Phylum Cnidarian: Stop 3 – Anenomes

Ref: Lesson 18 Marine Invertebrates

• Phylum: Cnidaria• Class: Anthozoa• Order: Actiniaria

Venus Fly Trap Anenome

Classification

General Characteristics• There are more than 1,000 sea

anemone species found throughout the world’s oceans at various depths• Largest and most varied occur in

coastal tropical waters. • They run the full spectrum of

colors

General Characteristics• Range in size from 0.5 in. - 6 feet across.• Some species of sea anemone can live 50 years

or more

• The ornately colored sea anemone (uh-NEM-uh-nee) is named after the equally flashy terrestrial anemone flower• A close relative of coral and jellyfish• Anemones are stinging polyps that spend most of their time attached

to rocks on the sea bottom or on coral reefs • Waiting for fish to pass close enough to get ensnared in their venom-

filled tentacles.

Body Plan

• Their bodies are composed of an adhesive pedal disc, or foot• Cylindrical body with radial

symmetry• Array of tentacles surrounding a

central mouth

Pedal Disc attached to substrate

Body Plan

• The tentacles are triggered by the slightest touch, firing a harpoon-like filament into their victim and injecting a paralyzing neurotoxin.• The helpless prey is then guided

into the mouth by the tentacles

Feeding

• The tentacles are triggered by the slightest touch• Fire a harpoon-like filament into their victim and injecting a paralyzing

neurotoxin.• Helpless prey is then guided into the mouth by the tentacles

Feeding postures of M. senile in current (Left) and slack water (Right)

• Some anemones, like their coral cousins, establish symbiotic relationships with green algae• In exchange for providing the algae safe harbor and exposure to

sunlight, the anemone receives oxygen and sugar, the by-products of the algae's photosynthesis.

• They form another, more famous symbiotic alliance with clownfish, which are protected by a mucus layer that makes them immune to the anemone's sting. • Clownfish live within the anemone’s tentacles, getting protection

from predators• Anemone snacks on the scraps from the clownfish’s meals.

Life

Cycl

e

• Purple sea anenome