Sec 1.3

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Cnidarians

Body Structure-radial symmetry, -a central hollow cavity, -and tentacles containing stinging cells

- Polyp:

-Vase shaped body plan - Opens at the top tentacles spread out from

mouth - adapted to life attached to underwater surface - Medusa:

-Bowl shaped body plan (ex. Jellyfish ) - Mouth opened downward and tentacles trail

down - adapted for swimming life - Some Cnidarians go through both a polyp and medusa

stages during their lives.

Obtaining food

-Cnidarians use stinging cells to catch the prey they eat

Movement

-Unlike sponges, Cnidarians can move to escape danger or obtain food.

-Some have muscle –like tissue that allow movement in different ways

-Movement directed by nerve cells

Jelly fish: swim

Hydra: somersaults

Sea Anemones can shrink down

Reproduction

-Reproduce Sexually and asexually

-For Polyps budding is most common form of asexual reproduction.

-Sexual reproduction varies: both sexes within one individual or separate individuals.

-Moon Jelly life cycle

Life in a colony

-Some species of cnidarians live in a colony

-Colony: a group of many individual organisms.

-Stony corals : coral reefs

-Portuguese man of war-a colony can be so tight that it acts like a

single animal.