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

jawsBony Skeleton

Lungs

Amniotic Egg

Hard Shells

Fur & Milk Glands

Water flow

Collar Cell

Spicule

Pore cell

Pore

Epidermal cell

Archaeocyte

Osculum

Central cavityPores

The Anatomy of a Sponge

What makes the Porifera phyla the most simple of all animals?

What does the name “Porifera” actually mean?

Examples: hydra, coral, sea anemone

Examples: jellyfish, portuguese man of war

Cnidarians have two body forms

Polyp - stationary, vase-shaped

Medusa - swimming, cup-shaped

WORMSPhylum: Annelida

Phylum: PlatyhelminthesPhylum: 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)

http://animal.discovery.com/videos/monsters-inside-me-tapeworm-in-my-brain.html

http://animal.discovery.com/videos/monsters-inside-me-flesh-eating-hookworm.html

http://planetgreen.discovery.com/videos/g-word-red-wigglers.html

http://animal.discovery.com/videos/top-10-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 functions1. 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 asexualreproduction, newlarvae are releasedfrom the snail into the water. They then infect humans, the primary host, by boring through their skin.

Primary host (human)

Intermdiate host(snail)

Humanintestine

Adultfluke

Embryo

Ciliatedlarva

Tailedlarva

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 symmetry Cephalization

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


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

https://www.youtube.com/watch?v=oVuvW5JnYXQ


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


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


2. Circulation/ Respiration/ Excretion- closed circulatory system with vessels; breath through gills or through skin; have excretory organs called nephridia


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

Longitudinalmuscle

Nephridia Ganglia Ringvessels

Reproductiveorgans

Ventralblood vessel

Ganglion

Brain

Mouth

Dorsalblood vessel

CropGizzardBody segments

Setae

The Anatomy of an Earthworm

Anus

Mouth

Brain

Aorticarches

Dorsal blood vessel

Crop (stores)

Gizzard(grinds)

Intestine

Clitellum

Ventral blood vessel

Ventral nerve cord

Esophagus

Pharynx(throat)Segments

Ecology of AnnelidsA. 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

waterC. 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 vesiclessepta

Dorsal blood vessel

crop

gizzard

Intestine

Seminal receptacles

ovaries

esophagus

Ventral nerve cordmetameres

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?

Three Phyla of Worms

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