The major transitions in evolution: What has driven them?

1998 ◽  
Vol 13 (5) ◽  
pp. 199-200
Author(s):  
Tibor Jenny
Keyword(s):  
Major Transitions ◽  
Major Transitions In Evolution

scholarly journals Evolution of simple multicellularity increases environmental complexity

2016 ◽  
Author(s):  
María Rebolleda-Gómez ◽  
William C. Ratcliff ◽  
Jonathon Fankhauser ◽  
Michael Travisano
Keyword(s):  
Fluid Dynamics ◽  
Saccharomyces Cerevisiae ◽  
Experimental Evolution ◽  
Single Cells ◽  
Environmental Complexity ◽  
Major Transitions ◽  
Rapid Diversification ◽  
Ecological Mechanisms ◽  
Major Transitions In Evolution ◽  
Maintenance Of Diversity

AbstractMulticellularity—the integration of previously autonomous cells into a new, more complex organism—is one of the major transitions in evolution. Multicellularity changed evolutionary possibilities and facilitated the evolution of increased complexity. Transitions to multicellularity are associated with rapid diversification and increased ecological opportunity but the potential mechanisms are not well understood. In this paper we explore the ecological mechanisms of multicellular diversification during experimental evolution of the brewer’s yeast, Saccharomyces cerevisiae. The evolution from single cells into multicellular clusters modifies the structure of the environment, changing the fluid dynamics and creating novel ecological opportunities. This study demonstrates that even in simple conditions, incipient multicellularity readily changes the environment, facilitating the origin and maintenance of diversity.

4. Levels of selection

2019 ◽  
pp. 45-62
Author(s):  
Samir Okasha
Keyword(s):  
Kin Selection ◽  
Group Selection ◽  
Evolutionary Biology ◽  
Levels Of Selection ◽  
Major Transitions ◽  
Individual Level ◽  
Or Groups ◽  
The Subject ◽  
The Individual ◽  
Major Transitions In Evolution

‘Levels of selection’ examines the levels-of-selection question, which asks whether natural selection acts on individuals, genes, or groups. This question is one of the most fundamental in evolutionary biology, and the subject of much controversy. Traditionally, biologists have mostly been concerned with selection and adaptation at the individual level. But, in theory, there are other possibilities, including selection on sub-individual units such as genes and cells, and on supra-individual units such as groups and colonies. Group selection, altruistic behaviour, kin selection, the gene-centric view of evolution, and the major transitions in evolution are all discussed.

Origins and Early Evolution of Predation

2002 ◽  
Vol 8 ◽  
pp. 289-318 ◽  
Author(s):  
Stefan Bengtson
Keyword(s):  
Fossil Record ◽  
Cambrian Explosion ◽  
Major Transitions ◽  
Microbial Ecosystems ◽  
Life Itself ◽  
Evolutionary Event ◽  
History Of ◽  
Ultimate Result ◽  
Major Transitions In Evolution ◽  
Theoretical Considerations

Predation, in the broad sense of an organism killing another organism for nutritional purposes, is probably as old as life itself and has originated many times during the history of life. Although little of the beginnings is caught in the fossil record, observations in the rock record and theoretical considerations suggest that predation played a crucial role in some of the major transitions in evolution. The origin of eukaryotic cells, poorly constrained to about 2.7 Ga by geochemical evidence, was most likely the ultimate result of predation among prokaryotes. Multicellularity (or syncytiality), as a means of acquiring larger size, is visible in the fossil record soon after 2 Ga and is likely to have been mainly a response to selective pressure from predation among protists. The appearance of mobile predators on bacteria and protists may date back as far as 2 Ga or it may be not much older than the Cambrian explosion, or about 600 Ma. The combined indications from the decline of stromatolites and the diversification of acritarchs, however, suggest that such predation may have begun around 1 Ga. The Cambrian explosion, culminating around 550 Ma, represents the transition from simple, mostly microbial, ecosystems to ones with complex food webs and second- and higher-order consumers. Macrophagous predators were involved from the beginning, but it is not clear whether they originated in the plankton or in the benthos. Although predation was a decisive selective force in the Cambrian explosion, it was a shaper rather than a trigger of this evolutionary event.

scholarly journals Relatedness and the fraternal major transitions

2000 ◽  
Vol 355 (1403) ◽  
pp. 1647-1655 ◽  
Author(s):  
David C. Queller
Keyword(s):  
Kin Selection ◽  
Germ Line ◽  
Division Of Labour ◽  
Major Transitions ◽  
Insect Societies ◽  
Reproductive Division Of Labour ◽  
Special Relationships ◽  
Reproductive Division ◽  
Major Transitions In Evolution

Many of the major transitions in evolution involved the coalescence of independent lower–level units into a higher organismal level. This paper examines the role of kinship, focusing on the transitions to multicellularity in animals and to coloniality in insects. In both, kin selection based on high relatedness permitted cooperation and a reproductive division of labour. The higher relatedness of haplodiploid females to their sisters than to their offspring might not have been crucial in the origin of insect societies, and the transition to multicellularity shows that such special relationships are not required. When multicellular forms develop from a single cell, selfish conflict is minimal because each selfish mutant obtains only one generation of within–individual advantage in a chimaera. Conditionally expressed traits are particularly immune to within–individual selfishness because such mutations are rarely expressed in chimaeras. Such conditionally expressed altruism genes lead easily to the evolution of the soma, and the germ line might simply be what is left over. In most social insects, differences in relatedness ensure that there will be potential conflicts. Power asymmetries sometimes lead to such decisive settlements of conflicts that social insect colonies can be considered to be fully organismal.

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