Allometric Analysis and Brain Size

1988 ◽  
pp. 199-210 ◽  
Author(s):  
Paul H. Harvey
Keyword(s):  
Brain Size ◽  
Allometric Analysis

scholarly journals Allometric Analysis Detects Brain Size-Independent Effects of Sex and Sex Chromosome Complement on Human Cerebellar Organization

2017 ◽  
Vol 37 (21) ◽  
pp. 5221-5231 ◽  
Author(s):  
Catherine Mankiw ◽  
Min Tae M. Park ◽  
P.K. Reardon ◽  
Ari M. Fish ◽  
Liv S. Clasen ◽  
...  
Keyword(s):  
Sex Chromosome ◽  
Brain Size ◽  
Chromosome Complement ◽  
Allometric Analysis ◽  
Independent Effects

scholarly journals Allometric analysis of brain cell number in Hymenoptera suggests ant brains diverge from general trends

2021 ◽  
Vol 288 (1947) ◽  
Author(s):  
Rebekah Keating Godfrey ◽  
Mira Swartzlander ◽  
Wulfila Gronenberg
Keyword(s):  
Brain Size ◽  
Cell Number ◽  
Brain Cell ◽  
Brain Mass ◽  
Neuron Density ◽  
Cell Counts ◽  
Total Brain ◽  
Isotropic Fractionator ◽  
Cell Densities ◽  
Allometric Analysis

Many comparative neurobiological studies seek to connect sensory or behavioural attributes across taxa with differences in their brain composition. Recent studies in vertebrates suggest cell number and density may be better correlated with behavioural ability than brain mass or volume, but few estimates of such figures exist for insects. Here, we use the isotropic fractionator (IF) method to estimate total brain cell numbers for 32 species of Hymenoptera spanning seven subfamilies. We find estimates from using this method are comparable to traditional, whole-brain cell counts of two species and to published estimates from established stereological methods. We present allometric scaling relationships between body and brain mass, brain mass and nuclei number, and body mass and cell density and find that ants stand out from bees and wasps as having particularly small brains by measures of mass and cell number. We find that Hymenoptera follow the general trend of smaller animals having proportionally larger brains. Smaller Hymenoptera also feature higher brain cell densities than the larger ones, as is the case in most vertebrates, but in contrast with primates, in which neuron density remains rather constant across changes in brain mass. Overall, our findings establish the IF as a useful method for comparative studies of brain size evolution in insects.

Race differences in brain size.

1995 ◽  
Vol 50 (11) ◽  
pp. 947-948 ◽  
Author(s):  
Michael Peters
Keyword(s):  
Brain Size ◽  
Race Differences

New research frameworks in the study of chimpanzee and gorilla sociality and communication

2019 ◽  
Author(s):  
Sam G. B. Roberts ◽  
Anna Roberts
Keyword(s):  
Social Evolution ◽  
Social Complexity ◽  
Brain Size ◽  
Social Systems ◽  
Strongly Correlated ◽  
The Social ◽  
Human Social Evolution ◽  
Research Frameworks ◽  
New Research ◽  
Large Groups

Group size in primates is strongly correlated with brain size, but exactly what makes larger groups more ‘socially complex’ than smaller groups is still poorly understood. Chimpanzees (Pan troglodytes) and gorillas (Gorilla gorilla) are among our closest living relatives and are excellent model species to investigate patterns of sociality and social complexity in primates, and to inform models of human social evolution. The aim of this paper is to propose new research frameworks, particularly the use of social network analysis, to examine how social structure differs in small, medium and large groups of chimpanzees and gorillas, to explore what makes larger groups more socially complex than smaller groups. Given a fission-fusion system is likely to have characterised hominins, a comparison of the social complexity involved in fission-fusion and more stable social systems is likely to provide important new insights into human social evolution

D'Arcy Wentworth Thompson, interindividual variation, and postnatal neuronal growth

2001 ◽  
Vol 24 (2) ◽  
pp. 284-284 ◽  
Author(s):  
Terry Elliott
Keyword(s):  
Brain Size ◽  
Interindividual Variation ◽  
Statistical Techniques ◽  
Neuronal Growth ◽  
Brain Part

It is suggested that a connection between neurogenesis and brain part size is unsurprising. It is argued that neurogenesis cannot, however, be the only factor contributing to brain size. Highly individual post-natal experience radically shapes individual brains, leading to dramatic increases in brain size. The role of comparatively coarse statistical techniques in addressing these subtle biological issues is questioned.

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’.

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