Adama Urbanka (1928-2014) poszukiwania sensu w ewolucji
Słowa kluczowe:evolution, palaeobiology, clonal organisms, graptolites
AbstraktAdam Urbanek was the leading evolutionary palaeobiologist in Poland. His main achievement was an explanation of changes in morphology of successive individuals within asexually produced clonal (that is, genetically identical) colonies of extinct pterobranch hemichordates (graptolites) by a gradient of morphogenetic factor released by the first individual of the colony. He also offered empirical evidence that evolutionary novelties may be introduced into graptolite colonies either proximally or distally. Probably the most spectacular of his observations of the fossil record was identification of collagen in the colony skeleton of graptolites, and evidence that regeneration of fragmented graptolite colonies may be treated as natural experiments done 420 million years ago, which has enabled tests of his morphogen gradient theory.