# Extinction Caused by Natural Selection explained — The Origin of Species

> Chapter companion for The Origin of Species by Charles Darwin.

## What happens

Darwin argues that natural selection, operating through the preservation of advantageous variations, inevitably leads to the extinction of less favored forms. As new species arise, they outcompete their closest relatives, causing rarity and eventual extinction, a process analogous to the replacement of older domestic breeds by improved ones.

## Themes in this chapter

### Natural Selection and the Struggle for Existence

Natural selection is the mechanism driving extinction by favoring advantageous variations and eliminating less favored forms.

### Extinction and the Succession of Forms

Extinction is a direct consequence of natural selection, as new species replace older, closely related forms through competition.

## Character check-ins

### Charles Darwin

Author and narrator, presenting the argument that natural selection causes extinction.

## Key lines

> Natural selection acts solely through the preservation of variations in some way advantageous, which consequently endure.

Natural selection works only by keeping beneficial variations, which then persist over time.

_Darwin clarifies the exclusive mechanism of natural selection._

> Rarity, as geology tells us, is the precursor to extinction.

Geology shows that becoming rare is the step before going extinct.

_Darwin links rarity to extinction using geological evidence._

> The forms which stand in closest competition with those undergoing modification and improvement, will naturally suffer most.

The species that compete most directly with the ones being improved will be the ones that suffer the most.

_Darwin identifies that close relatives face the greatest pressure from natural selection._

## Links

- HTML: https://www.betterreads.online/discover/the_origin_of_species_se/chapters/extinction-caused-by-natural-selection
- Book: https://www.betterreads.online/discover/the_origin_of_species_se
- All chapters: https://www.betterreads.online/discover/the_origin_of_species_se/chapters