How Did Fish Evolve?

Life began evolving in the seas millions of years ago, leading to the first vertebrate, Haiku ixis, with a primitive backbone and skull. Over time, vertebrates developed more distinct features, but early fish lacked jaws. Jawless fish like lampreys and hagfish still exist today. Jaws evolved, leading to the divergence of jawed fish into cartilaginous fish, like sharks, and bony fish with calcified skeletons and swim bladders. Bony fish diversified, and lobe-finned fish eventually moved onto land, giving rise to all terrestrial vertebrates.

What significant evolutionary feature did the first fish, Haiku ixis, develop?

• A primitive backbone and skull

• A complex digestive system

• Advanced respiratory system

• A pair of wings

Which two ancient jawless fish still exist today?

• Sharks and rays

• Lampreys and hagfish

• Salmon and trout

• Tuna and mackerel

What evolutionary development allowed fish to revolutionize feeding and defense?

• Formation of gills

• Growth of fins

• Evolution of jaws

• Development of scales

What distinguishes cartilaginous fish from bony fish?

• Ability to live on land

• Skeleton made of cartilage

• Having a complex brain

• Presence of a swim bladder

Which group of fish was crucial in the transition of vertebrate life from water to land?

• Ray-finned fish

• Lobe-finned fish

• Cartilaginous fish

• Jawless fish