scholarly journals Do we expect natural selection to produce rational behaviour?

2007 ◽  
Vol 362 (1485) ◽  
pp. 1531-1543 ◽  
Author(s):  
Alasdair I Houston ◽  
John M McNamara ◽  
Mark D Steer

We expect that natural selection should result in behavioural rules which perform well; however, animals (including humans) sometimes make bad decisions. Researchers account for these with a variety of explanations; we concentrate on two of them. One explanation is that the outcome is a side effect; what matters is how a rule performs (in terms of reproductive success). Several rules may perform well in the environment in which they have evolved, but their performance may differ in a ‘new’ environment (e.g. the laboratory). Some rules may perform very badly in this environment. We use the debate about whether animals follow the matching law rather than maximizing their gains as an illustration. Another possibility is that we were wrong about what is optimal. Here, the general idea is that the setting in which optimal decisions are investigated is too simple and may not include elements that add extra degrees of freedom to the situation.

2015 ◽  
Vol 282 (1806) ◽  
pp. 20150211 ◽  
Author(s):  
Gert Stulp ◽  
Louise Barrett ◽  
Felix C. Tropf ◽  
Melinda Mills

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.


Parasitology ◽  
1983 ◽  
Vol 86 (2) ◽  
pp. 335-344 ◽  
Author(s):  
D. J. Minchella ◽  
P. T. Loverde

SUMMARYA method of interrupting the life-cycle of the human blood fluke Schistosoma by increasing the proportion of genetically insusceptible intermediate host snails in natural populations was first proposed nearly 25 years ago. The method assumes that insusceptible snails will be at a selective advantage over susceptible snails when the schistosome parasite is present, and therefore natural selection will act to increase the proportion of alleles for insusceptibility. A major objection to the proposed technique is ‘If insusceptible snails are at a selective advantage, then why are they not predominant in natural populations that transmit disease?’ One explanation of this paradox is that insusceptibility may be associated with a disadvantageous character or a physiological defect. This study tests this hypothesis by measuring the relative reproductive success of susceptible and insusceptible snails under controlled conditions. Results indicate that insusceptible (unsuitable) snails are negatively affected in the presence of either susceptible snails or schistosome parasites. Furthermore, in the presence of both susceptible snails and schistosome parasites, insusceptible snails are selectively disadvantaged compared to susceptible snails. These results obtained under laboratory-controlled conditions suggest a plausible answer as to why insusceptible snails are not predominant in natural populations that transmit disease.


Author(s):  
Iain Mathieson ◽  
Felix R. Day ◽  
Nicola Barban ◽  
Felix C. Tropf ◽  
David M. Brazel ◽  
...  

AbstractIdentifying genetic determinants of reproductive success may highlight mechanisms underlying fertility and also identify alleles under present-day selection. Using data in 785,604 individuals of European ancestry, we identify 43 genomic loci associated with either number of children ever born (NEB) or childlessness. These loci span diverse aspects of reproductive biology across the life course, including puberty timing, age at first birth, sex hormone regulation and age at menopause. Missense alleles in ARHGAP27 were associated with increased NEB but reduced reproductive lifespan, suggesting a trade-off between reproductive ageing and intensity. As NEB is one component of evolutionary fitness, our identified associations indicate loci under present-day natural selection. Accordingly, we find that NEB-increasing alleles have increased in frequency over the past two generations. Furthermore, integration with data from ancient selection scans identifies a unique example of an allele—FADS1/2 gene locus—that has been under selection for thousands of years and remains under selection today. Collectively, our findings demonstrate that diverse biological mechanisms contribute to reproductive success, implicating both neuro-endocrine and behavioural influences.


2021 ◽  
pp. 136843102110497
Author(s):  
Shanyang Zhao

Natural selection is the main mechanism that drives the evolution of species, including human societies. Under natural selection, human species responds through genetic and cultural adaptations to internal and external selection pressures for survival and reproductive success. However, this theory is ineffective in explaining human societal evolution in the Holocene and a cultural selection argument has been made to remedy the theory. The present article provides a critique of the cultural selection argument and proposes an alternative conception that treats human self-selection as an emergent mechanism of human societal evolution characterized by a new type of selection pressure and a separate fitness criterion. Specifically, the evolution of human societies is divided into two major periods, each driven by a different mode of selection: natural selection acting on genes and cultures for survival and reproductive success prior to the Neolithic Revolution, and human self-selection acting on cultures – and potentially genes as well – for thrival and prosperous living after the Neolithic Revolution. The conditions for the transition from the first mode of selection to the second and the implications of this transition for social research are also discussed.


2013 ◽  
Vol 70 (2) ◽  
pp. 263-270 ◽  
Author(s):  
Melissa L. Evans ◽  
Bryan D. Neff ◽  
Daniel D. Heath

Sexual selection is recognized as an important evolutionary force in salmon. However, relatively little is known about variation in sexual selection pressures across salmon populations or the potential role of natural selection as a driver of adaptive mating patterns. Here, we examine mating behaviour and correlates of reproductive success in Chinook salmon (Oncorhynchus tshawytscha) from the Quinsam and Little Qualicum rivers in British Columbia, Canada — two populations for which we have previously found evidence of natural selection operating on major histocompatibility complex (MHC) genes. In both populations, males courted females and exhibited dominance behaviour towards other males, and the frequency of each behaviour was positively associated with reproductive success. Males were more aggressive towards females with whom they would produce offspring of low or high MHC class II diversity, and the offspring of males from the Quinsam River exhibited higher diversity at the MHC class I than expected. We discuss our results in relation to local natural selection pressures on the MHC and the potential for MHC-dependent mate choice.


2019 ◽  
Vol 81 (2) ◽  
pp. 115-119
Author(s):  
Jay Y. S. Hodgson

Students often have difficulty understanding the underpinning mechanisms of natural selection because they lack the means to directly test hypotheses within the classroom. Computer simulations are ideal platforms to allow students to manipulate variables and observe evolutionary outcomes; however, many available models solve the scenario for the users without revealing the evolutionarily significant calculations. I developed a simplified bioenergetics model of a hammerhead shark for teaching natural selection that allows the users to manipulate variables and see the impacts of modeling while solving for the evolutionary consequences. Students generate variation within the population by controlling cephalofoil widths and swimming speeds of an individual, which affect its ability to detect and capture prey at the expense of energy lost as drag from swimming. The trade-off between energy gained from successful predation and energy lost from metabolic expenditures dictates rates of reproduction. By manipulating a subset of factors that influence differential reproductive success, students gain an improved understanding of natural selection.


Author(s):  
Alasdair I. Houston ◽  
John M. McNamara ◽  
Mark D. Steer

1917 ◽  
Vol 63 (263) ◽  
pp. 488-494
Author(s):  
Charles A. Mercier

It is considerably more than a quarter of a century since I first promulgated the doctrine that madness and unsoundness of mind are not the same thing; that madness includes more than unsoundness of mind, and that unsoundness of mind very often occurs in the sane, and is, indeed, one of the most frequent disorders of the sane. This doctrine has always seemed to me as manifestly true as the doctrine of natural selection, and, like the doctrine of natural selection, needs, it appears to me, only to be stated to secure the adhesion of every reasonable mind. In fact, I have found by experience that to the immense majority of my acquaintance it does only need to be stated to secure their adherence. Nearly everyone—everyone outside the membership of this Association—to whom I have stated it, without a single exception, has, in fact, accepted as self-evident that what matters in influencing our judgment of madness or sanity is not what a man thinks or feels, but what he says or does; not his mind, but his conduct. Even within this Association the doctrine has many adherents among the younger members, for I often receive letters from them, telling me how great an assistance it has been to them; so that things are moving, and I trust that before long we shall reach the stage that I predicted in a correspondence in the British Medical Journal, when not only will the doctrine be universally admitted to be true, but also we shall all declare that we never held any other, and that any claim of mine to have originated it will be strenuously denied. However, litera scripta manet. The minute-book of the Educational Committee will show that when I urged that conduct, as being the most important factor in madness, should be systematically studied, I could not secure even a seconder. When I subsequently brought the subject forward in this Association I had not one supporter. Nor had I when I brought it before the Royal Society of Medicine three years ago. In the third edition of Dr. Craig's book on Psychological Medicine, which has just appeared, the doctrine is not so much as even mentioned, and Dr. Craig says that insanity cannot be defined. This he says in face of the fact that at the Royal Society of Medicine I showed that there are several different concepts confused under the name of insanity, and I carefully defined every one of them; nor has any one of my definitions ever been impugned. I venture to assert that if these definitions had emanated from a German source they would have been welcomed with enthusiasm and received with reverence.


Author(s):  
James A.R. Marshall

This chapter considers a simple and general model of natural selection: replicator dynamics. Many animal traits and behaviors are social, in that they affect the reproductive success not just of the animal performing the behavior, but also conspecifics. Mathematical theories based on classical natural selection, which acts on direct reproduction by individuals, are able to explain the evolution of traits that are for personal advantage. However, this leaves the problem of providing an evolutionary explanation of traits and social behaviors that appear to be personally costly to the bearer, in reproductive terms, while having effects on conspecifics such as increasing their direct reproduction. This chapter uses the replicator dynamics to illustrate the action of natural selection on social behavior, including nonadditive interactions. It considers the additive and nonadditive donation game, and other social interactions, along with public goods games, threshold public goods games, and interactions in structured populations.


Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 149 ◽  
Author(s):  
Melissa Oddie ◽  
Bjørn Dahle ◽  
Peter Neumann

The ectoparasitic mite Varroa destructor is a key factor for colony losses in European honey bee subspecies (Apis mellifera), but it is also known that some host populations have adapted to the mite by means of natural selection. The role of a shorter host brood postcapping period in reducing mite reproductive success has been investigated in other surviving subspecies, however its role in the adaptation of European honey bee populations has not been addressed. Here, we use a common garden approach to compare the length of the worker brood postcapping period in a Norwegian surviving honey bee population with the postcapping period of a local susceptible population. The data show a significantly shorter postcapping period in the surviving population for ~10% of the brood. Since even small differences in postcapping period can significantly reduce mite reproductive success, this mechanism may well contribute to natural colony survival. It appears most likely that several mechanisms acting together produce the full mite-surviving colony phenotype.


Sign in / Sign up

Export Citation Format

Share Document