Shape of Life: Cnideria

Which group of animals was the only one to exist hundreds of millions of years ago, before the emergence of more complex creatures like Cnidarians?

• Cnidarians

• Sponges

• Fish

• Mammals

What significant biological innovations did Cnidarians introduce that are now fundamental to many animal species?

• Photosynthesis and cellular respiration

• Tentacles, a mouth, and a stomach

• Flight and advanced vocalization

• Internal skeletons and complex circulatory systems

How do Cnidarians achieve movement and control their body actions?

• Through a rigid exoskeleton and hydraulic pressure

• By relying on external water currents for propulsion

• Using two sets of muscles controlled by nerve cells

• Via a complex brain and a spinal cord

What is the primary function of nematocysts found in Cnidarians?

• To aid in photosynthesis

• For camouflage and mimicry

• To capture prey and defend against rivals using toxins

• To filter water for nutrients

What is the primary method anemones use to attack rivals during battles?

• Biting with sharp teeth

• Unleashing thousands of poisonous weapons

• Entangling rivals with long, sticky tentacles

• Ramming into opponents with their bodies

What is the main food source for coral polyps?

• Small fish

• Algae

• Plankton

• Detritus from the ocean floor

How does the Stomphia anemone escape from a sea star predator?

• It buries itself in the sand.

• It releases a cloud of ink to obscure the predator's view.

• It detaches from the rock and swims away.

• It uses its tentacles to sting and paralyze the sea star.

What major physical transformation occurred in some cnidarians, leading to the evolution of jellyfish?

• Their bodies became hardened and shell-like.

• Their cylindrical stalk transformed into a gelatinous bell.

• They developed complex internal organs for digestion.

• They grew fins and tails for faster movement.

Which Cnideria is the longest animal in the world, longer than a blue whale?

• Sea anemone
• Preya

• Moon jellyfish
• Box jellyfish

What strange adaptation does Colobonema have?

• A complex nervous system for rapid movement.
• Bioluminescences to attract mates.

• It detaches its tentacles to distract predators

• A hard shell that protects it from predators