1.1.2 Cnidarians

cnidarian size range

microscopic to very large

cnidarian body plan

very simple

cnidarian symmetry type

radial

Cnidocytes

stinging cells

cnidarians lack

head, respirtatory system, circulatory system

Jellyfish or

medusa

enenemy or

polyp

polyp anatomy

tentacles, mouth, gonads, column, pedal disc

medusa anatomy

manubrium, gonads, tentacles

colonial polyps

work together for feeding, defense, and reproduction

Cnidocytes (unique to cnidarians) functions

prey capture, defense, locomotion, attachment

cnidarians reproduce

asexually and sexually

asexual reproduction

buds can break off and live alone, can split into 2

sexual reproduction

inject sperm into another

4 groups of cnidarians

1)Hydroids

2) Anemones, corals and sea pens

3) Box Jellyfish

4) Jellyfish

Freshwater Jelly (Hydroid)

invasive to America

Hydra (Hydroid)

does not age

By-the-Wind Sailor (Hydroid)

photosynthetic symbionts, eat plankton, harmless to humans, hydroid colony

Portugeuse Man O' War (Hydroid)

colonial (zooids), eat fish and plankton, toxic

Sea Fan (A,C, SP)

produce calcarious house around them, slow to grow

Sea Pen

lives on ocean floor, lives in colonies

tube anemones

toxic tentacles

stony corals

reef building corals

sea wasp (box jellyfish)

tracks prey and has eyes

Irukandji (box jellyfish)

highly venemous

true jelly fish have over

200 species

moon jellyfish (true jellyfish)

common for research, sexual dysmorphism (difference between sexes)

Lion's Mane Jellyfish (true jellyfish)

tentacles up to 127 feet

two other examples of a true jellyfish

canonball jellyfish and bay nettle