transitional fossil
Between-species specimen
A transitional fossil preserves features intermediate between an ancestral group and its descendants, showing evolutionary change in progress.
Archaeopteryx, with both dinosaur and bird characteristics, is a classic example.
Creationists sometimes claim transitional fossils don't exist; paleontologists point to numerous specimens documenting major evolutionary transitions: fish to amphibians, reptiles to mammals, land mammals to whales.
- evolutionSpecies changing over generations
- natural selectionDifferential reproductive success
- ancestorPredecessor in lineage
- ArchaeopteryxPrehistoric transitional flying creature
- walking fishAquatic animal with locomotion
species · adaptation · gradual change · dinosaur · bird · fish · amphibian · skeleton · bones · discovery · Darwin · tree of life · common ancestor · paleontology · excavation · ancient · deep time · limestone
- fossilsdinosaur bones, ammonite, amber, ammonites, brachiopod
- phylogeneticscladogram, clade, phylogeny, phylogenetics, cladistics
transition, transitionally, transit, transitive, transitivity, intransitive, transitory, fossil, fossils