Sponges- Phylum Porifera

Characteristics of Porifera:- 1)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)Lives in aquatic environments, mostly marine. 8)All are filter feeders.

Brain coral

Cnidarians Characteristics Includes marine organisms such as jelllyfish, Portuguese man-of-war, coral, sea anemone, & sea fans All carnivorous Have 2 cell layers Single opening (mouth/anus) to gastrovascular cavity where food & water enter & wastes leave; called two-way digestive system Have tentacles around mouth to pull in water & capture food

Have a simple nerve net with to help with movement & senses Sessile members include corals, sea anemones, & sea fans Have radial symmetry as adults Contain stinging cells called cnidocytes in their tentacles that contain coiled stingers called nematocysts that can shoot out & paralyze prey 

Body Forms Have 2 basic body forms ---polyp & medusa MEDUSA POLYP Polyp forms are usually sessile with upright tentacles arranged around the mouth at the top and with a thin layer of mesoglea Polyps are the asexual stage Corals, hydra, & sea anemones exist in the polyp form as adults  CORAL POLYPS Medusa forms are usually free-swimming, bell-shaped animals with tentacles that hang down around the mouth and with a thick layer of mesoglea for support Medusa are the sexual stage

medusa Polyp

Platyhelminthes The flatworms (Phylum Platyhelminthes from the Greek platy, meaning "flat" and helminth, meaning worm) simple soft-bodied invertebrate animals. they are the largest phylum of acoelomates. Flatworms are found in marine, freshwater, and even damp terrestrial environments.

Most flatworms are free-living, but many are parasitic. There are three classes: Trematoda (flukes), Cestoda (tapeworms), and Turbellaria- planarian

Flatworms---- There is no true circulatory or respiratory system, but like all other animals, flatworms do take in oxygen. Usually the digestive tract has one opening Flatworm reproduction is hermaphroditic, meaning each individual produces eggs and sperm. When two flatworms mate, they exchange sperm so both become fertilized.

Planarian - Free-living flatworm Feed on dead or slow moving organisms Pharynx- food is sucked up and digested in individual cells Have a nerve net Simple nervous system- 2 nerve cords Eyespots- detect light and dark Reproduce asexually by regeneration Reproduce sexually (hermaphrodites)

Tapeworm- Cestoda Tapeworms can grow 15 to 30 feet (9.1 m) in length. The largest tapeworms grow up to 59 feet (18 m) Most tapeworms enter humans through infected food, the same way they enter pets . Tapeworms harm their host by stealing vital nutrients, causing malnutrition and, if left untreated, can cause intestinal blockage.

The tapeworms have long, flat bodies that are divided into three sections:  the scolex, the neck and the proglottid.  The scolex contains several suckers and may have hooks.  Each proglottid contains a complete set of male and female reproductive organs that produce sex cells.  Proglottids are formed in the section at the base of the neck, with the maturing ones moving farther back as new ones are formed in front of them.  The proglottids near the end of the body form mature eggs.  As these eggs are fertilized, the zygotes in the very last segment begin to differentiate and these segments become filled with embryos.  Proglottids also contain muscles, nerves, flame cells. Proglottids may contain up to 100,000 eggs.

Tapeworms At least 125 million humans are infected with the tapeworm disease. 

Flukes---- Parasitic Embeds in organs where it feeds. Life cycle may include one , two, or more hosts.

The nematodes roundworms are one of the most common phyla of animals Reproduction is usually sexual. Males are usually smaller than females (often much smaller) and often have a characteristically bent tail for holding the female for copulation.

Nematodes commonly parasitic on humans include whipworms, hookworms, pinworms, ascarids

Pin worms Pinworms are about the length of a staple and live in the rectum of humans. While an infected person sleeps, female pinworms leave the intestines through the anus and deposit eggs on the surrounding skin. Itching around the anus Pinworm is the most common worm infection in the United States. School-age children, followed by preschoolers, have the highest rates of infection.

Trichnella…… Trichinellosis, also called trichinosis, is caused by eating raw or undercooked meat of animals infected with the larvae of a species of worm called Trichinella. Nausea, diarrhea, vomiting, fatigue, fever, and abdominal discomfort are the first symptoms of trichinellosis. Headaches, fevers, chills, cough, eye swelling, aching joints and muscle pains, itchy skin, diarrhea, or constipation follow the first symptoms.

Ascaris….

ovaries intestines

Prevention of Worms???? Wash hands Cook meat thoroughly Wash vegetables.