vestigial
No longer functional
Vestigial describes something that remains as a trace or remnant of what once existed more fully.
In biology, vestigial structures are body parts that have lost their original function through evolution: The human appendix is vestigial.
More broadly, vestigial applies to any feature that persists despite no longer serving its purpose: vestigial customs, vestigial authority.
Supplementary section after main text
- tailboneFused vertebrae at spine's base
- coccyxFused vertebrae forming tail
- wisdom teethFinal molars to erupt
- goosebumpsRaised skin from cold
nictitating membrane · body hair · male nipples · tonsils · adenoids · third eyelid
Pertaining to gradual biological change
- primitiveIn earliest form
- ancientVery old indeed
- primordialExisting from the start
- inheritedReceived from forebears
ancestral · phylogenetic · archaic · prehistoric · atavistic · primal · original
Minute remnant or pursue
- relicPreserved ancient object
- leftoverFood saved after meals
- remainderWhat's left over
- residueMatter left behind
echo · ghost · artifact · fossil · fragment · holdover · survival · atavism
Lacking any utility
- redundantExceeding what's needed
- degenerateDecline morally or physically
- atrophiedDeclined from underuse
- reducedMade less in amount
rudimentary · nonfunctional · useless · diminished · regressed · underdeveloped · withered · shrunken
Respiratory openings in fish
- yolk sacEmbryonic nutrient reservoir
- lanugoPrenatal body hair
- notochordEmbryonic axial support structure
- webbed fingersDigits joined by membrane
appendix
Supplementary section after main text
- tailboneFused vertebrae at spine's base
- coccyxFused vertebrae forming tail
- wisdom teethFinal molars to erupt
goosebumps · nictitating membrane · body hair · male nipples · tonsils · adenoids · third eyelid
evolutionary
Pertaining to gradual biological change
- primitiveIn earliest form
- ancientVery old indeed
- primordialExisting from the start
inherited · ancestral · phylogenetic · archaic · prehistoric · atavistic · primal · original
trace
Minute remnant or pursue
residue · echo · ghost · artifact · fossil · fragment · holdover · survival · atavism · throwback
functionless
Lacking any utility
- redundantExceeding what's needed
- degenerateDecline morally or physically
- atrophiedDeclined from underuse
reduced · rudimentary · nonfunctional · useless · diminished · regressed · underdeveloped · withered · shrunken · dormant
gill slits
Respiratory openings in fish
- Developmental GenesHox genes, deformed, labial, caudal, nanos
- unusedunused, idle, untouched, vacant, empty
- DarwinCharles Darwin, natural selection, evolution, HMS Beagle, Galapagos
- embryologyembryo, zygote, embryology, blastocyst, embryogenesis
vestigialfunctional
Able to operate correctly
developed · working · operational · useful · active
- vestigial structuresInherited features without function
- vestigial organBody part without function