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WORMS. Flatworms: Phylum Platyhelminthes Soft and Flat Soft and Flat Tissues and Internal Organ Systems Tissues and Internal Organ Systems 3 embryonic.

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Presentation on theme: "WORMS. Flatworms: Phylum Platyhelminthes Soft and Flat Soft and Flat Tissues and Internal Organ Systems Tissues and Internal Organ Systems 3 embryonic."— Presentation transcript:

1 WORMS

2 Flatworms: Phylum Platyhelminthes Soft and Flat Soft and Flat Tissues and Internal Organ Systems Tissues and Internal Organ Systems 3 embryonic germ layers (Ecto, Meso, & Endoderm) 3 embryonic germ layers (Ecto, Meso, & Endoderm) Bilateral symmetry Bilateral symmetry Cephalization Cephalization Acoelomates-without coelom (no fluid- filled body cavity) Acoelomates-without coelom (no fluid- filled body cavity)

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4 Feeding Mouth/anus with pharynx (muscular tube that moves food and waste) Mouth/anus with pharynx (muscular tube that moves food and waste) Gastrovascular cavity – digestion/absorption Gastrovascular cavity – digestion/absorption Parasites – simple or no digestive system b/c feed on blood, tissue fluids, or cell pieces of host Parasites – simple or no digestive system b/c feed on blood, tissue fluids, or cell pieces of host Carnivore Scavenger Parasitic

5 Respiration, Circulation, Excretion Diffusion (transport O 2 and nutrients) through body walls Diffusion (transport O 2 and nutrients) through body walls Flame cells – remove excess water and waste Flame cells – remove excess water and waste Connected to pores in the skin Connected to pores in the skin

6 Response Ganglia – controls N.S. (nerve cell cluster) Ganglia – controls N.S. (nerve cell cluster) Eyespot – detects light changes Eyespot – detects light changes Some have specialized cells to detect chemicals, food, etc. Some have specialized cells to detect chemicals, food, etc.

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8 Movement Cilia on epidermal cells for gliding Cilia on epidermal cells for gliding Muscle cells for twisting/turning Muscle cells for twisting/turning

9 Reproduction Hermaphrodites Hermaphrodites Sexual by 2 worms joining, exchanging sperm, and each lay eggs Sexual by 2 worms joining, exchanging sperm, and each lay eggs Internal fertilization Internal fertilization Asexual by fission (organism splits in 2 and each half grows new parts) Asexual by fission (organism splits in 2 and each half grows new parts)

10 Freshwater flatworms have simple ganglia and nerve cords that run the length of the body. The excretory system consists of a network of tubules connected to flame cells that remove excess water and cell wastes. Most flatworms are hermaphrodites, having male reproductive organs (testes) and female reproductive organs (ovaries) in the same organism. Flatworms use a pharynx to suck food into the gastrovascular cavity. Digested food diffuses from the cavity into other cells of the body. Eyespots in some species detect light. Eyespot Head Gastrovascular cavity Ganglia Nerve cords Excretory system Mouth Pharynx Ovary Testes Excretory tubule Flame cell Figure 27–3 The Anatomy of a Flatworm

11 Classes of Flatworms: Turbellarians Turbellarians Flukes Flukes Tapeworms Tapeworms

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13 Class Turbellaria: Turbellarians Free-living Free-living Marine or fresh water Marine or fresh water Not Parasitic Not Parasitic

14 Ex. Pseudobiceros gloriosus Tropical free-living flatworm (non-parasitic)

15 Ex. Planaria Cross-eyed; fresh water free-living flatworm (non-parasitic)

16 Class Trematoda: Flukes Parasitic Parasitic Infect internal organs of hosts Infect internal organs of hosts Blood flukes – travel to intestines of host Blood flukes – travel to intestines of host Some have Multiple Hosts Some have Multiple Hosts

17 Ex. Blood Fluke (not free-living) Parasite that matures in human blood vessels

18 Schistosoma mansoni (has multiple hosts: Snail=intermediate host Human=primary host)

19 Primary host (human) Intermediate host (snail) Human intestine Adult fluke Embryo Ciliated larva Tailed larva Flukes mature and reproduce sexually in the blood vessels of human intestines. Embryos are released and passed out with feces. Once in the water, embryos develop into swimming larvae that infect an intermediate host (snail). After asexual reproduction, new larvae are released from the snail into the water. They then infect humans, the primary host, by boring through their skin. Figure 27-5

20 Class Cestoda: Tapeworms Parasitic Parasitic Lives in intestines Lives in intestines Long and flat Long and flat Scolex-head with suckers or hooks Scolex-head with suckers or hooks Proglottids-body segments Proglottids-body segments

21 Cow/Fish (intermediate host) consumes food or water w/ zygotes. Hatch to larvae and burrow into muscles as cysts (protected) human eats meat not fully cooked and larvae activated to grow to adult in human intestines.

22 Roundworms: Phylum Nematoda Unsegmented Unsegmented Most are free-living Most are free-living Digestive tract with two openings – mouth and anus Digestive tract with two openings – mouth and anus Pseudocoelom-false body cavity Pseudocoelom-false body cavity

23 Feeding Most are carnivores Most are carnivores Use mouth parts and spines to catch food Use mouth parts and spines to catch food Hook Worms

24 Respiration, Circulation, Excretion Diffusion through body walls Diffusion through body walls

25 Response Simple nervous system Simple nervous system Nerves run body length from Ganglia in head Nerves run body length from Ganglia in head Simple sense organs to detect chemicals from prey or hosts Simple sense organs to detect chemicals from prey or hosts

26 Movement Hydrostatic skeleton Hydrostatic skeleton Muscles and fluid in the pseudocoelom work together to produce movement Muscles and fluid in the pseudocoelom work together to produce movement

27 Reproduction Sexual Sexual Internal fertilization Internal fertilization Separate genders Separate genders

28 Human Disease --Parasitic Roundworms Trichinosis-Causing Worms Trichinosis-Causing Worms Filarial Worms Filarial Worms Ascarid Worms Ascarid Worms Hookworms Hookworms

29 Trichinella Trichinosis Cysts are ingested from eating animal muscle tissue Cysts are ingested from eating animal muscle tissue Females burrow into intestinal wall Females burrow into intestinal wall Larvae travel to organs via bloodstream and form cysts Larvae travel to organs via bloodstream and form cysts

30 Filarial Worms Live in blood and lymph vessels Live in blood and lymph vessels Transmitted by mosquitoes Transmitted by mosquitoes Can block the movement of fluids Can block the movement of fluids Elephantiasis Elephantiasis

31 Ascaris 1. Eggs hatch in intestines 2. Larvae burrow into bloodstream to lungs 3. Travel to air passages, then swallowed 4. Carried to the intestines and mature 5. Eggs released via feces Spread by eating improperly washed vegetables (foods)

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33 Hookworms ¼ of the human population infected with hookworms ¼ of the human population infected with hookworms Eggs hatch outside body and develop in soil Eggs hatch outside body and develop in soil Use sharp toothlike plates and hooks to burrow into skin and enter bloodstream Use sharp toothlike plates and hooks to burrow into skin and enter bloodstream Travel to lungs and then intestines Travel to lungs and then intestines Suck blood causing weakness Suck blood causing weakness Dont walk barefoot outside!!! Dont walk barefoot outside!!!

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35 --Segmented worms with a coelom (body cavity) that is lined with mesoderm Annelids: Phylum Annelida

36 Feeding and digestion Filter feeders to predators Filter feeders to predators Earthworm Earthworm Full Digestive Tract: mouth pharynx esophagus crop gizzard intestine anus Full Digestive Tract: mouth pharynx esophagus crop gizzard intestine anus Crop- store food Crop- store food Gizzard- grind food Gizzard- grind food

37 Circulation Closed system, 2 major blood vessels Closed system, 2 major blood vessels Dorsal blood vessel: tail head (pumps like heart) Dorsal blood vessel: tail head (pumps like heart) Ventral blood vessel: head tail Ventral blood vessel: head tail

38 Respiration and Excretion Respiration- Respiration- Skin (moist due to mucus secretion) - land Skin (moist due to mucus secretion) - land Gills - aquatic Gills - aquatic Excretion- Excretion- Nephridia - filter out fluid/liquid waste Nephridia - filter out fluid/liquid waste Anus – solid waste Anus – solid waste

39 Movement- Movement- Hydrostatic skeleton Hydrostatic skeleton Longitudinal muscles – short and fat Longitudinal muscles – short and fat Circular muscles – long and thin Circular muscles – long and thin Setae- brush hair-like projections Setae- brush hair-like projections Reproduction- Reproduction- Mostly sexual, some hermaphrodites, some separate sexes Mostly sexual, some hermaphrodites, some separate sexes Clitellum-thick band secretes mucus ring after 2 worms exchange sperm for fertilization Clitellum-thick band secretes mucus ring after 2 worms exchange sperm for fertilization Mucus ring slips off and forms protective cocoon hatching Mucus ring slips off and forms protective cocoon hatching

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41 Classes of Annelids

42 Class Oligochaeta: Oligochaetes- Earthworms Few setae on each segment Few setae on each segment Soil or fresh water Soil or fresh water

43 Class Hirudinea: Leeches External parasites External parasites Suck blood and body fluids of host Suck blood and body fluids of host Medicinal Uses Medicinal Uses Reduces swelling and prevents clotting Reduces swelling and prevents clotting

44 Class Polychaeta: Polychaetes Sandworms, bloodworms Sandworms, bloodworms Marine Marine Paired paddle-like appendages w/ setae Paired paddle-like appendages w/ setae Live in coral reefs, sand, mud Live in coral reefs, sand, mud

45 What do you think caused this marking? Worm? Worm? Bacteria? Bacteria? Virus? Virus? Fungus? Fungus? Hickey? Hickey?

46 Ringworm Not caused by a worm! Not caused by a worm! Fungal infection Fungal infection Can occur on any part of body Can occur on any part of body Contact with infected people, animals, soil, etc. Contact with infected people, animals, soil, etc. Medically called Tinea Medically called Tinea

47 Earthworm Dissection

48 External View

49 Internal Structure

50 Pharynx

51 Aortic Arches

52 Seminal Vesicle

53 Seminal Receptacle

54 Septum

55 Crop

56 Gizzard

57 Intestine

58 Ventral Nerve Cord

59 Dorsal Blood Vessel


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