Jaws evolved from the___
1st gill arch
Jaws evolved from the ancient lineage of cartilaginous fishes known as chondrichthyans (subclass Chondrichthyes). These fishes are characterized by their cartilaginous skeletons, five to seven pairs of gill slits, and placoid scales (also called dermal denticles or “skin teeth”). The earliest known chondrichthyan fossils date back to the Silurian period, approximately 420 million years ago. The evolution of jaws in these fishes allowed them to become top predators in the aquatic environment, with some species growing to enormous sizes and becoming apex predators in their ecosystems.
More Answers:
Discovering the Marvels of Chondrichthyes: Adaptations, Teeth and Unique Senses of Cartilaginous FishEvolution of the Second Gill Arch in Vertebrate Animals: Diverse and Complex Transformations.
Evolutionary significance of branchial arches in the development of vertebrates’ feeding strategies and respiratory systems
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