A Brief History of Life and Brain Evolution

2020 ◽  
pp. 1-26
Author(s):  
Frederick L. Coolidge
Keyword(s):  
Natural Selection ◽  
Homo Sapiens ◽  
Brain Evolution ◽  
Cognitive Differences ◽  
Behavioral Features ◽  
Survival And Reproduction ◽  
History Of ◽  
The Brain ◽  
Brain Shape ◽  
Evolutionary Fitness

This chapter reviews some of the fundamentals of evolution, particularly adaptations and exaptations. Adaptations are physical or behavioral features that through natural selection aided survival and reproduction. Exaptations are physical or behavioral features that have been co-opted from their initial adaptive functions and subsequently enhanced fitness. The reuse, recycling, or redeployment of brain neurons for purposes other than their original adaption may be considered a central organizing principle of the brain. The chapter reviews the beginnings of life and presents a timeline of life through the evolution of hominins. The term hominin refers to all current and extinct relatives and ancestors of Homo sapiens, including the australopithecines and habilines, within about the last 6 million years. The chapter introduces the hypothesis that Homo sapiens survived and flourished, instead of Neandertals, Denisovans, and other hominins, because of brain shape differences, which created cognitive differences that enhanced the evolutionary fitness of Homo sapiens.

The naked ape as an evolutionary model, 50 years later

2018 ◽  
Vol 68 (3) ◽  
pp. 227-246
Author(s):  
Nico M. van Straalen
Keyword(s):  
Natural Selection ◽  
Evolutionary Biology ◽  
Evolutionary Model ◽  
Developmental Constraints ◽  
Body Hair ◽  
Product Evolution ◽  
Adaptive Explanation ◽  
History Of ◽  
Popular Texts ◽  
The Brain

AbstractEvolution acts through a combination of four different drivers: (1) mutation, (2) selection, (3) genetic drift, and (4) developmental constraints. There is a tendency among some biologists to frame evolution as the sole result of natural selection, and this tendency is reinforced by many popular texts. “The Naked Ape” by Desmond Morris, published 50 years ago, is no exception. In this paper I argue that evolutionary biology is much richer than natural selection alone. I illustrate this by reconstructing the evolutionary history of five different organs of the human body: foot, pelvis, scrotum, hand and brain. Factors like developmental tinkering, by-product evolution, exaptation and heterochrony are powerful forces for body-plan innovations and the appearance of such innovations in human ancestors does not always require an adaptive explanation. While Morris explained the lack of body hair in the human species by sexual selection, I argue that molecular tinkering of regulatory genes expressed in the brain, followed by positive selection for neotenic features, may have been the driving factor, with loss of body hair as a secondary consequence.

Introduction

Mind Shift ◽  
2021 ◽  
pp. 1-16
Author(s):  
John Parrington
Keyword(s):  
Human Brain ◽  
Past History ◽  
Good Reason ◽  
Brain Evolution ◽  
Human Mind ◽  
Basic Knowledge ◽  
Human Uniqueness ◽  
History Of ◽  
The Brain

This introductory chapter begins by providing an overview of the power of the human brain, which is displayed in the wonders of modern civilization. Despite the human brain’s capacity for such intellectual and technological feats, we still know astonishingly little about how it achieves them. This deficit in understanding is a problem not only because it means we lack basic knowledge of the biological factors that underlie our human uniqueness, but also because, for all its amazing capabilities, the human mind seems particularly prone to dysfunction. Still, some would argue there is good reason to be optimistic about the prospect of developing new and better treatments for mental disorders in the not-so-distant future. Such optimism is based on the increasing potential to study how the brain works in various important new ways thanks to recent technological innovations. The chapter then considers two overly polarised views of the human mind. Ultimately, this book argues that society radically restructures the human brain within an individual person’s lifetime, and that it has also played a central role in the past history of our species, by shaping brain evolution.

scholarly journals The colours of humanity: the evolution of pigmentation in the human lineage

2017 ◽  
Vol 372 (1724) ◽  
pp. 20160349 ◽  
Author(s):  
Nina G. Jablonski ◽  
George Chaplin
Keyword(s):  
Natural Selection ◽  
Genetic Drift ◽  
Homo Sapiens ◽  
Skin Colour ◽  
Population Bottlenecks ◽  
Melanin Pigmentation ◽  
Evolutionary Forces ◽  
History Of ◽  
Skin Coloration ◽  
Perception Function

Humans are a colourful species of primate, with human skin, hair and eye coloration having been influenced by a great variety of evolutionary forces throughout prehistory. Functionally naked skin has been the physical interface between the physical environment and the human body for most of the history of the genus Homo , and hence skin coloration has been under intense natural selection. From an original condition of protective, dark, eumelanin-enriched coloration in early tropical-dwelling Homo and Homo sapiens , loss of melanin pigmentation occurred under natural selection as Homo sapiens dispersed into non-tropical latitudes of Africa and Eurasia. Genes responsible for skin, hair and eye coloration appear to have been affected significantly by population bottlenecks in the course of Homo sapiens dispersals. Because specific skin colour phenotypes can be created by different combinations of skin colour–associated genetic markers, loss of genetic variability due to genetic drift appears to have had negligible effects on the highly redundant genetic ‘palette’ for the skin colour. This does not appear to have been the case for hair and eye coloration, however, and these traits appear to have been more strongly influenced by genetic drift and, possibly, sexual selection. This article is part of the themed issue ‘Animal coloration: production, perception, function and application’.

scholarly journals Cognitive and behavioral modernity in Homo erectus: skull globularity and hominin brain evolution

2021 ◽  
Vol 84 (4) ◽  
pp. 467-485
Author(s):  
Gary Clark ◽  
Maciej Henneberg
Keyword(s):  
Social Evolution ◽  
Brain Size ◽  
Brain Evolution ◽  
Cranial Base ◽  
Modern Human ◽  
Homo Erectus ◽  
Dietary Factors ◽  
The Brain ◽  
Brain Shape ◽  
Mastoid Region

Abstract In this article we provide evidence that evolutionary pressures altered the cranial base and the mastoid region of the temporal bone more than the calvaria in the transition from H. erectus to H. sapiens. This process seems to have resulted in the evolution of more globular skull shape – but not as a result of expansion of the brain in the parietal regions but of reduction of the cranial base and the mastoid region relative to the parietals. Consequently, we argue that expansion of the parietals seems to be unrelated to brain evolution, but is more a by-product of reduction in other regions of the skull, reduction that may be related to dietary factors. Additionally, these findings suggest that cognitive and behavioural modernity may not necessarily be dependent on brain shape. Also, it cannot be attributed to the change in brain size because H. erectus and modern human cranial capacities overlap substantially. Consequently, we suggest H. erectus possessed the full suite of cognitive adaptations characteristic of modern humans without possessing a globular skull with flared parietals. Our results also support the theory that paedomorphic morphogenesis of the skull was important in the transition from H. erectus to H. sapiens and that such changes may be related to both dietary factors and social evolution.

scholarly journals Modern human alleles differentially regulate gene expression across brain regions: implications for brain evolution

2019 ◽  
Author(s):  
Alejandro Andirkó ◽  
Cedric Boeckx
Keyword(s):  
Gene Expression ◽  
Homo Sapiens ◽  
Regulation Of Gene Expression ◽  
Brain Evolution ◽  
Brain Regions ◽  
Modern Human ◽  
High Coverage ◽  
Evolutionary Trajectory ◽  
Regulate Gene Expression ◽  
The Brain

AbstractThe availability of high-coverage genomes of our extinct relatives, the Neanderthals and Denisovans, and the emergence of large, tissue-specific databases of modern human genetic variation, offer the possibility of probing the evolutionary trajectory of heterogenous structures of great interest, such as the brain. Using the GTEx cis-eQTL dataset and an extended catalog of Homo sapiens-specific alleles relative to Neanderthals and Denisovans, we generated a dataset of nearly fixed, Homo sapiens-derived alleles that affect the regulation of gene expression across 15 brain (and brain related) structures. The list of variants obtained reveals enrichments in regions of the modern human genome showing putative signals of positive selection relative to archaic humans, and bring out the highly derived status of the cerebellum. Additionally, we complement previous literature on the expression effects of ancestral alleles in the Homo sapiens brain by pointing at a downregulation bias caused by linkage disequilibrium.

The Cooking Ape: An Interview with Richard Wrangham

2005 ◽  
Vol 5 (1) ◽  
pp. 29-37
Author(s):  
elisabeth townsend
Keyword(s):  
Social Relationships ◽  
Human Behavior ◽  
Homo Sapiens ◽  
Social Groups ◽  
Harvard University ◽  
Primate Research ◽  
Social Organizations ◽  
Cooked Food ◽  
New Research ◽  
The Brain

Humans: The Cooking Ape Perhaps the first to suggest that humans were cooking as early as 1.9 million years ago, Richard Wrangham shows through his new research and his imagination how and possibly when cooking changed humans dramatically. Wrangham, Harvard University primatologist and MacArthur Fellow, has been studying the evolution of human cooking. After 25 years of primate research at his site in Kibale, Uganda, Wrangham is best known for explaining the similarity and differences across species of primate social organizations. In Kibale, he has analyzed chimpanzees’ behavior: how it’s changed when they interact with the environment and how their social groups have evolved. In particular, he noticed how food changed their interactions with each other. Like that of chimps, human behavior has been affected by food, especially as they shifted from raw to cooked food. Moving from eating food as it was discovered to collecting edibles and cooking them altered our social relationships. Cooked food has changed Homo sapiens physically by making food more digestible thereby altering jaws, teeth, and guts, and providing more calories for more expensive organs such as the brain. Wrangham discusses when and how humans may have started using fire to cook food, what they cooked, and the transition from cooking in an outdoor fire to hearths and open ovens.

Darwinian Evolutionary Theory

2018 ◽  
Author(s):  
Michael Ruse
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Middle Class ◽  
Evolutionary Theory ◽  
Scientific Community ◽  
Homo Sapiens ◽  
Origin Of Species ◽  
Theory Of Evolution ◽  
Descent Of Man

Charles Robert Darwin, the English naturalist, published On the Origin of Species in 1859 and the follow-up work The Descent of Man in 1871. In these works, he argued for his theory of evolution through natural selection, applying it to all organisms, living and dead, including our own species, Homo sapiens. Although controversial from the start, Darwin’s thinking was deeply embedded in the culture of his day, that of a middle-class Englishman. Evolution as such was an immediate success in scientific circles, but although the mechanism of selection had supporters in the scientific community (especially among those working with fast-breeding organisms), its real success was in the popular domain. Natural selection, and particularly the side mechanism of sexual selection, were known to all and popular themes in fiction and elsewhere.

The Property Species

2020 ◽  
Author(s):  
Bart J. Wilson
Keyword(s):  
Cognitive Linguistics ◽  
Homo Sapiens ◽  
Fundamental Principle ◽  
First Century ◽  
Human Beings ◽  
Full Account ◽  
Symbolic Thought ◽  
Core Property ◽  
The Social ◽  
History Of

What is property, and why does our species happen to have it? The Property Species explores how Homo sapiens acquires, perceives, and knows the custom of property, and why it might be relevant for understanding how property works in the twenty-first century. Arguing from some hard-to-dispute facts that neither the natural sciences nor the humanities—nor the social sciences squarely in the middle—are synthesizing a full account of property, this book offers a cross-disciplinary compromise that is sure to be controversial: All human beings and only human beings have property in things, and at its core, property rests on custom, not rights. Such an alternative to conventional thinking contends that the origins of property lie not in food, mates, territory, or land, but in the very human act of creating, with symbolic thought, something new that did not previously exist. Integrating cognitive linguistics with the philosophy of property and a fresh look at property disputes in the common law, this book makes the case that symbolic-thinking humans locate the meaning of property within a thing. The provocative implications are that property—not property rights—is an inherent fundamental principle of economics, and that legal realists and the bundle-of-sticks metaphor are wrong about the facts regarding property. Written by an economist who marvels at the natural history of humankind, the book is essential reading for experts and any reader who has wondered why people claim things as “Mine!,” and what that means for our humanity.

Inbreeding reduces reproductive fitness

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Natural Selection ◽  
Inbreeding Depression ◽  
Reproductive Fitness ◽  
Heterozygote Advantage ◽  
Small Populations ◽  
Population Bottlenecks ◽  
Risk Of Extinction ◽  
Survival And Reproduction

The harmful impacts of inbreeding are generally greater in species that naturally outbreed compared to those in inbreeding species, greater in stressful than benign environments, greater for fitness than peripheral traits, and greater for total fitness compared to its individual components. Inbreeding reduces survival and reproduction (i.e., it causes inbreeding depression), and thereby increases the risk of extinction. Inbreeding depression is due to increased homozygosity for harmful alleles and at loci exhibiting heterozygote advantage. Natural selection may remove (purge) the alleles that cause inbreeding depression, especially following inbreeding or population bottlenecks, but it has limited effects in small populations and usually does not completely eliminate inbreeding depression. Inbreeding depression is nearly universal in sexually reproducing organisms that are diploid or have higher ploidies.

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