Scala natura

Aristotle (384-322 B.C.)

'Artificial' classification

Essentialism

Individuals are flawed representations of their 'essence' (ideal)

Vertebrates (with red blood)

Viviparous (giving birth to living individuals) vertebrates

Humans

Whales

Other mammals

Oviparous (egg laying) vertebrates

Birds

Amphibians and reptiles (but see snakes below)

Snakes

Fish

Invertebrates (without red blood)

Cephalopods

Crustacea

Insects, spiders.

Other mollusks, echinoderms.

Sponges, etc.