The Origin of Species · Chapter
On the Degree to Which Organisation Tends to Advance explained
Darwin examines whether natural selection inevitably leads to higher organisation, arguing that advancement depends on beneficial variations under specific conditions.
What happens
Darwin examines whether natural selection inevitably leads to higher organisation, arguing that advancement depends on beneficial variations under specific conditions. He discusses the difficulty of defining 'advance in organisation,' referencing Von Baer's differentiation standard and Milne Edwards' division of physiological labour. Darwin explains the persistence of lowly forms by noting that high organisation offers no advantage in simple conditions, and that natural selection does not require progressive development—only adaptation to current circumstances. He also addresses the coexistence of diverse grades of organisation within groups, as seen in vertebrates and plants.
Themes in this chapter
Natural Selection and the Struggle for Existence
Darwin clarifies that natural selection does not necessarily lead to progressive development; it only preserves variations beneficial under current conditions, explaining the persistence of lowly forms.
Adaptation and the Utilitarian Doctrine
The chapter argues that high organisation is only advantageous when it serves a creature's specific needs; in simple conditions, it may be disserviceable, leading to retrogression.
Characters to notice
- Fritz Müller
Cited for observation that the lancelet (Amphioxus) has only an anomalous annelid as companion and competitor on the barren sandy shore of South Brazil.
- Herbert Spencer
Mentioned for his proposed law that homologous units become differentiated in proportion to their relations to incident forces, as a possible explanation for the first step in advancement.
- Von Baer
His standard of advancement—amount of differentiation of parts in the adult state—is cited as the most widely applicable and best.
- Milne Edwards
His concept of the completeness of the division of physiological labour is referenced as an alternative expression for the standard of high organisation.
- Lamarck
Mentioned for his belief in an innate and inevitable tendency towards perfection, which led him to invoke spontaneous generation to explain the persistence of lowly forms.
Key passages
“Natural selection acts exclusively by the preservation and accumulation of variations, which are beneficial under the organic and inorganic conditions to which each creature is exposed at all periods of life.”
Natural selection works solely by keeping and building up variations that help an organism survive and reproduce in its environment throughout its life.
Opening statement defining the scope of natural selection in relation to advancement.
“If we take as the standard of high organisation, the amount of differentiation and specialisation of the several organs in each being when adult (and this will include the advancement of the brain for intellectual purposes), natural selection clearly leads towards this standard.”
If we measure high organisation by how much an adult's organs are specialised and differentiated—including brain development for intellect—then natural selection indeed pushes toward that goal.
Darwin adopts Von Baer's and Milne Edwards' standards to show natural selection's tendency toward specialisation.
“On our theory the continued existence of lowly organisms offers no difficulty; for natural selection, or the survival of the fittest, does not necessarily include progressive development—it only takes advantage of such variations as arise and are beneficial to each creature under its complex relations of life.”
Our theory easily explains why lowly organisms still exist: natural selection doesn't require progress; it simply uses any beneficial variations that happen to appear in each creature's particular circumstances.
Key rebuttal to the objection that lowly forms should have been replaced if natural selection always advances organisation.
