Videos animal intro D SpongesPorifera asf porifera Chimney

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D: Sponges__Porifera. asf

porifera • Chimney sponge

Cnidaria • Feeding • Examples • Anemone eating jellyfish

Cnidaria • D: Jellyfish. asf • D: _Stingers___Cnidaria_and_Coral. asf

Platyhelminthes - Flatworms • D: Worms__Benefits_and_Problems. asf

PHYLUM PLATYHELMINTHE S

General Characteristics • They exhibit bilateral symmetry: anterior and posterior ends are different; so are the dorsal (top) and ventral (bottom) surfaces • The platyhelminths also exhibit some degree of cephalization Commonly referred to as the 'flatworms' because their bodies are dorsoventrally flattened. • They are acoelomates • This phylum (and all remaining phyla) possess 3 germ layers (=triploblastic) • The mesoderm (third germ layer) gives rise to muscles, various organ systems, and the parenchyma, a form of solid tissue containing cells and fibers

Outer Body Covering • The body of some platyhelminthes (e. g. , turbellarians) is covered by a ciliated epidermis • Epidermal cells contain rod-shaped structures called rhabdites that when released into the surrounding water, expand form a protective mucous coat around the animal • The outer body covering of other platyhelminthes (e. g. , parasitic forms) is a nonciliated tegument • The tegument is referred to as a syncytial epithelium

Organ Systems of the Platyhelminthes Digestive System • Some of the flatworms possess a digestive system, with a mouth, pharynx, and a branching intestine from which the nutrients are absorbed • The intestine, with only one opening, is a blind system

Organ Systems of the Platyhelminthes cont. Excretory System (osmoregulation) • A network of water collecting tubules adjacent to flame cells or a protonephridia • When cilia beat they move water into the tubules and out the body through pores called nephridiopores

Organ Systems of the Platyhelminthes con’t Muscular System • Below the epidermis are layers of circular and longitudinal muscle fibers; used in locomotion Nervous System • Includes: anterior cerebral ganglia, longitudinal nerve cords, and some lateral nerves • Most free living planarians and parasitic larval forms possess a variety of sensory organs (e. g. , eye spots, statocysts, rheoreceptors)

Organ Systems of the Platyhelminthes cont. Reproductive System • Most are capable of some form of asexual reproduction (e. g. , many turbellarians reproduce by fission) • Most flatworms are hermaphroditic; however, they often pair with other individuals to exchange gametes

PLATYHELMINTHES TAXONOMY

Class Turbellaria • Free-living flatworms; mostly marine organisms • Range in size from microscopic (interstitial species between sand grains) to extremely large (two feet) Locomotion • Most move by means of cilia and mucous • Muscle contractions also permit turning, twisting and folding of the body

Class Turbellaria con’t Nutrition • Turbellarians are carnivores and prey on other animals or eat dead animal remains. • Planarians have a muscular pharynx that they can insert into their prey and then pump to bring in food fragments • These animals have a highly divided gut to greatly increase the surface area for digestion and absorption Senses • They have well developed sensory structures, including eyespots, mechanoreceptors, and chemoreceptors

Class Turbellaria con’t Reproduction • Planarians are capable of asexual reproduction via fission • Also capable of regeneration; exhibit both anterior- posterior and lateral polarity • They are hermaphrodites but usually exhibit cross -fertilization • The penis of some turbellarians is modified as a hollow stylet; sperm tranfer is by hypodermic impregnation, in which the copulating partners stab each other and inject sperm

Class Trematoda • Flukes that live as parasites either on or in other organisms. • Outer body lacks cilia; tegument has a layer of glycoproteins that are important in protection and absorption • Possess 2 suckers: 1. Oral sucker which attaches to organs of the host 2. Ventral sucker or acetabulum; used to attach to host tissues

Types of Hosts • Often have complex life cycles that alternate between sexual and asexual stages. • Most require at least 2 different kinds of hosts to complete their life cycle: 1. Definitive host (primary host) • The host in which the parasite matures and reproduces (sexually) • The host in which eggs are released 2. Intermediate host • Hosts in which larval stages develop and undergo asexual reproduction • Results in an increase in the number of the individuals

General Life Cycle - Chinese liver fluke, Clonorchis sinensis • Adults live in the bile ducts of humans, dogs, and cats • There are 2 intermediate hosts: a snail and a fish • Eggs are passed out of the definitive host and hatch as ciliated larvae called miracidia • The miracidia penetrates a snail molluscan host and becomes a sporocyst • They undergo asexual reproduction producing larvae called rediae • Rediae often asexually produce more rediae, but will eventually give rise to larvae called cercariae • They leave the molluscan host and penetrate fish • They encyst in the fish tissues as the metacercaria • Consumption of infected fish results in the metacercaria excysting in the gut and migrating to the bile duct

Schistosoma • Schistosoma spp. is a common blood fluke of Southeast Asia that causes shistosomiasis • Humans are the definitive host; snails are the intermediate host • In humans its eggs ultimately penetrates and damages intestinal tissue and tissue of the bladder • A source of constant inflammation and eventually leads to deterioration of liver, spleen and other organs

Class Cestoda General Morphology • Nonciliated tegument composed of glycoprotein • The anterior region is called a scolex; often armed with suckers and hooks • Extending from the neck is a series of proglottids; contain the sex organs and eggs; no digestive system • Mature eggs released through an opening in the proglottid or leave the host when the proglottids are separated from the main body of the worm.

Beef Tapeworm, Taeniarhynchus saginatus • Definitive host humans; intermediate host cattle • Eggs are shed with human feces; infected persons defecate in a pasture and the eggs are ingested by cattle • Eggs hatch giving rise to oncosphere larvae that bore into the intestinal wall and get into the circulatory system to be transported to muscle • Here the larvae develop into the cysticercus stage (=the bladder worm) with the inverted scolex • If uncooked beef is consumed the cysticercus is freed and the scolex everts, forming the adult • Symptoms include loss of weight, chronic indigestion, diarrhea

Platyhelminthes • Blue free-living flatworm • Figi flatworm chases crab • Monsters inside me - tapeworm

Phylum Nematoda: The Roundworms

Roundworms � Common name for phylum Nematoda is roundworms. � They are among the most numerous of all animals. � A single rotting apple can contain as many as 90, 000. � Pseudocoelomates (“pseudo” = false) � No true coelom. � They do have the peritoneal cavity (or gut), but it is not lined with mesoderm.

Nematode = Thread? �Roundworms got their name nematode because they resemble a thread. �In Greek, ”nematos” actually means thread �About 20, 000 described organisms

What is a Roundworm? �Slender, unsegmented worms. �Microscopic or up to a meter in length. �Most are free-living � inhabiting soil, salt flats, aquatic sediments, and water from polar to tropical regions. �Parasitic �Live in hosts �almost every kind of plant and animal.

What is a Roundworm? � The effects of nematode infestation on crops, domestic animals, and humans make this phylum one of the most important of all parasitic animal groups. � Almost all species of vertebrates and many invertebrates serve as hosts for one or more types of parasitic nematodes.

Digestion �Unlike the platyhelminthes, nematodes have a digestive tract with two openings. �The body plan is called a “tube-within -a-tube. ” �The outer tube is the body wall and the inner tube is the digestive tract. �Food moves in one direction through the digestive tract.

Form and Function in Roundworms � Roundworms have specialized tissues and organ systems that carry out essential body function. � In general, the body systems of free-living roundworms tend to be more complex than those of parasitic forms. � Distinguishing characteristics of this phylum are their cylindrical shape, flexible nonliving cuticle, lack of motile cilia or flagella, and the muscles of their body wall run only longitudinally.

Body Covering �Outer body covering is a thick, non-cellular cuticle secreted by the underlying epidermis, or hypodermis.

Feeding � Most free-living roundworms are predators � carnivores that use grasping mouthparts and spines to catch and eat other small animals. � Some soil-dwelling and aquatic forms eat algae, fungi, or pieces of decaying matter. � Other nematodes digest the bacteria and fungi that break down dead animals and plants.

Respiration, Circulation, and Excretion �Like flatworms, roundworms exchange gases (respire) and excrete metabolic wastes like urea and ammonia through their body walls. (diffusion) �They have no internal transport system.

Response � Nematodes have simple nervous systems, consisting of several ganglia. � Several nerves extend from ganglia in the head and run the length of the body. These nerves transmit sensory information and control movement. � Roundworms have several types of sense organs.

Response �A ring of nerve tissue and ganglia are found at the anterior end of their bodies. �They have a pair of amphids �more complex sense organs that open around their heads. �They have a pair of phasmids �similar in structure as amphids, but open around the posterior end of the body.

Movement � Muscles of nematodes extend the length of their bodies. � Together with the fluid in the pseudocoelom, create a “hydrostatic skeleton. ” � A hydrostatic skeleton is the use of coelom fluid to maintain the shape of the animal and allows for movement. � Aquatic roundworms contract these muscles to move like snakes through the water. � Soil-dwelling roundworms push their way through the soil by thrashing around.

Reproduction �Roundworms reproduce sexually. �They reproduce using internal fertilization. �Female: has ovary, passes them to the uterus, where they are fertilized. �Male: Sperm cells made in the testis and stored in the vas deferens. �the male usually deposits sperm inside the female’s reproductive tract. �Over 200, 000 eggs can be deposited at once in the soil once they are fertilized.

Reproduction Cont. �Parasitic nematodes often have complex life cycles that involve two or three different hosts or several organs within a host.

Anatomy

Classes of Nematoda �Two main classes: �Class Rhabditea – they are both free-living and parasitic forms. �Class Enoplea – mostly free living, but includes some parasites.

Roundworms & Disease �Many nematodes are very important pathogens of humans and domestic animals. Some of the nematodes we will discuss: �Hookworms �Trichina Worm �Pinworms �Filarial Worms

Trichina Worm �They infect humans, hogs, rats, cats, and dogs. Hogs can become infected eating uncooked scraps of infected meat or rats. �Heavy infections can cause death but lighter infections are more common. �About 2. 4% of the U. S. population is infected, mostly lightly.

Trichinosis - cysts within the muscles are consumed (undercooked food) -- worm grows in intestine -- forms cysts in the muscles of the new host -- symptom: terrible pain in muscles

Filarial Worms � 8 species of filarial nematodes that infect humans. � About 250 million people in tropical countries are infected with Wuchereria bancrofti or Brugia malayi, which live in the lymphatic system. � They cause inflammation and blockage of the lymphatics. � Females can be as long as 100 mm and can release live young, or tiny microfilariae into the blood and lymph.

Filarial Worms cont. �Mosquitoes ingest the microfilariae when they feed. The worms develop to the infective stage while inside the mosquito and move into the mosquito bite wound when it feeds.

Filarial Worm Diseases �Filarial worms cause three main diseases in their definitive hosts: �Elephantiasis �River blindness �Dog heartworm

Ascarid Worms (common roundworm) - lives in intestine - eggs are passed out in the feces Most roundworms infect dogs, but occasionally they find their way into human hosts

Hookworms �Hookworms are so named because the anterior (head) end curves dorsally, resembling a hook. �They have large plates in their mouths that cut into the intestines so that they can suck on the host’s blood.

Hookworms cont. � Hookworms suck more blood than they can digest. A heavy infection cause anemia. � Eggs pass in feces and juveniles hatch in soil where they can live off of bacteria. � If human skin comes in contact with the soil, infective juveniles burrow through the skin to blood. � Bare foot, I think not!!!

Pinworms �Pinworms are the most common worm parasite in the U. S. , but causes little disease. �It is estimated that 30% of children and 16% of adults in the U. S. have them. �Adults live in the large intestine and cecum.

Pinworms cont. �Females, about 12 mm in length, migrate to the anal region at night and lay eggs, causing itching. �Scratching the anal region contaminates hands and bedclothes. �So how do you test for something like this?

Scotch Tape Method � Fecal examinations and finding the eggs, but eggs are often not found in feces. � Many times the female pinworm will deposit her eggs on the skin around the anus. Doctors have started using the “scotch tape method. ” � Truth is in fact stranger than fiction.

Scotch Tape Method �The scotch tape method consists of placing the sticky side of cellulose tape onto the anus overnight. �The next morning the tape is umm. . . harvested and placed under a microscope to search for eggs. �Drugs are effective against it, �all members of the family should be treated at the same time because the worms spread easily through a household.

Pinworms �Eggs develop rapidly and become infective within six hours at body temperature. �When swallowed, these eggs hatch in the anterior end of the small intestine (the duodenum) and mature in the large intestine.

Mollusks – Soft bodied • D: _Soft_Bodies___Mollusks. asf • D: Giant_Squid. asf

Echinodermata • D: _Spiny_Skinned___Echinoderms. asf

Arthropods – jointed “feet” • D: Spiders. asf • D: _Joint_Limbed___Arthropods_. asf

Arthropoda • Millipede • Crab walking Crab eating insect deathmatch mosqquito larva

Echinodermata

Digestion

Why bilateria? • Larval forms are bilateral floating in the ocean as part of the plankton • They convert to semi-radial symmetry as adults when they become benthic feeders

Support and Skeleton • Spiny skin

Why deuterstomes?

• Tubefeet • Powerpoint • weird man