Phylum: Cnidaria

Most people are familiar with Cnidarians to an extent, but not as much as you'd think. The most well known Cnidarians are Jellyfish, but there are many more species of Cnidaria, each with its own special adaptations for surviving cruel ocean life as both a boneless, brainless, and literally heartless creature.

SURVIVAL ADAPTATIONS

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• Hydrostatic Skeleton, muscles held with water filled tubes.
• Coelom, holds water for skeleton
• Nematocysts for stinging prey and enemies.
• Sometimes, living in colonies like coral.
• Have cells with different purposes in different tissues, but no organs.

MAIN GROUPS

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• Jellyfish/Sea Jellies/Jellies
• Hydra
• Coral
• Sea Anenome

LIFE CYCLE

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• Can be either sexual or asexual.
• Eggs/Polyp developed more polyps.
• Medusa/Eggs produces more Medusae.
• Polyp and Medusea can produce eachother.
• Jellyfish produces sexually the most out of all cnidarians.

ENVIRONMENT

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• Water specific, no land or air Noda Rian exist.
• Most live in ocean, while some live in fresh water.
• Sometimes can be seen in crowds of hundreds of jellyfish.
• Coral is very common in Pacific waters.
• Sometimes Cnidarians can be seen in crowds of hundreds of jellyfish.

VOCABULARY

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• Coelem: A sac filled with water in the Cniadarian.
• Polyp: A stationary Cnidarian, attached to the ground and resembling a flower. Mouth is on th the top of the head and tenctacles go up.
• Medusa: A mobile Cnidarian, which moves with ocean currents and propelling itself with water. Mouth and tentacles on bottom.
• Nematocysts: The Cnidarian's stinging cells.

SPECIAL APPENDAGES

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• A Cnidarian's most powerful appendage is the tentacles, which hide the nematocysts under their looks.
• Anemone, Jellyfish, and Hydra have stinging tentacles.
• They act as passive predators, waiting for things to accidentally be caught and paralyzed.

INTERESTING FACTS

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• Clown Fish are immune to the nematocysts of anemones. This allows the two to protect eachother in a symbiotic relationship.
• A species of jellyfish known most commonly as the Immortal Jellyfish can revert back into the polyp stage when it is injured, sick, or just old, rendering it immortal.
• The man of war Jellyfish can reach lengths of 120 feet long.
• Jellyfish are considered a delicacy in some countries.
• The Great Barrier Reef is the largest coral reef in the world.

In conclusion, Cnidarians are a vast phylum with many interesting qualities, each of which plays a part in its survival.