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Cover of The Extended Selfish Gene
The Extended Selfish Gene
Richard Dawkins
Read: 2023
My Rating: 8.1/10
The Extended Selfish Gene by Richard Dawkins is a follow-up to his highly influential book, The Selfish Gene. Dawkins expands on his original view that genes, not individual organisms, are the fundamental unit of natural selection.

3 min read

The Extended Selfish Gene

Overview

In The Extended Selfish Gene, Richard Dawkins combines his two foundational works — The Selfish Gene (1976) and The Extended Phenotype (1982) — into a single expanded edition. The central thesis is that the gene, not the organism or the group, is the fundamental unit of natural selection. Organisms are “survival machines” — temporary vehicles that genes construct to replicate themselves. The “extended” part pushes this logic further: a gene’s phenotypic effects are not limited to the body that carries it but can reach into the environment and into other organisms.

Key Concepts

The Gene as Replicator

  • Replicators vs. vehicles: Dawkins draws a sharp distinction between replicators (entities that copy themselves with fidelity, fecundity, and longevity — i.e., genes) and vehicles (organisms that carry replicators and interact with the environment). Natural selection acts on replicators via the differential survival of vehicles.
  • Gene-level selection: Apparent altruism between organisms (e.g., alarm calls, food sharing) is explained by genes “for” altruism being favored when the beneficiary likely carries copies of the same gene (Hamilton’s kin selection / inclusive fitness).
  • Evolutionarily stable strategies (ESS): Borrowed from game theory (Maynard Smith), an ESS is a behavioral strategy that, once adopted by a population, cannot be invaded by any alternative strategy. Dawkins uses this to explain the stability of behavioral ratios like hawks vs. doves.

The Extended Phenotype

  • Phenotype beyond the body: A gene’s phenotypic expression is not confined to the organism’s own body. Beaver dams, spider webs, and caddisfly cases are all “extended phenotypes” — structures in the external world that are under genetic influence and subject to natural selection.
  • Parasite manipulation: Some parasites alter host behavior in ways that benefit the parasite’s genes (e.g., Toxoplasma making rodents attracted to cat urine, facilitating transmission). The host’s behavior is part of the parasite’s extended phenotype.
  • Action at a distance: The extended phenotype concept dissolves the boundary of the organism, suggesting that genetic influence radiates outward through causal chains — what matters is whether a gene’s effects, wherever they manifest, increase its replication.

Memes: Cultural Replicators

  • Memes as analogues of genes: Dawkins introduces the concept of memes — ideas, tunes, fashions, techniques — that replicate by imitation and are subject to variation and selection in the cultural environment.
  • Fidelity and mutation: Like genes, memes vary in their copying fidelity. Successful memes are those that are memorable, useful, or emotionally compelling — they spread not because they are “true” but because they are good at getting themselves copied.
  • Gene-meme coevolution: Human culture creates a second inheritance system that can override genetic imperatives (e.g., contraception, celibacy), demonstrating that replicator logic applies beyond DNA.

Personal Reflection

[To be added]

  • The Gene - Mukherjee provides the history Dawkins’ theoretical framework operates within
  • How Life Works - Ball pushes beyond the gene-centric view Dawkins champions — a direct counterpoint
  • I Contain Multitudes - The microbiome is a vivid example of Dawkins’ “extended phenotype”

Parent: Books

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