexity (variety of species) has been the basis for mankind to come into being. It is likely to determine also our survival in the long run. Organics is based on open as well as closed forms and therefore has an encompassing nature. Depending on time and space constellations (temporality) evolution has taken one or the other path. We are certainly not at the end of this evolution, although we through the loss of biodiversity we narrow down new potentials in an unprecedented way. Rethinking life on earth from a cell-based perspective of plastics and chloroplasts is a challenge, but it will lead us on towards the “organic turn” in the 21st century.

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Bi-directional Sleep

For most of us bi-directional sleep is a question of sleeping on the left or right side, or on our back or front, head left or right. In immunology bi-directionality of sleep has another meaning. The immune system is linked to sleep in a bi-directional manner. Good sleep enhances the immune response of cells (direction 1) and infected blood cells for example send a signal to the brain to extend sleep. The study by Huynh et al. (2024) in Nature has demonstrated this bi-directional mechanism. It allowed mice who slept well after an imposed heart attack to recover in a better way than those whose sleep got interrupted during the experiment. The most natural response to a heart attack or acute coronary syndrome is more sleep. This is induced by an inflammatory reaction in the brain, which « orders » your body to increase deep sleep. 😴 Sleep is more than just rest, it may be part of healing. ❤️‍🩹 (people looking at Caspar David Friedrich „Infinite Landscapes“, exhibition Alte Nationalgalerie Berlin 2024)

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Happy Biology

At first glance happiness from a biological perspective is easy to understand. Its hormones, stupid, that regulates it all. Only problem, there are many of them that interact and, apparently, a lot depends on the right dosis and duration of exposure or deficiency. Oxytocin deficiency seems to be a corollary of anxiety and lack of pro-social behavior, potentially making people less happy – to put it bluntly. There are other complex interactions between hormones not only in the circadian circle of humans like for cortisol, but also related to differential reactions to stress. Genetics and epigenetics are involved as well stress regulation and early exposition to stress during the life course has longer lasting consequences later on. How much stress is good for you? Climbing Mountains induces physical stress, but most people report lasting happiness referring back to such singular events. Hormones seem to play tricks with us as well.
Some time after the novel “Klara and the Sun“, endocrinologists have documented the positive effect of a robot on oxytocin levels in humans. Improvements to mental health and well-being are apparently easy considering that oxytocin is a driver of feeling happy as well. Maybe we should take our depressors and drivers of oxytocin more seriously to be “biologically” happy.
(Image: Extrait Frans Hals 1660, Catharina Hooft and her nurse. Exhibition Gemäldegalerie Berlin 2024)