Translation guide
The process by which organisms better adapted to their environment tend to survive and produce more offspring. In Japanese, this is almost always expressed with the fixed term 自然淘汰 or 自然選択.
The scientific concept in evolutionary biology
The most common and standard translation for 'natural selection' in biological contexts. Widely used in textbooks and scientific literature.
自然淘汰は進化の主要なメカニズムの一つです。
Natural selection is one of the main mechanisms of evolution.
An alternative translation, also common in academic contexts. Slightly more literal (選択 = selection).
ダーウィンは自然選択説を提唱しました。
Darwin proposed the theory of natural selection.
Applying the concept to non-biological contexts, like market competition or social dynamics
Also used metaphorically to describe survival of the fittest in business, technology, etc.
市場では自然淘汰が起こり、弱い企業は淘汰される。
In the market, natural selection occurs and weak companies are weeded out.
淘汰 (とうた) literally means 'weeding out' or 'culling', emphasizing the elimination of less fit variants. 選択 (せんたく) means 'selection' and is more neutral. Both are acceptable, but 自然淘汰 is more idiomatic and frequent.