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| Author | Cameron, E.Z. | ||||
| Title | Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard hypothesis: evidence for a mechanism | Type | Journal Article | ||
| Year | 2004 | Publication | Proceedings. Biological sciences / The Royal Society | Abbreviated Journal | Proc Biol Sci |
| Volume | 271 | Issue  |
1549 | Pages | 1723-1728 |
| Keywords | Age Factors; Animals; Body Constitution; *Evolution; Female; Glucose/metabolism/physiology; Litter Size; Male; Mammals/*physiology; *Models, Biological; Reproduction/physiology; Seasons; Sex Factors; *Sex Ratio; Time Factors | ||||
| Abstract | Evolutionary theory predicts that mothers of different condition should adjust the birth sex ratio of their offspring in relation to future reproductive benefits. Published studies addressing variation in mammalian sex ratios have produced surprisingly contradictory results. Explaining the source of such variation has been a challenge for sex-ratio theory, not least because no mechanism for sex-ratio adjustment is known. I conducted a meta-analysis of previous mammalian sex-ratio studies to determine if there are any overall patterns in sex-ratio variation. The contradictory nature of previous results was confirmed. However, studies that investigated indices of condition around conception show almost unanimous support for the prediction that mothers in good condition bias their litters towards sons. Recent research on the role of glucose in reproductive functioning have shown that excess glucose favours the development of male blastocysts, providing a potential mechanism for sex-ratio variation in relation to maternal condition around conception. Furthermore, many of the conflicting results from studies on sex-ratio adjustment would be explained if glucose levels in utero during early cell division contributed to the determination of offspring sex ratios. | ||||
| Address | Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa. ezcameron@zoology.up.ac.za | ||||
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| Language | English | Summary Language | Original Title | ||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0962-8452 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | PMID:15306293 | Approved | no | ||
| Call Number | refbase @ user @ | Serial | 413 | ||
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| Author | Barrett, L.; Henzi, P. | ||||
| Title | The social nature of primate cognition | Type | Journal Article | ||
| Year | 2005 | Publication | Proceedings. Biological Sciences / The Royal Society | Abbreviated Journal | Proc Biol Sci |
| Volume | 272 | Issue |
1575 | Pages | 1865-1875 |
| Keywords | Animals; Brain/anatomy & histology/*physiology; Cognition/*physiology; *Evolution; Intelligence/*physiology; Primates/*physiology; *Social Behavior | ||||
| Abstract | The hypothesis that the enlarged brain size of the primates was selected for by social, rather than purely ecological, factors has been strongly influential in studies of primate cognition and behaviour over the past two decades. However, the Machiavellian intelligence hypothesis, also known as the social brain hypothesis, tends to emphasize certain traits and behaviours, like exploitation and deception, at the expense of others, such as tolerance and behavioural coordination, and therefore presents only one view of how social life may shape cognition. This review outlines work from other relevant disciplines, including evolutionary economics, cognitive science and neurophysiology, to illustrate how these can be used to build a more general theoretical framework, incorporating notions of embodied and distributed cognition, in which to situate questions concerning the evolution of primate social cognition. | ||||
| Address | School of Biological Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK. louiseb@liv.ac.uk | ||||
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| Language | English | Summary Language | Original Title | ||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0962-8452 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | PMID:16191591 | Approved | no | ||
| Call Number | Serial | 2086 | |||
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| Author | Scheffer, M.; van Nes, E.H. | ||||
| Title | Self-organized similarity, the evolutionary emergence of groups of similar species | Type | Journal Article | ||
| Year | 2006 | Publication | Proceedings of the National Academy of Sciences of the United States of America | Abbreviated Journal | Proc. Natl. Acad. Sci. U.S.A. |
| Volume | 103 | Issue |
16 | Pages | 6230-6235 |
| Keywords | Animals; *Competitive Behavior; *Ecosystem; *Evolution; *Models, Biological | ||||
| Abstract | Ecologists have long been puzzled by the fact that there are so many similar species in nature. Here we show that self-organized clusters of look-a-likes may emerge spontaneously from coevolution of competitors. The explanation is that there are two alternative ways to survive together: being sufficiently different or being sufficiently similar. Using a model based on classical competition theory, we demonstrate a tendency for evolutionary emergence of regularly spaced lumps of similar species along a niche axis. Indeed, such lumpy patterns are commonly observed in size distributions of organisms ranging from algae, zooplankton, and beetles to birds and mammals, and could not be well explained by earlier theory. Our results suggest that these patterns may represent self-constructed niches emerging from competitive interactions. A corollary of our findings is that, whereas in species-poor communities sympatric speciation and invasion of open niches is possible, species-saturated communities may be characterized by convergent evolution and invasion by look-a-likes. | ||||
| Address | Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 8080, 6700 DD, Wageningen, The Netherlands. marten.scheffer@wur.nl | ||||
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| Language | English | Summary Language | Original Title | ||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 0027-8424 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | PMID:16585519 | Approved | no | ||
| Call Number | refbase @ user @ | Serial | 510 | ||
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| Author | Jansen, T.; Forster, P.; Levine, M.A.; Oelke, H.; Hurles, M.; Renfrew, C.; Weber, J.; Olek, K. | ||||
| Title | Mitochondrial DNA and the origins of the domestic horse | Type | Journal Article | ||
| Year | 2002 | Publication | Proceedings of the National Academy of Sciences of the United States of America | Abbreviated Journal | Proc. Natl. Acad. Sci. U.S.A. |
| Volume | 99 | Issue |
16 | Pages | 10905-10910 |
| Keywords | Animals; Animals, Domestic/classification/*genetics; Base Sequence; DNA, Complementary; *DNA, Mitochondrial; *Evolution, Molecular; Horses/classification/*genetics; Molecular Sequence Data; Phylogeny | ||||
| Abstract | The place and date of the domestication of the horse has long been a matter for debate among archaeologists. To determine whether horses were domesticated from one or several ancestral horse populations, we sequenced the mitochondrial D-loop for 318 horses from 25 oriental and European breeds, including American mustangs. Adding these sequences to previously published data, the total comes to 652, the largest currently available database. From these sequences, a phylogenetic network was constructed that showed that most of the 93 different mitochondrial (mt)DNA types grouped into 17 distinct phylogenetic clusters. Several of the clusters correspond to breeds and/or geographic areas, notably cluster A2, which is specific to Przewalski's horses, cluster C1, which is distinctive for northern European ponies, and cluster D1, which is well represented in Iberian and northwest African breeds. A consideration of the horse mtDNA mutation rate together with the archaeological timeframe for domestication requires at least 77 successfully breeding mares recruited from the wild. The extensive genetic diversity of these 77 ancestral mares leads us to conclude that several distinct horse populations were involved in the domestication of the horse. | ||||
| Address | Biopsytec Analytik GmbH, Marie-Curie-Strasse 1, 53359 Rheinbach, Germany. jansen@biopsytec.com | ||||
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| Language | English | Summary Language | Original Title | ||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 0027-8424 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | PMID:12130666 | Approved | no | ||
| Call Number | refbase @ user @ | Serial | 772 | ||
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| Author | Lee, R.D. | ||||
| Title | Rethinking the evolutionary theory of aging: transfers, not births, shape senescence in social species | Type | Journal Article | ||
| Year | 2003 | Publication | Proceedings of the National Academy of Sciences of the United States of America | Abbreviated Journal | Proc Natl Acad Sci U S A |
| Volume | 100 | Issue |
16 | Pages | 9637-9642 |
| Keywords | Adaptation, Physiological; *Aging; Animals; *Biological Evolution; Demography; Economics; Environment; Fertility; Humans; Life Expectancy; Longevity; Models, Theoretical; Parturition; Population Dynamics; Population Growth; Reproduction | ||||
| Abstract | The classic evolutionary theory of aging explains why mortality rises with age: as individuals grow older, less lifetime fertility remains, so continued survival contributes less to reproductive fitness. However, successful reproduction often involves intergenerational transfers as well as fertility. In the formal theory offered here, age-specific selective pressure on mortality depends on a weighted average of remaining fertility (the classic effect) and remaining intergenerational transfers to be made to others. For species at the optimal quantity-investment tradeoff for offspring, only the transfer effect shapes mortality, explaining postreproductive survival and why juvenile mortality declines with age. It also explains the evolution of lower fertility, longer life, and increased investments in offspring. | ||||
| Address | Department of Demography, University of California, 2232 Piedmont Avenue, Berkeley, CA 94720-2120, USA. rlee@demog.berkeley.edu | ||||
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| Language | English | Summary Language | Original Title | ||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 0027-8424 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | PMID:12878733 | Approved | no | ||
| Call Number | Equine Behaviour @ team @ | Serial | 5465 | ||
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| Author | Shettleworth, S.J. | ||||
| Title | Taking the best for learning | Type | Journal Article | ||
| Year | 2005 | Publication | Behavioural processes | Abbreviated Journal | Behav. Process. |
| Volume | 69 | Issue |
2 | Pages | 147-9; author reply 159-63 |
| Keywords | *Algorithms; Animals; *Behavior, Animal; Decision Making; Evolution; *Learning; *Models, Theoretical | ||||
| Abstract | Examples of how animals learn when multiple, sometimes redundant, cues are present provide further examples not considered by Hutchinson and Gigerenzer that seem to fit the principle of taking the best. “The best” may the most valid cue in the present circumstances; evolution may also produce species-specific biases to use the most functionally relevant cues. | ||||
| Address | Department of Psychology, University of Toronto, Toronto, Ont., Canada M5S 3G3. shettle@psych.utoronto.ca | ||||
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| Language | English | Summary Language | Original Title | ||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 0376-6357 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | PMID:15845301 | Approved | no | ||
| Call Number | refbase @ user @ | Serial | 361 | ||
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| Author | Reluga, T.C.; Viscido, S. | ||||
| Title | Simulated evolution of selfish herd behavior | Type | Journal Article | ||
| Year | 2005 | Publication | Journal of Theoretical Biology | Abbreviated Journal | J. Theor. Biol. |
| Volume | 234 | Issue |
2 | Pages | 213-225 |
| Keywords | Selfish herd; Behavior; Evolution; Predation risk | ||||
| Abstract | Single species aggregations are a commonly observed phenomenon. One potential explanation for these aggregations is provided by the selfish herd hypothesis, which states that aggregations result from individual efforts to reduce personnel predation risk at the expense of group-mates. Not all movement rules based on the selfish herd hypothesis are consistent with observed animal behavior. Previous work has shown that herd-like aggregations are not generated by movement rules limited to local interactions between nearest neighbors. Instead, rules generating realistic herds appear to require delocalized interactions. To date, it has been an open question whether or not the necessary delocalization can emerge from local interactions under natural selection. To address this question, we study an individual-based model with a single quantitative genetic trait that controls the influence of neighbors as a function of distance. The results indicate that predation-based selection can increase the influence of distant neighbors relative to near neighbors. Our results lend support for the idea that selfish herd behavior can arise from localized movement rules under natural selection. | ||||
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| Notes | Approved | no | |||
| Call Number | refbase @ user @ | Serial | 553 | ||
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| Author | Suzuki, Y.; Toquenaga, Y. | ||||
| Title | Effects of information and group structure on evolution of altruism: analysis of two-score model by covariance and contextual analyses | Type | Journal Article | ||
| Year | 2005 | Publication | Journal of theoretical biology | Abbreviated Journal | J. Theor. Biol. |
| Volume | 232 | Issue |
2 | Pages | 191-201 |
| Keywords | *Altruism; Analysis of Variance; *Communication; Cooperative Behavior; *Evolution; Game Theory; *Group Structure; Humans; Models, Genetic; Models, Psychological; Selection (Genetics); Trust | ||||
| Abstract | An altruistic individual has to gamble on cooperation to a stranger because it does not know whether the stranger is trustworthy before direct interaction. Nowak and Sigmund (Nature 393 (1998a) 573; J. Theor. Biol. 194 (1998b) 561) presented a new theoretical framework of indirect reciprocal altruism by image scoring game where all individuals are informed about a partner's behavior from its image score without direct interaction. Interestingly, in a simplified version of the image scoring game, the evolutionarily stability condition for altruism became a similar form of Hamilton's rule, i.e. inequality that the probability of getting correct information is more than the ratio of cost to benefit. Since the Hamilton's rule was derived by evolutionarily stable analysis, the evolutionary meaning of the probability of getting correct information has not been clearly examined in terms of kin and group selection. In this study, we applied covariance analysis to the two-score model for deriving the Hamilton's rule. We confirmed that the probability of getting correct information was proportional to the bias of altruistic interactions caused by using information about a partner's image score. The Hamilton's rule was dependent on the number of game bouts even though the information reduced the risk of cooperation to selfish one at the first encounter. In addition, we incorporated group structure to the two-score model to examine whether the probability of getting correct information affect selection for altruism by group selection. We calculated a Hamilton's rule of group selection by contextual analysis. Group selection is very effective when either the probability of getting correct information or that of future interaction, or both are low. The two Hamilton's rules derived by covariance and contextual analyses demonstrated the effects of information and group structure on the evolution of altruism. We inferred that information about a partner's behavior and group structure can produce flexible pathways for the evolution of altruism. | ||||
| Address | Integrative Environmental Sciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1, Ten-Nou-Dai, Tsukuba, Ibaraki 305-8572, Japan. yukari@pe.ies.life.tsukuba.ac.jp | ||||
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| Language | English | Summary Language | Original Title | ||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 0022-5193 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | PMID:15530489 | Approved | no | ||
| Call Number | refbase @ user @ | Serial | 556 | ||
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| Author | Hamilton, W.D. | ||||
| Title | Geometry for the selfish herd | Type | Journal Article | ||
| Year | 1971 | Publication | Journal of theoretical biology | Abbreviated Journal | J. Theor. Biol. |
| Volume | 31 | Issue |
2 | Pages | 295-311 |
| Keywords | Animals; Anura; *Behavior, Animal; Breeding; Communication; Evolution; Fear; Metallurgy; *Models, Biological; Probability; Snakes; *Spatial Behavior | ||||
| Abstract | This paper presents an antithesis to the view that gregarious behaviour is evolved through benefits to the population or species. Following Galton (1871) and Williams (1964) gregarious behaviour is considered as a form of cover-seeking in which each animal tries to reduce its chance of being caught by a predator. It is easy to see how pruning of marginal individuals can maintain centripetal instincts in already gregarious species; some evidence that marginal pruning actually occurs is summarized. Besides this, simply defined models are used to show that even in non-gregarious species selection is likely to favour individuals who stay close to others. Although not universal or unipotent, cover-seeking is a widespread and important element in animal aggregation, as the literature shows. Neglect of the idea has probably followed from a general disbelief that evolution can be dysgenic for a species. Nevertheless, selection theory provides no support for such disbelief in the case of species with outbreeding or unsubdivided populations. The model for two dimensions involves a complex problem in geometrical probability which has relevance also in metallurgy and communication science. Some empirical data on this, gathered from random number plots, is presented as of possible heuristic value. |
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| Series Volume | Series Issue | Edition | |||
| ISSN | 0022-5193 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | PMID:5104951 | Approved | no | ||
| Call Number | refbase @ user @ | Serial | 771 | ||
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| Author | Thrower, W.R. | ||||
| Title | Aggression in horses | Type | Journal Article | ||
| Year | 1970 | Publication | Proceedings of the Royal Society of Medicine | Abbreviated Journal | Proc R Soc Med |
| Volume | 63 | Issue |
2 | Pages | 163-167 |
| Keywords | *Aggression; Animals; Behavior, Animal; Breeding; Evolution; *Horses; Humans; Species Specificity; Territoriality | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 0035-9157 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | PMID:5462347 | Approved | no | ||
| Call Number | refbase @ user @ | Serial | 1966 | ||
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