Why it is that animals, instead of developing in a simple…
“Why it is that animals, instead of developing in a simple and straightforward way, undergo in the course of their growth a series of complicated changes, during which they often acquire organs which have no function, and which, after remaining visible for a short time, disappear without leaving a trace ... To the Darwinian, the explanation of such facts is obvious. The stage when the tadpole breathes by gills is a repetition of the stage when the ancestors of the frog had not advanced in the scale of development beyond a fish.”
About This Quote
This interpretation was drafted with AI assistance. It is one reading of the quote, not the author's own explanation.
Organisms often develop temporary structures that later disappear, reflecting evolutionary history and non‑adaptive traits.
In simple terms: Temporary organs show evolutionary leftovers.
Key Takeaway
Recognize that not all traits are purposeful.
Themes
evolution
development
biology
history
adaptation
Mood
curious
analytical
Type
scientific
educational
When to use this quote
- education
- research
- biology class
- evolutionary studies
- understanding anatomy
Key Concepts
phylogeny
ontogeny
vestigiality
Questions to Reflect On
- Why do some vestigial features remain visible?
- How does this inform our view of progress?
A Different Perspective
Such structures may persist longer than expected, confusing functional analysis.