scholarly journals Grandmothering and natural selection

2010 ◽  
Vol 278 (1704) ◽  
pp. 384-391 ◽  
Author(s):  
A. Friederike Kachel ◽  
L. S. Premo ◽  
Jean-Jacques Hublin
Keyword(s):  
Natural Selection ◽  
Inclusive Fitness ◽  
Human Life ◽  
Reproductive Period ◽  
Age At First Birth ◽  
Weak Selection ◽  
Wide Range ◽  
Grandmother Hypothesis ◽  
Fitness Benefits ◽  
Post Menopausal

Humans are unique among primates in that women regularly outlive their reproductive period by decades. The grandmother hypothesis proposes that natural selection increased the length of the human post-menopausal period—and, thus, extended longevity—as a result of the inclusive fitness benefits of grandmothering. However, it has yet to be demonstrated that the inclusive fitness benefits associated with grandmothering are large enough to warrant this explanation. Here, we show that the inclusive fitness benefits are too small to affect the evolution of longevity under a wide range of conditions in simulated populations. This is due in large part to the relatively weak selection that applies to women near or beyond the end of their reproductive period. However, we find that grandmothers can facilitate the evolution of a shorter reproductive period when their help decreases the weaning age of their matrilineal grandchildren. Because selection favours a shorter reproductive period in the presence of shorter interbirth intervals, this finding holds true for any form of allocare that helps mothers resume cycling more quickly. We conclude that while grandmothering is unlikely to explain human-like longevity, allocare could have played an important role in shaping other unique aspects of human life history, such as a later age at first birth and a shorter female reproductive period.

scholarly journals O brother, where art thou? Investment in siblings for inclusive fitness benefits, not father absence, predicts earlier age at menarche

2017 ◽  
Vol 13 (10) ◽  
pp. 20170464 ◽  
Author(s):  
Daniel Smith
Keyword(s):  
Inclusive Fitness ◽  
Human Life ◽  
Life History Evolution ◽  
Father Absence ◽  
Alternative Interpretation ◽  
Reproductive Age ◽  
Independent Effect ◽  
Age At Menarche ◽  
Parents And Children ◽  
Fitness Benefits

Numerous studies have indicated that father absence is associated with earlier age at menarche, with many evolutionary theories assuming that father absence is a causal factor that accelerates reproductive development. However, an alternative interpretation suggests that offspring may reproduce earlier in the presence of half- or step-siblings as the indirect fitness benefits to investing in them are lower, relative to delaying reproduction and investing in full siblings. From this perspective, father absence may perform no causal role in facilitating the onset of menarche. Using data from the Avon Longitudinal Study of Parents and Children, I find that individuals with only half- or step-siblings reach reproductive age earlier than those with only full siblings, with no independent effect of father absence. These results suggest that inclusive fitness benefits to investing in siblings, rather than father absence, may predict variation in age at menarche. These results provide a greater understanding of the adaptive mechanisms involved in reproductive decision-making, as well as potential implications for human life-history evolution and cooperative breeding more broadly.

scholarly journals Inclusive fitness for in-laws

2018 ◽  
Vol 14 (10) ◽  
pp. 20180515 ◽  
Author(s):  
M. Dyble ◽  
A. Gardner ◽  
L. Vinicius ◽  
A. B. Migliano
Keyword(s):  
Natural Selection ◽  
Inclusive Fitness ◽  
Natural World ◽  
Genetic Ancestry ◽  
Inclusive Fitness Theory ◽  
Indirect Fitness ◽  
Future Reproduction ◽  
Fitness Benefits ◽  
Related Individuals ◽  
Shared Genetic

Cooperation among kin is common across the natural world and can be explained in terms of inclusive fitness theory, which holds that individuals can derive indirect fitness benefits from aiding genetically related individuals. However, human kinship includes not only genetic kin but also kin by marriage: our affines (in-laws) and spouses. Can cooperation between these genetically unrelated kin be reconciled with inclusive fitness theory? Here, we argue that although affinal kin and spouses do not necessarily share genetic ancestry, they may have shared genetic interests in future reproduction and, as such, can derive indirect fitness benefits though cooperating. We use standard inclusive fitness theory to derive a coefficient of shared reproductive interest ( s ) that predicts altruistic investment both in genetic kin and in spouses and affines. Specifically, a behaviour that reduces the fitness of the actor by c and increases the fitness of the recipient by b will be favoured by natural selection when sb > c . We suggest that the coefficient of shared reproductive interest may provide a valuable tool for understanding not only the evolution of human kinship but also cooperation and conflict across the natural world more generally.

scholarly journals The Evolution of Bequeathal in Stable Habitats

2018 ◽  
Author(s):  
Parry M.R. Clarke ◽  
Mary Brooke Mcelreath ◽  
Brendan J. Barrett ◽  
Karen E. Mabry ◽  
Richard Mcelreath
Keyword(s):  
Natural Selection ◽  
Inclusive Fitness ◽  
Natural Populations ◽  
Theoretical Work ◽  
Empirical Literature ◽  
High Dispersal ◽  
Baseline Mortality ◽  
Fitness Benefits ◽  
Global And Local ◽  
Local Dispersal

ABSTRACTAdults sometimes disperse while philopatric offspring inherit the natal site, a pattern known as bequeathal. Despite a decades-old empirical literature, little theoretical work has explored when natural selection may favor bequeathal. We present a simple mathematical model of the evolution of bequeathal in a stable environment, under both global and local dispersal. We find that natural selection favors bequeathal when adults are competitively advantaged over juveniles, baseline mortality is high, the environment is unsaturated, and when juveniles experience high dispersal mortality. However, frequently bequeathal may not evolve, because the fitness cost for the adult is too large relative to inclusive fitness benefits. Additionally, there are many situations for which bequeathal is an ESS, yet cannot invade the population. As bequeathal in real populations appears to be facultative, yet-to-be-modeled factors like timing of birth in the breeding season may strongly influence the patterns seen in natural populations.

scholarly journals Current Wildland Fire Patterns and Challenges in Europe: A Synthesis of National Perspectives

2021 ◽  
Vol 14 ◽  
pp. 117862212110281
Author(s):  
Nieves Fernandez-Anez ◽  
Andrey Krasovskiy ◽  
Mortimer Müller ◽  
Harald Vacik ◽  
Jan Baetens ◽  
...  
Keyword(s):  
Land Use ◽  
Large Scale ◽  
Wildland Fire ◽  
Human Life ◽  
Local Analysis ◽  
Wildland Fires ◽  
Fire Statistics ◽  
Quantitative Evidence ◽  
Wide Range ◽  
Fire Patterns

Changes in climate, land use, and land management impact the occurrence and severity of wildland fires in many parts of the world. This is particularly evident in Europe, where ongoing changes in land use have strongly modified fire patterns over the last decades. Although satellite data by the European Forest Fire Information System provide large-scale wildland fire statistics across European countries, there is still a crucial need to collect and summarize in-depth local analysis and understanding of the wildland fire condition and associated challenges across Europe. This article aims to provide a general overview of the current wildland fire patterns and challenges as perceived by national representatives, supplemented by national fire statistics (2009–2018) across Europe. For each of the 31 countries included, we present a perspective authored by scientists or practitioners from each respective country, representing a wide range of disciplines and cultural backgrounds. The authors were selected from members of the COST Action “Fire and the Earth System: Science & Society” funded by the European Commission with the aim to share knowledge and improve communication about wildland fire. Where relevant, a brief overview of key studies, particular wildland fire challenges a country is facing, and an overview of notable recent fire events are also presented. Key perceived challenges included (1) the lack of consistent and detailed records for wildland fire events, within and across countries, (2) an increase in wildland fires that pose a risk to properties and human life due to high population densities and sprawl into forested regions, and (3) the view that, irrespective of changes in management, climate change is likely to increase the frequency and impact of wildland fires in the coming decades. Addressing challenge (1) will not only be valuable in advancing national and pan-European wildland fire management strategies, but also in evaluating perceptions (2) and (3) against more robust quantitative evidence.

scholarly journals Trinidadian guppies use a social heuristic that can support cooperation among non-kin

2020 ◽  
Vol 287 (1934) ◽  
pp. 20200487 ◽  
Author(s):  
Safi K. Darden ◽  
Richard James ◽  
James M. Cave ◽  
Josefine Bohr Brask ◽  
Darren P. Croft
Keyword(s):  
Poecilia Reticulata ◽  
Social Space ◽  
Inclusive Fitness ◽  
Single Point ◽  
Theoretical Work ◽  
Evolution Of Cooperation ◽  
Social Partner ◽  
Proximate Mechanisms ◽  
Cognitive Limitations ◽  
Fitness Benefits

Cooperation among non-kin is well documented in humans and widespread in non-human animals, but explaining the occurrence of cooperation in the absence of inclusive fitness benefits has proven a significant challenge. Current theoretical explanations converge on a single point: cooperators can prevail when they cluster in social space. However, we know very little about the real-world mechanisms that drive such clustering, particularly in systems where cognitive limitations make it unlikely that mechanisms such as score keeping and reputation are at play. Here, we show that Trinidadian guppies ( Poecilia reticulata ) use a ‘walk away’ strategy, a simple social heuristic by which assortment by cooperativeness can come about among mobile agents. Guppies cooperate during predator inspection and we found that when experiencing defection in this context, individuals prefer to move to a new social environment, despite having no prior information about this new social group. Our results provide evidence in non-human animals that individuals use a simple social partner updating strategy in response to defection, supporting theoretical work applying heuristics to understanding the proximate mechanisms underpinning the evolution of cooperation among non-kin.

scholarly journals Does natural selection favour taller stature among the tallest people on earth?

2015 ◽  
Vol 282 (1806) ◽  
pp. 20150211 ◽  
Author(s):  
Gert Stulp ◽  
Louise Barrett ◽  
Felix C. Tropf ◽  
Melinda Mills
Keyword(s):  
Natural Selection ◽  
Reproductive Success ◽  
The Netherlands ◽  
Child Survival ◽  
Average Height ◽  
Tall Stature ◽  
Age At First Birth ◽  
Number Of Children ◽  
The North ◽  
Rate Of Increase

The Dutch are the tallest people on earth. Over the last 200 years, they have grown 20 cm in height: a rapid rate of increase that points to environmental causes. This secular trend in height is echoed across all Western populations, but came to an end, or at least levelled off, much earlier than in The Netherlands. One possibility, then, is that natural selection acted congruently with these environmentally induced changes to further promote tall stature among the people of the lowlands. Using data from the LifeLines study, which follows a large sample of the population of the north of The Netherlands ( n = 94 516), we examined how height was related to measures of reproductive success (as a proxy for fitness). Across three decades (1935–1967), height was consistently related to reproductive output (number of children born and number of surviving children), favouring taller men and average height women. This was despite a later age at first birth for taller individuals. Furthermore, even in this low-mortality population, taller women experienced higher child survival, which contributed positively to their increased reproductive success. Thus, natural selection in addition to good environmental conditions may help explain why the Dutch are so tall.

scholarly journals Tamoxifen and oxidative stress: an overlooked connection

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nermin S. Ahmed ◽  
Marek Samec ◽  
Alena Liskova ◽  
Peter Kubatka ◽  
Luciano Saso
Keyword(s):  
Breast Cancer ◽  
Oxidative Stress ◽  
Gold Standard ◽  
Pharmacological Activities ◽  
Standard Drug ◽  
Menopausal Women ◽  
Wide Range ◽  
Post Menopausal ◽  
Apoptotic Effects ◽  
And Oxidative Stress

AbstractTamoxifen is the gold standard drug for the treatment of breast cancer in pre and post-menopausal women. Its journey from a failing contraceptive to a blockbuster is an example of pharmaceutical innovation challenges. Tamoxifen has a wide range of pharmacological activities; a drug that was initially thought to work via a simple Estrogen receptor (ER) mechanism was proven to mediate its activity through several non-ER mechanisms. Here in we review the previous literature describing ER and non-ER targets of tamoxifen, we highlighted the overlooked connection between tamoxifen, tamoxifen apoptotic effects and oxidative stress.

Larval habitats impose trait-dependent limits on the direction and rate of adult evolution in dragonflies

2021 ◽  
Vol 17 (5) ◽  
pp. 20210023
Author(s):  
Michael P. Moore
Keyword(s):  
Natural Selection ◽  
Comparative Study ◽  
Adult Stage ◽  
Larval Habitat ◽  
Adult Size ◽  
Larval Habitats ◽  
Size Evolution ◽  
Fitness Benefits ◽  
Context Dependent ◽  
Ornament Evolution

Natural selection on juveniles is often invoked as a constraint on adult evolution, but it remains unclear when such restrictions will have their greatest impact. Selection on juveniles could, for example, mainly limit the evolution of adult traits that mostly develop prior to maturity. Alternatively, selection on juveniles might primarily constrain the evolution of adult traits that experience weak or context-dependent selection in the adult stage. Using a comparative study of dragonflies, I tested these hypotheses by examining how a species’ larval habitat was related to the evolution of two adult traits that differ in development and exposure to selection: adult size and male ornamentation. Whereas adult size is fixed at metamorphosis and experiences consistent positive selection in the adult stage, ornaments develop throughout adulthood and provide context-dependent fitness benefits. My results show that species that develop in less stable larval habitats have smaller adult sizes and slower rates of adult size evolution. However, these risky larval habitats do not limit ornament expression or rates of ornament evolution. Selection on juveniles may therefore primarily affect the evolution of adult traits that mostly develop prior to maturity.

Hippocrates and Early Greek Medicine

2018 ◽  
pp. 214-232
Author(s):  
Elizabeth Craik
Keyword(s):  
Vascular System ◽  
Human Life ◽  
Medical Writing ◽  
Detailed Account ◽  
Case Histories ◽  
Hippocratic Corpus ◽  
Wide Range ◽  
The Universe ◽  
Medical Writers

The chapter surveys early Greek medicine, primarily the works attributed to Hippocrates, but also evidence for other medical writing, such as that in the Anonymus Londinensis papyrus, and in the fragments of the pre-Socratics. It is noted that the fragments of Alcmaeon indicate experience in dissection of animals, that Diogenes of Apollonia gives a detailed account of the vascular system, and that Plato has an extensive biomedical section in Timaeus. In general, early medical writers show concern with the relation of microcosm to macrocosm and of human life to the universe; also, with opposing principles (hot and cold, wet and dry, thick and thin, rare and dense) such that health is commonly seen in terms of bodily balance and avoidance of excess. The seventy or so works of the Hippocratic corpus cover a wide range of subjects, notably prognostic signs, surgery, gynecology, case histories and aphoristics lore.

Sign in / Sign up

Export Citation Format

Share Document