Sara, JP, Yannan

Porifera and cnidarians are part of the group of animals called invertebrates, which means that they do not have a backbone.

No bones! This jellyfish does not have a bone, much less a backbone, thus making it an invertebrate.

http://arnica.csustan.edu/photos/animals/Jelly_Fish1.jpg

Sponges vary in shapes and sizes. Shown on the left is a barrel sponge, and on the right is a tube sponge.

http://www.longbeachdivers.com/photo/albums/underwater/normal_barrel-sponge.jpg

http://www.mbgnet.net/salt/animals/1sponge.jpg

Pompous Porifera

Porifera is Latin for pore-bearing, and consists of all sponges (the living ones that live in the ocean, not the ones you wash your dishes with). Early in history, sponges divided from other metazoans. Their are fossil sponges, glass sponges, and calcareous sponges. Fossil sponges are among the oldest animal fossils, glass sponges are hexactinellida, and calcareous sponges are Calcarea. No matter what kind of sponge, they do not have mouths, have specialized cells that can transform into other types, and consist of mesohyl. There are around 9,000 species of sponges, and they come in all sorts of shapes and sizes. Most are about a few centimeters in size, but shapelessor urn-shaped sponges may be less than a centimeter while vase-like, tubes, and branches can be 1-2 meters tall. Barrel sponges can have a diameter of 1-2 meters! Size also depends on age, environmental conditions, and food supply. Sponges though, are the simplest animals, and lack true tissues and organs. Their body is simply consists of two layers of cells separated by a jelly-like substance. The flagella of the collar cells make the currents need to filter water for food from the outside layer to the inside layer.

Crazy Cnidarians

Cnidarians consist of sea anemones, corals, jellyfish, and hydroids (hydras) . All cnidarians have radial symmetry and stinging cells called cnidocytes. Most cnidarians have a toxin in their stingers which often disable their prey. Cnidarian means "stinging creature". Some tentacels of a Jelly fish can be so long they can capture fish for dinner without the fish knowing. All cnidarians are carnivores, and they use their cnidocytes and toxin to capture food, but none are known to actually pursue their prey. After stinging, paralyzing, or killing their prey, it pulls its prey into a digestive sac called the gastrovascular cavity. Thousands of cnidarian species live in oceans. A smaller number of species live in rivers and fresh water lakes. Cnidarians' bodies can have one or sometimes three layers. Cnidarians have two basic forms, medusa and polyp. Medusa means free-swimming or floating, like adult Jellyfish. They have umbrella shaped like bodies and have four part symmetry. The mouth is usually on the concave side, and the tentacles rise on the rim of the umbrella. Polyp means a type of animal form characterized by a more or less fixed base.They have a tube like bodies and the mouth is usually surrounded my tentacles. Polyps may occur in groups or individually. Different individuals may specialize for different functions, such as reproduction, feeding, or defense.

sea anemone

(178).jpghttp://www.marinefoundation.org/1,1staug1%20

Amazing Anemones

Imagine if you had to spend your entire life in one place. Well, that's how most sea anemones live. Only some can move, but at a very slow pace-only 3-4 inches per hour. Some hitch a ride onto a hermit crab or a decorator crab, protecting it, which in turn receives food scraps the crab doesn't eat. Sea anemones eat small fish shrimp, isopods, amphipods, and plankton, and captures food with its stinging tentacles. Their size is usually 5-17 centimeters, and they come in all colors. They reproduce by budding off baby sea anemones which stay attached until they are old enough to go off by themselves. If a rock were to rip a sea anemone apart, each part would become an anemone. Cool, eh?

hydroids

http://www.reefs.org/library/aquarium_net/1097/images/hydracti.jpg

Hooking Hydroids

Hydroids are like stinging jellyfish attached to a base of seaweed. They are very small and most people won't notice them. When stung by a hydroid, severe, itchy welts and blisters will occur. Predators of the hydroid include sea slugs, filefishes, puffers, and the moorish idol. When a swimmer makes contact with reef, seaweed, pilings, floating docks, or debris, powerful stinging cells cause skin irritation. Hydroids are mostly either plant-like or free-swimming jellyfish-like. Plant-like hydroids reproduce asexually and have polyps, while free-swimming jellyfish-like reproduce sexually and have medusa. Simple examples include the solitary freshwater hydra which does not have any form of a skeleton. Marine hydroids usually live in colonies, and all catch prey in the water column with nematocysts that sting and grapple the prey. The two major types of hydroids are S. O. Anthomedusae and S. O. Leptomedusae. S. O. Anthomedusae do not have an exoskeleton, and S. O. Leptomedusae have exoskeleton cups that protects the polyp and specialized gonad structures.

coral

http://cybtex.de/images/gallery/big/deep-sea-coral.jpg

Captivating Coral

Corals belong to the phylum cnidaria. Other animals that belong include jellyfish, hydras, and sea anemones. They all have specialized cells called nematocysts and they exhibit radial symmetry. Corals typically form colonies consisting of many individval. Most coral colonies grow from a single founder. A coral colony consists of a base that attaches coral to a reef or upper surfaces that are exposed to light. "Coral" refers to a number of different animals. These include hard coral, sea coral, sea feathers, sea pens, sea pansies, organ pipe coral, black coral, soft coral, fan coral, and whip coral. Many corals have zooxanthellae within their tissues. Zooxanthellae are algae that form a symbiotic relationship with coral and it makes coral grow because it enables it to eat. Corals inhabit a wide range of habitates and regions. Some hard corals species are found in temperate and even polar waters that occur as far as 6,000 meters below the surface of water.

jellyfish

http://news.cnet.com/i/ne/p/2006/CnidarianClouds_400x600.jpg

Juicy Jellyfish!!!!

Jellyfish are made up of about 95% water. They have soft bodies that do not have a skeletal structures or outer shells and need water to help support their bodies. Jellyfish have radial symmetry just like other cnidarians. A jellyfish has a simple digestive system with only one openeing. They take food in from their mouth and remove waste through their mouth as well. Their mouth is located right under their bell, or umbrella. A jellyfish's body consists of three layers. Their outer layer is called the epidermis, the middle layer that consists of the thickest substance is called the mesoglea, and the inner lalyer that lines the gastrovascular cavity is called the gastrodermis. Jellyfish have no brain, no blood, and no nervous system. They have eye spots that can sense light from dark, which help jellyfish identify their prey.

Here are two cool videos about jellyfish:

http://videos.howstuffworks.com/animals/cnidarians-videos.htm

http://kids.nationalgeographic.com/kids/animals/creaturefeature/jellyfish/ (click video and sound)