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Exploring the Intertidal
Check out the intertidal zone and its biodiversity!
Cnidaria
 Cnidarians
include hydroids, sea anemones, corals and jellies.
This group is more advanced than the sponges, and has a tissue level
of construction. Only two tissues layers are present: ectoderm and
endoderm. A jelly layer called mesoglea (especially noticeable in
jelly fish) is found between the epidermis and gastrodermis.
 Basic
jelllyfish structure.
Cnidarians have a true mouth and digestive cavity, but no anus.
What goes in, also must come out the same opening! Tentacles surround
the mouth opening to trap prey. These animals are usually carnivores,
eating crustaceans, molluscs and small fish. Many corals and anemones
contain symbiotic zooxanthellae (a type of cyanobacteria). The
zooxanthellae provide oxygen and some nutrition and are important
for coral reef formation.
 Cnidarians
are made unique by the present of stinging organs called nematocysts.
Nematocysts are poisonous, sticky, or barbed filaments released
from special cnidocyte cells. Nematocyst release is triggered
by chemical or tactile stimulation and they are used for defense,
food collection and some locomotion. Nematocysts are responsible
for the sticky feeling of anemones and the poisonous sting of
some jellies.
 Anthopleura
elegantissima
(Aggregating Anemone)
Description: Green tentacles with pink/purple tips.
May be solitary or in colonies.
Range: Alaska to Baja, California
Habitat: Rocks above low tide line and in tidepools
in exposed areas.
Cool Fact: Use asexual reproduction to produce large
colonies of clones! (can also reproduce sexually)
 Anthopleura
xanthogrammica
(Giant Green Anemone)
Description: disk and tentacles are green or blue-green; often
covered with pieces of shell
Range: Alaska to Panama
Habitat: Exposed, rocky shores; intertidal to 15m and deeper.
Cool Fact: Green colour comes from symbiotic cyanobacteria.
Can live for 30 years!
see also: Strawberry Anenome, and Anthopleura and Metridium pages!
 to Intertidal
Field Guide directory
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