Videos - animal

2. Videos - animal intro

5. D:\Sponges__Porifera.asf

7. porifera • Chimney sponge

8. Cnidaria • Feeding • Examples • Anemone eating jellyfish

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

12. Platyhelminthes - Flatworms • D:\Worms__Benefits_and_Problems.asf

14. Phylum Platyhelminthes

15. 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

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

17. 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

18. 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

19. 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)

20. 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

21. Platyhelminthes Taxonomy

22. 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

23. 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

24. 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

25. 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 toattach to host tissues

26. 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

27. 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

29. 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

30. Class Cestoda • General Morphology • Nonciliated tegument composed of glycoprotein • The anterior region is called a scolex; oftenarmed 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.

31. 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 larvaethat bore into the intestinal wall and get into the circulatory system to be transported to muscle • Here the larvae develop into the cysticercusstage (=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

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

34. Phylum Nematoda:The Roundworms

35. 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.

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

37. 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.

38. 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.

39. 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.

40. 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.

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

42. 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.

43. 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.

44. 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.

45. 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.

46. 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.

47. 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.

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

49. Anatomy

50. 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.