First fish: jawless swimmers that gave us backbones
Jawless fish swam 530 million years ago in China, inventing the backbone, skull and paired senses we still carry.
Tiny filter feeders in Cambrian seas
Around 530 million years ago Haikouichthys and Myllokunmingia swam in Chinese seas, only 3 centimeters long, with a head, eyes, gills and a flexible notochord forerunner of the backbone.
They had no jaws or paired fins and sucked detritus like modern lancelets, yet carried a skull case, muscle blocks and a heart, the basic vertebrate toolkit in miniature.
Armor, backbones and the coming jaws
By 450 million years ago ostracoderms wore bony head shields up to 40 centimeters long against giant sea scorpions 2 meters long, while true vertebrae replaced the notochord for stronger swimming.
Jaws evolved around 420 million years ago from front gill arches, letting fish bite and hunt, and all 65000 living vertebrates from sharks to humans keep this ancient fish body plan.
- Oldest fish are 530 million years old in Yunnan China.
- First fish were only 3 cm long without jaws.
- Ostracoderms wore bone armor 40 cm long.
- Backbone replaced notochord for power.
- Jaws appeared 420 million years ago from gills.