Biological classifications Alessandro Minelli University of Padova

Classification

Biological classifications Species, the units of classification Groups within groups – characters: problems of homology – taxa: arbitrary vs. natural units – ranks, abolute or relative? Taxon names

Biological classifications Species, the units of classification Groups within groups –characters: problems of homology – taxa: arbitrary vs. natural units – ranks, abolute or relative? Taxon names

Biological classifications Species, the units of classification Groups within groups –characters: problems of homology – taxa: arbitrary vs. natural units – ranks, abolute or relative? Taxon names

The taxonomic hierarchy phylum class order family genus species subspecies

Biological classifications Species, the units of classification Groups within groups –characters: problems of homology – taxa: arbitrary vs. natural units – ranks, abolute or relative? Taxon names

P. Belon 1555 Characters: how many? which ones?

Homologue the same organ underevery variety of form and function Owen, 1843

Analogy

The origin of species (1859) Charles Darwin

Ernst Haeckel

Willi Hennig Phylogenetic systematics (1966)

Synapomorphy = shared derived character state fin limb

cladistic methods of Renaissance scholars Angelo Poliziano

monophyletic group

paraphyletic group

polyphyletic group

Biological classifications Species, the units of classification Groups within groups –characters: problems of homology – taxa: arbitrary vs. natural units – ranks, abolute or relative? Taxon names

Invertebrates Vertebrates

Protostomes Deuterostomes

Birds Reptiles

Testudinates Archosaurs Lepidosaurs

Biological classifications Species, the units of classification Groups within groups –characters: problems of homology – taxa: arbitrary vs. natural units – ranks, abolute or relative? Taxon names

absolute ranks ? Equus Conus genus

Mammals Gastropods class

Biological classifications Species, the units of classification Groups within groups –characters: problems of homology – taxa: arbitrary vs. natural units – ranks, abolute or relative? Taxon names

Biological classifications (the dark side)

Bad taxonomy can kill

Bad taxonomy can kill species

Bad taxonomy can kill thought

how many species are there?

Biological classifications