Unstable that they cannot count as genes (or units of selection)4 and the only . tive design and its selection pressures are (See Lewontin ,). But the. A unit of selection is a biological entity within the hierarchy of biological organization that is As a theoretical introduction to what is at stake vis-a-vis units of selection, Lewontin writes: The generality of the principles of natural selection means  ‎Fundamental theory · ‎Selection at each level · ‎Nucleic acid · ‎Cell. Richard Lewontin's early work on the “units” of selection initiated the conceptual and theoretical investigations that have led to the hierarchical.


Author: Jacinto Ryan
Country: Sudan
Language: English
Genre: Education
Published: 2 June 2017
Pages: 730
PDF File Size: 10.22 Mb
ePub File Size: 17.24 Mb
ISBN: 629-1-75946-398-6
Downloads: 60569
Price: Free
Uploader: Jacinto Ryan


Detailed work on two of the major techniques, the Price equation and contextual analysis, has indicated that neither approach is universally applicable, on the grounds that neither provides a proper causal decomposition in all varieties of selection Okasha Specifically, it appears that while contextual analysis may be superior in most cases of multi-level selection, the Price equation may be more the units of selection lewontin in certain cases of genic selection Okasha It is important to note that, even in the midst of deciding among the various methods for representing selection processes, these choices have consequences for the empirical adequacy of the selection models.

On this view, evolution is seen as a purely statistical phenomenon, and population genetics studies statistical relations estimated by census, and not causal relationships. Thus, the interactor problem has not been escaped, whether or not it is interpreted causally see Otsuka Interaction at a particular level involves the units of selection lewontin the presence of a trait at that level with a special relation to genic or genotypic expected success that is not reducible to interactions at a lower level.

A claim about interaction indicates only that there is an evolutionarily significant event occurring at the level in question; it says nothing about the existence of adaptations at that level.

Unit of selection - Wikipedia

As we shall see, the most common error made in interpreting many of the interactor-based approaches is that the presence of an interactor at a level is taken to imply that the interactor is also a manifestor of an adaptation at that level.

Answering this question obviously turns on what one takes the definition of replicator to be. The terms replicator and interactor will be used the units of selection lewontin this latter sense in the rest of this entry.

The revised definition of replicator corresponds more closely than the original one to a long-standing debate in genetics about how large or small a fragment of a genome ought to count as a replicating unit—something that is copied, and which can be treated separately in evolutionary theory see especially Lewontin ; Hull This debate revolves critically around the the units of selection lewontin of linkage disequilibrium and led some biologists to advocate the usage of parameters referring to the entire genome rather than to allele and genotypic frequencies in genetical models Lewontin Although this debate remains pertinent to the choice of state space of genetical model, it has been eclipsed by concerns about interactors in evolutionary genetics.

This is not to suggest that the replicator question has been solved.

JSTOR: Access Check

Work on the replicator question is part of a rich and continuing research program; it is simply no longer a large part of the units debates. This move neatly removes the replicator question from consideration.

Exactly why this move should have met with near universal acceptance is to some extent historical, however the fact that the intellectual tools largely mathematical models of the participants in the units debates were better suited to dealing with aspects the units of selection lewontin that debate other than the replicator question which requires mainly bio-chemical investigation, surely contributed to this outcome.

There is a very important class of exceptions to this general abandonment of the replicator question. Here the evolving unit the units of selection lewontin understood to be the developing system as a whole, privileging neither the replicator nor the interactor.

There has also been a profound reconception of the evolution by selection process, which has rejected the role of replicator as misconceived.

Unit of selection

On this approach, thinking in terms of reproducers incorporates development into heredity and the evolutionary process.

It also allows for both epigenetic and genetic inheritance to be dealt with within the same framework. The reproducer plays a central role, along with a hierarchy of the units of selection lewontin, in work on the units of evolutionary transition see Evolutionary Transition ; Griesemer c.


This topic concerns the major transitions of life from one level of complexity to the next, for example, the transition from unicellularity to multicellularity. On one side is the claim that there is no material overlap in the case of retroviral reproduction, and that the key is formal or informational relations Godfrey-Smith On the other side, is a view that sees material overlap due to RNA strand hybridization guiding and channeling flows of information Griesemer There is also the introduction of a notion of reproducer that involves only the copying of the units of selection lewontin property, with no substance overlapping involved Nanay Like the second view of reproducer, it appeals to the case of retroviruses having no material overlap cf.

There are two predominant interpretations of this question: Who benefits ultimately in the long term, from the the units of selection lewontin by selection process?

And who gets the benefit of possessing adaptations as a result of a selection process?