scholarly journals Brain size evolution in pipefishes and seahorses: the role of feeding ecology, life history and sexual selection

2016 ◽  
Vol 30 (1) ◽  
pp. 150-160 ◽  
Author(s):  
M. Tsuboi ◽  
A. C. O. Lim ◽  
B. L. Ooi ◽  
M. Y. Yip ◽  
V. C. Chong ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Life History ◽  
Feeding Ecology ◽  
Brain Size ◽  
Size Evolution

Brain size evolution in anurans: a review

2019 ◽  
Vol 69 (3) ◽  
pp. 265-279 ◽  
Author(s):  
Chun Lan Mai ◽  
Wen Bo Liao
Keyword(s):  
Sexual Selection ◽  
Life History ◽  
Life History Traits ◽  
Developmental Stages ◽  
Brain Size ◽  
Ecological Factors ◽  
Brain Regions ◽  
Sperm Length ◽  
Testis Size ◽  
Size Evolution

Abstract Selection pressure is an important force in shaping the evolution of vertebrate brain size among populations within species as well as between species. The evolution of brain size is tightly linked to natural and sexual selection, and life-history traits. In particular, increased environmental stress, intensity of sexual selection, and slower life history usually result in enlarged brains. However, although previous studies have addressed the causes of brain size evolution, no systematic reviews have been conducted to explain brain size in anurans. Here, we review whether brain size evolution supports the cognitive buffer hypothesis (CBH), the expensive tissue hypothesis (ETH), or the developmental cost hypothesis (DCH) by analyzing the intraspecific and/or interspecific patterns in brain size and brain regions (i.e., olfactory nerves, olfactory bulbs, telencephalon, optic tectum, and cerebellum) associated with ecological factors (habitat, diet and predator risk), sexual selection intensity, life-history traits (age at sexual maturity, mean age, longevity, clutch size and egg size, testis size and sperm length), and other energetic organs. Our findings suggest that brain size evolution in anurans supports the CBH, ETH or DCH. We also suggest future directions for studying the relationships between brain size evolution and crypsis (i.e., ordinary mucous glands in the skin), and food alteration in different developmental stages.

scholarly journals Extended parenting and the evolution of cognition

2020 ◽  
Vol 375 (1803) ◽  
pp. 20190495 ◽  
Author(s):  
Natalie Uomini ◽  
Joanna Fairlie ◽  
Russell D. Gray ◽  
Michael Griesser
Keyword(s):  
Life History ◽  
Cognitive Abilities ◽  
Cognitive Skills ◽  
Role Models ◽  
Brain Size ◽  
Social Systems ◽  
Critical Role ◽  
Human Cognition ◽  
Cultural Learning

Traditional attempts to understand the evolution of human cognition compare humans with other primates. This research showed that relative brain size covaries with cognitive skills, while adaptations that buffer the developmental and energetic costs of large brains (e.g. allomaternal care), and ecological or social benefits of cognitive abilities, are critical for their evolution. To understand the drivers of cognitive adaptations, it is profitable to consider distant lineages with convergently evolved cognitions. Here, we examine the facilitators of cognitive evolution in corvid birds, where some species display cultural learning, with an emphasis on family life. We propose that extended parenting (protracted parent–offspring association) is pivotal in the evolution of cognition: it combines critical life-history, social and ecological conditions allowing for the development and maintenance of cognitive skillsets that confer fitness benefits to individuals. This novel hypothesis complements the extended childhood idea by considering the parents' role in juvenile development. Using phylogenetic comparative analyses, we show that corvids have larger body sizes, longer development times, extended parenting and larger relative brain sizes than other passerines. Case studies from two corvid species with different ecologies and social systems highlight the critical role of life-history features on juveniles’ cognitive development: extended parenting provides a safe haven, access to tolerant role models, reliable learning opportunities and food, resulting in higher survival. The benefits of extended juvenile learning periods, over evolutionary time, lead to selection for expanded cognitive skillsets. Similarly, in our ancestors, cooperative breeding and increased group sizes facilitated learning and teaching. Our analyses highlight the critical role of life-history, ecological and social factors that underlie both extended parenting and expanded cognitive skillsets. This article is part of the theme issue ‘Life history and learning: how childhood, caregiving and old age shape cognition and culture in humans and other animals’.

scholarly journals Acrobatic Courtship Display Coevolves with Brain Size in Manakins (Pipridae)

2015 ◽  
Vol 85 (1) ◽  
pp. 29-36 ◽  
Author(s):  
Willow R. Lindsay ◽  
Justin T. Houck ◽  
Claire E. Giuliano ◽  
Lainy B. Day
Keyword(s):  
Sexual Selection ◽  
Cognitive Abilities ◽  
Brain Size ◽  
Brain Evolution ◽  
Neural Systems ◽  
Motor Behaviour ◽  
Size Evolution ◽  
Complex Motor ◽  
Display Behaviour ◽  
Selection For

Acrobatic display behaviour is sexually selected in manakins (Pipridae) and can place high demands on many neural systems. Manakin displays vary across species in terms of behavioural complexity, differing in number of unique motor elements, production of mechanical sounds, cooperation between displaying males, and construction of the display site. Historically, research emphasis has been placed on neurological specializations for vocal aspects of courtship, and less is known about the control of physical, non-vocal displays. By examining brain evolution in relation to extreme acrobatic feats such as manakin displays, we can vastly expand our knowledge of how sexual selection acts on motor behaviour. We tested the hypothesis that sexual selection for complex motor displays has selected for larger brains across the Pipridae. We found that display complexity positively predicts relative brain weight (adjusted for body size) after controlling for phylogeny in 12 manakin species and a closely related flycatcher. This evidence suggests that brain size has evolved in response to sexual selection to facilitate aspects of display such as motor, sensorimotor, perceptual, and cognitive abilities. We show, for the first time, that sexual selection for acrobatic motor behaviour can drive brain size evolution in avian species and, in particular, a family of suboscine birds.

scholarly journals The multiple contexts of brain scaling: Phenotypic integration in brain and behavioral evolution

2022 ◽  
Author(s):  
Barbara L. Finlay
Keyword(s):  
Life History ◽  
Brain Size ◽  
Brain Evolution ◽  
Phenotypic Integration ◽  
Extended Evolutionary Synthesis ◽  
Brain Mass ◽  
Mammalian Retina ◽  
General Perspective ◽  
Duration Of Development

Understanding the adaptive functions of increasing brain size have occupied scientists for decades. Here, taking the general perspective of the Extended Evolutionary Synthesis, the question of how brains change in size will be considered in two developmental frameworks. The first framework will consider the particular developmental mechanisms that control and generate brain mass, concentrating on neurogenesis in a comparative vertebrate context. The consequences of limited adult neurogenesis in mammals, and the dominating role of duration of neurogenesis for mammalian evolution will be discussed for the particular case of the teleost versus mammalian retina, and for paths of brain evolution more generally. The second framework examines brain mass in terms of life history, particularly the features of life history that correlate highly, if imperfectly, with brain mass, including duration of development to adolescence, duration of parental care, body and range size, and longevity. This covariation will be examined in light of current work on genetic causes and consequences of covariation in craniofacial bone groupings. The eventual development of a multivariate structure for understanding brain evolution which specifically integrates formerly separate layers of analysis is the ultimate goal.

Interspecific variation in relative brain size is not correlated with intensity of sexual selection in waterfowl (Anseriformes)

2008 ◽  
Vol 56 (5) ◽  
pp. 311 ◽  
Author(s):  
P.-J. Guay ◽  
A. N. Iwaniuk
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Sperm Competition ◽  
Brain Size ◽  
Interspecific Variation ◽  
Morphological Characters ◽  
Comparative Approach ◽  
Pair Bonds ◽  
Relative Brain Size

The role of sexual selection in shaping the brain is poorly understood. Although numerous studies have investigated the role of natural selection, relatively few have focussed on the role of sexual selection. Two important factors influencing the intensity of sexual selection are sperm competition and pair bonding and three different hypotheses have been proposed to explain how they could influence relative brain size. (1) The ‘extra-pair mating’ hypothesis predicts that sexual dimorphism in brain size will increase with sperm competition intensity. (2) The ‘Machiavellian intelligence’ hypothesis predicts that brain size will be larger in species with intense sperm competition. (3) The ‘relationship intelligence’ hypothesis predicts that species forming long-term pair bonds will have larger brains. We investigated sexual dimorphism in brain size and tested these three hypotheses in waterfowl by studying correlations between relative brain volume and three measures of sperm competition (testicular mass, phallus length and mating strategy) and pair-bond duration using the modern phylogenetic comparative approach. We found no evidence of sexual dimorphism in brain size in waterfowl after controlling for body mass and found no support for any of the three hypotheses. This suggests that brain size may not be sexually selected in waterfowl, despite evidence of sexual selection pressures on other morphological characters.

scholarly journals Does encephalization correlate with life history or metabolic rate in Carnivora?

2009 ◽  
Vol 6 (3) ◽  
pp. 350-353 ◽  
Author(s):  
John A. Finarelli
Keyword(s):  
Life History ◽  
Metabolic Rate ◽  
Body Mass ◽  
Litter Size ◽  
Brain Size ◽  
Recent Analysis ◽  
Size Evolution ◽  
Gestation Time ◽  
History Of ◽  
History Variable

A recent analysis of brain size evolution reconstructed the plesiomorphic brain–body size allometry for the mammalian order Carnivora, providing an important reference frame for comparative analyses of encephalization (brain volume scaled to body mass). I performed phylogenetically corrected regressions to remove the effects of body mass, calculating correlations between residual values of encephalization with basal metabolic rate (BMR) and six life-history variables (gestation time, neonatal mass, weaning time, weaning mass, litter size, litters per year). No significant correlations were recovered between encephalization and any life-history variable or BMR, arguing against hypotheses relating encephalization to maternal energetic investment. However, after correcting for clade-specific adaptations, I recovered significant correlations for several variables, and further analysis revealed a conserved carnivoran reproductive strategy, linking degree of encephalization to the well-documented mammalian life-history trade-off between neonatal mass and litter size. This strategy of fewer, larger offspring correlating with increased encephalization remains intact even after independent changes in encephalization allometries in the evolutionary history of this clade.

scholarly journals Maternal investment, life histories, and the evolution of brain structure in primates

2019 ◽  
Author(s):  
Lauren E Powell ◽  
Sally E Street ◽  
Robert A Barton
Keyword(s):  
Life History ◽  
Life Histories ◽  
Brain Size ◽  
Developmental Trajectories ◽  
Maternal Investment ◽  
Brain Evolution ◽  
Juvenile Period ◽  
Adult Lifespan ◽  
Cerebellar Function

AbstractLife history is a robust correlate of relative brain size: large-brained mammals and birds have slower life histories and longer lifespans than smaller-brained species. One influential adaptive hypothesis to account for this finding is the Cognitive Buffer Hypothesis (CBH). The CBH proposes that large brains permit greater behavioural flexibility and thereby buffer the animal from unpredictable environmental challenges, allowing reduced mortality and increased lifespan. In contrast, the Developmental Costs Hypothesis (DCH) suggests that life-history correlates of brain size reflect the extension of maturational processes needed to accommodate the evolution of large brains. The hypotheses are not mutually exclusive but do make different predictions. Here we test novel predictions of the hypotheses in primates: examining how the volume of brain components with different developmental trajectories correlate with relevant phases of maternal investment, juvenile period and post-maturational lifespan. Consistent with the DCH, structures with different allocations of growth to pre-natal versus post-natal development exhibit predictably divergent correlations with the associated periods of maternal investment and pre-maturational lifespan. Contrary to the CBH, adult lifespan is uncorrelated with either whole brain size or the size of individual brain components once duration of maternal investment is accounted for. Our results substantiate and elaborate on the role of maternal investment and offspring development in brain evolution, suggest that brain components can evolve partly independently through modifications of distinct developmental mechanisms, and imply that postnatal maturational processes involving interaction with the environment may be particularly crucial for the development of cerebellar function. They also provide an explanation for why apes have relatively extended maturation times, which relate to the relative expansion of the cerebellum in this clade.

Searching for ‘success’: generation, gender and onward migration in the Iranian diaspora

2017 ◽  
Vol 14 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Melissa Kelly
Keyword(s):  
Life History ◽  
Young Age ◽  
Onward Migration ◽  
Social Fields ◽  
Transnational Social Fields ◽  
High Level ◽  
Iranian Diaspora

This article uses the concepts of ‘transnational social fields’ and ‘habitus’ to explore the multifaceted role families play in shaping the aspirations of onward migrating youth. The article draws on biographical life history interviews conducted with the children of Iranian migrants who were raised in Sweden but moved to London, UK as adults. The findings of the study suggest that from a young age, all the participants were pressured by their parents to perform well academically, and to achieve high level careers. These goals were easier to achieve in London than in Sweden for several reasons. Interestingly, however, participants’ understandings of what constituted success and their motivations for onward migration were nuanced and varied considerably by gender. The study contributes to an understanding of the role of multi-sited transnational social fields in shaping the aspirations of migrant youths, as well as the strategies taken up by these migrants to achieve their goals.

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