Phylum Platyhelminthes The Worms Phylum Platyhelminthes Phylum Nematoda Phylum Annelida

The Worm Characteristics Bilateral symmetry – the simplest organisms to exhibit this type of symmetry Invertebrates Hydrostatic pressure provides structural support

Phylum Platyhelminthes - Flatworms Classes: Class Cestoda - Tapeworms Class Turbellaria - Planeria Class Trematoda – Flukes

Phylum Platyhelminthes - Flatworms Examples: Tapeworms Planeria Parasitic Flukes

Phylum Platyhelminthes - Flatworms Body Structure: Flattened Lack segmentation Acoelomate – no body cavity ˂1 mm to many meters long Definite head region and body organs Live in aquatic areas, other organisms

Phylum Platyhelminthes - Flatworms Digestion: Mouth, Pharynx, digestive tract (no anus) Incomplete digestive tract Feed on algae, dead organisms, blood, etc.

Phylum Platyhelminthes - Flatworms Nervous System: Central nervous system (simplest organism to possess one) – cluster of nerve cells (ganglion) and two nerve cords Light sensitive eyespots

Phylum Platyhelminthes - Flatworms Locomotion: Contracting longitudinal muscles Cilia on underside Mucous lubricates organism to allow it to glide

Phylum Platyhelminthes - Flatworms Other Organ Systems: Contains no true organs No respiratory system No excretory system Absorption of oxygen occurs through diffusion

Phylum Platyhelminthes - Flatworms Sexual Reproduction: Almost always hermaphroditic Flatworms exchange sperm to fertilize eggs internally Zygotes are released, attached to weeds, and develop in tiny cocoon Hatch in 2-3 weeks

Phylum Platyhelminthes - Flatworms Asexual Reproduction: Fragmentation (Fission) Regeneration Can attach to rough substrate and stretch its body into two pieces Can be cut into and regenerate Can self-fertilize

Phylum Platyhelminthes - Flatworms Ecological Role: Food source for dragonflies, water bugs, crustaceans, etc. Can be parasitic and have oral suckers or hooks to allow them to attach to a host Symptoms include: headache, fever, joint pain, chronic illness, swelling, tissue damage, etc. Cleanliness, Good hygiene, eating uncontaminated foods

Phylum Nematoda - Roundworms Classes: Class Enoplea – Trichina, Whipworm Class Chromadorea (used to be known as Secernentea) - Hookworm, Ascaris, Pinworm, Heartworm

Phylum Nematoda - Roundworms Examples: Hookworms Ascaris Pinworm Filarial worms (Heartworms)

Phylum Nematoda - Roundworms Body Structure: Rounded Lack segmentation Psuedocoelomate – false cavity No circular muscles Longitudinal muscles only (lengthwise down body) Aquatic environments and other organisms

Phylum Nematoda - Roundworms Digestion: Complete digestive tract – mouth and anus are located in different locations Mouth, pharynx (throat), Long gut cavity, no contracting muscles, and an anus Feed on dead organisms (plants and animals) and the organism in which they live

Phylum Nematoda - Roundworms Nervous System: Two nerves (dorsal and ventral) Branch toward ganglia (the brain)

Phylum Nematoda - Roundworms Locomotion: Thrash to allow contractions Hydrostatic skeleton uses water for movement

Phylum Nematoda - Roundworms Other Organ Systems: No respiratory system – breathe through diffusion No circulatory system Excretory tubes that transfer waste to anus

Phylum Nematoda - Roundworms Sexual Reproduction: Females produce eggs Males produce sperm Internal fertilization Eggs are laid Some hatch outside Some hatch in host

Phylum Nematoda - Roundworms Ecological Roles: Important to decomposition and soil nutrition Feed on bacteria, fungi, protozoans and even other nematodes Important for nutrient cycling and release of nutrients for plant growth. Some attack insects, and help to control insect pests. Some nematodes are reared commercially and released for the control of certain insect pests as a biological insecticide.

Phylum Nematoda - Ascaris Ecological Roles: Parasitic intestinal worm Common infection in horses, humans, and pigs Symptoms: fever, coughing, wheezing, severe abdominal cramps, nausea, and vomiting

Phylum Nematoda - Hookworm Ecological Roles: Curved head that resembles a hook Hook to intestines Causes anemia in patient Found in soil, burrow through skin, most commonly foot

Phylum Nematoda - Pinworm Ecological Roles: Most common parasite in the United States Lives in large intestine Symptoms: extreme itching, worms in stool (fecal material), pain around rectal area Easily spread and highly contagious through contact

Phylum Nematoda - Trichina Ecological Roles: Contracted by eating infected meat Juveniles enter blood vessels and lymph nodes and are carried to muscles Symptoms: fever, swelling of face and eyes, and serious muscle pain Neck, chest, and limbs can swell if treatment is not sought

Phylum Nematoda - Whipworm Ecological Roles: Common in U.S. in humans Intestinal infection Occurs through contaminated food or unhygienic habits Symptoms: bloody diarrhea, abdominal pain, anemia, nausea, dehydration, etc.

Phylum Nematoda – Filarial Worms Ecological Roles: At least 8 species that infect humans Includes Elephantiasis, river blindness, dog heartworm Worms live in the lymphatic system Carried by mosquitoes

Phylum Nematoda – Filarial Worms Elephantiasis: Fever Pain in testicles Enlarged lymph nodes in groin Massively swollen legs, genitalia, breasts Swollen liver or spleen

Phylum Annelida – Segmented Worms Examples: Class Oligochaeta - Earthworm Class Hirudinea - Leeches Class Polychaetes - Bristle Worms

Phylum Annelida – Segmented Worms Examples: Earthworm Leeches Bristle Worms

Phylum Annelida – Segmented Worms Body Structure: Body divided into ring- like segments Coelomate (has a true body cavity) Look like a stack of donuts Have circular muscles Have longitudinal muscles

Phylum Annelida – Segmented Worms Body Structure: Some (Polychaetes) have external, paddle-shaped structures (parapodia) with chaetae or bristles - external gills or appendages

Phylum Annelida – Segmented Worms Digestion: Complete digestive tract – mouth and anus located at different locations Mouth, Pharynx, Esophagus, Crop. Gizzard, Intestine, and Anus

Phylum Annelida – Segmented Worms Circulatory System: Closed circulatory system (10 aortic arches) Oxygen is pumped throughout the body through the blood vessels

Phylum Annelida – Segmented Worms Respiration and Excretion: Breathe through their skin Some have gills Nephridia (kidneys) found in every segment to get rid of waste

Phylum Annelida – Segmented Worms Nervous System: Has two structures that form the brain ganglia The ventral and dorsal nerves extend down the body Photoreceptors that detect light Detect vibrations easily

Phylum Annelida – Segmented Worms Locomotion: Muscle contractions allow for movement (both circular and longitudinal) Setae are hairlike structures that push into the soil for anchoring during movement

Phylum Annelida – Segmented Worms Sexual Reproduction: Some are hermaphroditic Can receive sperm from other worms via the clitella The clitella produces a cocoon from which fertilized eggs hatch

Phylum Annelida – Segmented Worms Asexual Reproduction: Regeneration/Fragmentation allows for the earthworm to regenerate the missing part

Phylum Annelida – Segmented Worms Ecological Role: Food source for organisms such as dragonflies, water bugs, crustaceans, etc. Parasitic symptoms: headache, fever, joint pain Stimulates circulation; saliva acts as anesthetic; reduce swelling and clotting