TEDEd: The Incredible Evolution of FIsh Bodies

What does a sailfish use its spiny dorsal fin for?

• Propulsion

• Leaping out of the water

• Lifting off of the sea floor

• Braking

In fish who propel themselves using their body and tail, what is the primary purpose of fins?

• Attracting mates

• Providing lift for upward movement

• Protection and fighting

• Stabilizing and steering

Where are most body and caudal fin swimmers usually found?

• In the deep sea

• In shallow water

• In open water

• Near reefs

How do anguilliform swimmers, like eels, propel themselves?

• Using their fins to push against the water

• Using buoyancy alone

• Rotating their tails in a circular motion

• Using a wave-like motion of their bodies

What powers swimming in thunniform fishes, like tuna?

• The caudal fin

• The median fins

• The pectoral fins

• Body undulations

What is one benefit of median and paired fin swimming?

• Greater speed

• Fine-tuned movement

• More endurance for constant movement

• Walking along the sea floor

Where would you most likely find median and paired fin swimmers?

• In shallow waters or near reefs

• In the deep ocean

• In the open ocean

• In freshwater lakes and ponds.

What is the primary evolutionary dirver behind form (shape) in fish?

• Movement through the water

• Camoflauge from predators

• Attracting mates

• Circulating oxygen through their bodies

What are the two main groups of fish, based on how they propel themselves through the water? Select 2.

• Dorsal fin swimmers

• Median and paired fin swimmers

• Jet propulsion swimmers

• Body and caudal fin swimmers