Transcript Sponges and Cnidarians

Sponges (Phylum Porifera)
and Cnidarians
By: Brie Clark
Sponges
• Sponges
• )No definite symmetry.
2)Body multicellular, few tissues, no organs.
3)Cells and tissues surround a water filled space but there is no true
body cavity.
4)All are sessile, (live attached to something as an adult).
5)Reproduce sexually or asexually, sexual reproduction can be either
gonochoristic or hermaphroditic.
6)Has no nervous system.
7)Has a distinct larval stage which is planktonic.
8)Lives in aquatic environments, mostly marine.
9)All are filter feeders.
10)Often have a skeleton of spicules.
Sponges
• Sponges live
•
permanently
connected to one spot
in the water
Sponges have two
layers on their body
– Acellular (having no
cells)
– Mesohyl (gel layer)
Sponges Cont.
• Sponges have three
different types of body
plans
– Asconoid= Sponges
look more like a tube
and perforated by pores
– Syconoid= Sponges
are bigger than
Asconiod, only one
opening to the outside
– Leuconoid= Biggest
and most complex,
water moves through
Sponges Cont.
• There are 5,000 to 10,000 know species
of sponges
• Most sponges live in salt water, and only
about 150 live in fresh water
• They say that sponges evolved over 500
years ago
Glass Sponges
• Glass sponges were
know to be extinct
– Found recently
• Glass sponges made
•
•
out of silica
They help build the
reef
Found in protected
Canadian waters
Glass Sponges Cont.
• Are now found in
many parts of the
ocean.
– Different than the
ones that build on the
reef
Cnidaria
• Cnidaria includes:
– Sea anemones, corals, jellyfish, sea pens,
hydra
• Sea anemones= considered to be the
flower of the sea
– Look like plants, eat meat
– Attaches to rock and coral
– Usually stay in one spot whole life
Cnidarians
• They are radially symmetrical
• Medusa is a free swimming structure
• The medusa layer is thick and jelly-like
– Most associated with jelly fish
• Some cnidarians only show the medusa
stage throughout their life
• Others first pass through other stages
before maturing into the medusa form
JellyFish
• Jellyfish have reproductive parts called
gonads
– Just like humans
• Males produce sperm
• Females produce an egg
• Tentacles of a jellyfish have cnidocytes
embedded in them
– They are specialized cells
• No other organism has them
Sea Pen
• Looks like an old-fashioned quill pen
– Colors
• Dark orange
• Yellow
• White
• Colony of polyps
– Work together to live

A polyp is a sessile that attaches to the sea floor and forms
large sea colonies
• Some cnidarians stay a polyp for their whole life
Sea Pens Cont.
• Predators
– Red Star
– Leather Star
– Nudibranchs (Sea Slug)
• Sea Pens are octocorals
– They each polyp has eight
tentacles
– Glow with light green light
• When Attacked
– Force out water
– Retreat to its bulbous foot
Sea Pens Cont.
• The “branches” catch plankton
• Some polyps reproduce
• Others force water in and out to ventilate
the colony
• Popular in Puget Sound/population
decreasing
Hydrozoa
• Hydra in the phylum Cnidaria
– They are a fresh water animal (Ponds and Ditches)
• Hydrozoa spend some of their life as a jellyfish
• The Hydra never go through medusoid stage
• They have three structural features
– Body built of 2 layers
– Contain 1 internal cavity
– All cells produced in the 1st or 2nd layer
• A third one isn’t made (Like an embryo)
Cnidarian Life Cycle
Sea Anenome
• The flower of the sea
• Look like plants
– Eat meat
• They spend most of their lives in one
place
– Bury themselves into mud
– Or attach to rocks
• Travel
Sea Anemone
• Attach to rocks or
•
coral
Have a central mouth
– Surrounded by
tentacles
• They wait for food to
swim by
Sea Anemone Cont.
Hitchhikers
• Sometimes they ride on a hermit crab, or
decorator crabs
• Sea Anemone can protect the crab
– Eat left over food if lost
• Some Anemones just float around in the
water