Q 01/05

Roughly how many living fish species are there, more than all other vertebrates combined?

A) About 3,300

B) About 12,000

C) About 33,000

D) About 130,000

Answer · why

C) About 33,000

About 96% of them are teleosts, the ray-finned group that can protrude its jaws.

Q 02/05

What is the largest living species of fish?

A) Great white shark

B) Beluga sturgeon

C) Basking shark

D) Whale shark

Answer · why

D) Whale shark

Despite its size it is a filter feeder that eats plankton, krill and small schooling fish; the largest reliably measured individual was 18.8 metres lo...

Q 03/05

Which geological period is nicknamed the 'Age of Fishes'?

A) Devonian

B) Cambrian

C) Jurassic

D) Cretaceous

Answer · why

A) Devonian

Placoderms, lobe-finned fish and early sharks all diversified then, roughly 420 to 360 million years ago.

Q 04/05

Which internal organ lets many bony fish adjust their buoyancy?

A) The gill rakers

B) The lateral line

C) The pyloric caeca

D) The swim bladder

Answer · why

D) The swim bladder

Lungs in land animals are homologous with it; some fish can even detect sound through it.

Q 05/05

What is the sensory system along a fish's flanks that detects currents and vibrations called?

A) The lateral line

B) The ampullae of Lorenzini

C) The nictitating membrane

D) The operculum

Answer · why

A) The lateral line

Blind cave fish navigate almost entirely by it.