Three Phyla of Worms

Review the Animal Kingdom  4 Major Characteristics?  Multicellular  Eukaryotic  Heterotrophs  Cells lack cell walls

7 Essential Functions?  Feeding  Respiration  Circulation  Excretion  Response  Movement  Reproduction

Brain Encased Skull jaws Bony Skeleton Lungs Amniotic Egg Hard Shells Fur & Milk Glands

Water flow Collar Cell Spicule Pore cell Pore Epidermal cell Archaeocyte Osculum Central cavity Pores The Anatomy of a Sponge

Ecology of Sponges 1. Ideal habitats for marine animals such as snails, sea stars, sea cucumbers, and shrimp 2. Mutually beneficial relationships with bacteria, algae and plant-like protists

Examples: hydra, coral, sea anemone Examples: jellyfish, portuguese man of war Cnidarians have two body forms Polyp - stationary, vase-shaped Medusa - swimming, cup-shaped

Ecology of Cnidarians  A. Source of new drugs/chemicals  sunscreen 855  B. Provide habitats for marine organisms  C. Source of food for other organisms (like sea turtles)  D. Symbiotic relationships with other organisms

WORMS Phylum: Annelida Phylum: Platyhelminthes Phylum: Nematoda

What’s a Worm???  A long, thin invertebrate with BILATERAL symmetry, a nervous system, and cephalization  Simplest animal to have a true organs like a brain!  Reproduction - Sexual (hermaphroditic – male and female reproductive organs) and Asexual – Fission (breaking into pieces)  Many are parasites- (good/bad relationship) live on or in a host

3 Distinct Phyla  Platyhelminthes (flatworms)  Nematoda (roundworms)  Annelida (segmented worms)

 inside-me-tapeworm-in-my-brain.html inside-me-tapeworm-in-my-brain.html  inside-me-flesh-eating-hookworm.html inside-me-flesh-eating-hookworm.html  word-red-wigglers.html word-red-wigglers.html  bloodsuckers-leech.html bloodsuckers-leech.html

Characteristics of Flatworms (Platyhelminthes) A. Soft flattened worms with true tissues and internal organs. B. Simplest animals to have bilateral symmetry and cephalization.

Flatworms carry out 7 essential functions 1. Feeding – some carnivorous, most parasitic; one opening into gut; pharynx sucks in food and releases waste 2. Respiration/ Circulation/ Excretion – No respiratory No circulatory system, system; Obtain nutrients and oxygen by diffusion directly into cells. Simple excretory system of specialized cells.

3. Response/Movement – ganglia= groups of nerves in head control nervous system (like a brain); “ladder” of nerves run over body; eyespot detects light; move by cilia and squirming using outer layer of muscle tissue

Diseases caused by parasitic flatworms A. Flukes-Usually infect internal organs of host – Example: The blood fluke Schistosoma- causes tissue damage that could result in death

Section 27-1 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. Primary host (human) Intermdiate host (snail) Human intestine Adult fluke Embryo Ciliated larva Tailed larva Schistosome Life Cycle Primary host Secondary host 4. Inside the human host, the flukes produce eggs that clog blood vessels, causing swelling and damage to lungs, liver, spleen, and/or intestines

Diseases caused by parasitic flatworms A. Flukes-Usually infect internal organs of host – Example: The blood fluke Schistosoma B. Tapeworms – Long, flat, and have adaptations for life inside intestines of host

Parasitic Flatworms Head with a scolex - suckers and hooks which attach to the host’s intestinal lining

Check Your Understanding  What type of symmetry do all worms have?  Worms are the simplest animals to have ____________ and ______________.  How do flatworms obtain nutrients and oxygen? Bilateral symmetryCephalization Bilateral Diffusion

The Characteristics of Roundworms Phylum Nematoda A. Body plan- First animals to have a one way digestive system with mouth and anus (tube within in a tube); B. First animals to have a fluid filled body cavity called a pseudocoelom- “false body cavity”

Roundworms Carry Out 7 Essential Functions 1. Feeding- many are carnivores with grasping mouthparts, some herbivores, many are parasites 2. Respiration/Circulation/ Excretion- No Respiratory or Circulatory Systems; rely on diffusion. Simple excretory organs.

3. Response/movement -have ganglia (“brain”)and simple nervous system, have muscular system and move like snakes

Diseases caused by parasitic roundworms A. Trichinella causes painful cysts in the muscle tissue of humans and other animals- transmitted by eating undercooked meat containing worm eggs

Diseases caused by parasitic roundworms B. Filarial worms cause Elephantiasis- fluid buildup that causes abnormally large limbs – transmitted through the bite of insects like mosquitos

Diseases caused by parasitic roundworms C. Ascarids cause malnutrition in humans, horses, cows, etc by filling the intestinal tract of its host and absorbing all nutrients

Diseases caused by parasitic roundworms D. Hookworms attach to the lungs and intestines and suck blood – common in humans(1/4 of world population); larvae pierce the skin & burrow into the body. Can severely damage internal organs. Transmitted through humans’ and other animals’ waste. (Wear Shoes!)

Check Your Understanding  What is different about the roundworm’s digestive system as compared to the flatworm’s digestive system?  How are roundworm diseases transmitted?  What are ganglia? A roundworm has a mouth and anus. A flatworm only has one opening By eating undercooked meat, walking barefoot, insect bites Nerve tissue that function as simple brains

Phylum Annelida

anus mouth clitellum Figure 1 – Body Structure

Phylum Annelida A. Body Plan- tube within a tube, digestive system with mouth and anus; body divided into sections called septa that are specialized for different functions. First animals to have true circulatory system and coelom – body cavity.

Annelids carry out 7 essential functions? 1. Feeding- predators to filter feeders; use pharynx to get food, stored in crop, ground up in gizzard, absorbed in intestine.

 Mouth  pharynx  esophagus (throat)  crop (storage area)  gizzard (grinds food)  intestines (digestion)  anus One-way Digestive System

Annelids carry out 7 essential functions? 2. Circulation/ Respiration/ Excretion- closed circulatory system with vessels; breath through gills or through skin; have excretory organs called nephridia

Annelids carry out 7 essential functions? 2. Circulation/ Respiration/ Excretion- closed circulatory system with vessels; breath through gills or through skin; have excretory organs called nephridia 3. Response/Movement- have ganglia in each segment and in the head, nervous system; move by contracting and relaxing muscles

Section 27-3 Anus Clitellum Circular muscle Longitudinal muscle Nephridia Ganglia Ring vessels Reproductive organs Ventral blood vessel Ganglion Brain Mouth Dorsal blood vessel Crop Gizzard Body segments Setae The Anatomy of an Earthworm

Anus Mouth Brain Aortic arches Dorsal blood vessel Crop (stores) Gizzard (grinds) Intestine Clitellum Ventral blood vessel Ventral nerve cord Esophagus Pharynx (throat) Segments

Ecology of Annelids A. Aerate, mix, and fertilize the soil- have created some of the most fertile soils on earth! B. Tunnels provide passage ways for plant roots and water C. Important in the diets of many other animals such as birds, toads and snakes; marine annelids important in the diets of fishes, crabs, and lobsters

Check Your Understanding  Name one characteristic all three worm phyla have in common  What type of circulatory system do segmented worms have?

Figure 2 – Reproductive Structures Clitellum Sperm Grooves Male genital pores setae prostomium Earthworm coccoons

mouth brain pharynx Aortic arches Seminal vesicles septa Dorsal blood vessel crop gizzard Intestine Seminal receptacles ovaries esophagus Ventral nerve cord metameres Ventral blood vessel nephridia

Review  What are the three types of worms?  How do worms such as a planarian “see”?  What kind of worm includes leeches and marine worms?  What makes a segmented worm, such as an earthworm, different from other worms in regards to their circulatory system?