Zoology Section 2

Needs of animals

Flatworms and round worms

Parasites

Activities for this section

• Read 647-653 flat worms and round worms Nematoda

• Read Old Biology Book about Platyhelminthes Chap 30

• Work on worksheets in binder (4 sides)

• Data Lab pg 652

• Parasite WEB QUEST

• PARASITE WEB QUEST • Log on to any computer in the school• click on My Computer• click on projects on 'tvhs-ad1.tvschools.net' (P:)• click on Taylor-Lehman• click on Zoology• click on webquest.html• follow the links• QUESTIONS• Answer the following questions for each of the five

cases presented in the Computer Lab activity. Write complete answers.

• 1. What is the scientific name of the parasite? (Use the proper format)

• 2. Hypothesize about the method of infection.• 3. How will you treat each client’s disease.

GREATEST CONCERNS OF ANIMALS• 1.________________________• Solutions

– A. _______________________________– B. be filled with water and limit evaporation (ex. Skin, shell,

cuticle)• 2. ____________________• Solutions

– A. ______________________________– B. stay moist (oxygen in the air can be absorbed through the

skin)– C. have a system to bring oxygen in and distribute it (ex. Gills,

lungs)• 3. _______________________• Solutions

– A. Bring food inside the body to the gut for digestion and …• a. have all the cells close to the gut• B. have a system to distribute the digested food (ex. Blood stream)

GREATEST CONCERNS OF ANIMALS• 1.___WATER (remember the importance of water?) ___• Solutions

– A. ______________________– B. be filled with water and limit evaporation (ex. Skin, shell,

cuticle)• 2. ____________________• Solutions

– A. _________– B. stay moist (oxygen in the air can be absorbed through the

skin)– C. have a system to bring oxygen in and distribute it (ex. Gills,

lungs)• 3. _______________________• Solutions

– A. Bring food inside the body to the gut for digestion and …• a. have all the cells close to the gut• B. have a system to distribute the digested food (ex. Blood stream)

GREATEST CONCERNS OF ANIMALS• 1.___WATER (remember the importance of water?) ___• Solutions

– A. _____stay in the water_________________– B. be filled with water and limit evaporation (ex. Skin, shell,

cuticle)• 2. ____________________• Solutions

– A. _________– B. stay moist (oxygen in the air can be absorbed through the

skin)– C. have a system to bring oxygen in and distribute it (ex. Gills,

lungs)• 3. _______________________• Solutions

– A. Bring food inside the body to the gut for digestion and …• a. have all the cells close to the gut• B. have a system to distribute the digested food (ex. Blood stream)

GREATEST CONCERNS OF ANIMALS• 1.___WATER (remember the importance of water?) ___• Solutions

– A. _____stay in the water_________________– B. be filled with water and limit evaporation (ex. Skin, shell,

cuticle)• 2. _____OXYGEN_______________• Solutions

– A. _________– B. stay moist (oxygen in the air can be absorbed through the

skin)– C. have a system to bring oxygen in and distribute it (ex. Gills,

lungs)• 3. _______________________• Solutions

– A. Bring food inside the body to the gut for digestion and …• a. have all the cells close to the gut• B. have a system to distribute the digested food (ex. Blood stream)

GREATEST CONCERNS OF ANIMALS• 1.___WATER (remember the importance of water?) ___• Solutions

– A. _____stay in the water_________________– B. be filled with water and limit evaporation (ex. Skin, shell,

cuticle)• 2. _____OXYGEN_______________• Solutions

– A. __stay in the water (oxygen dissolves in water) _______– B. stay moist (oxygen in the air can be absorbed through the

skin)– C. have a system to bring oxygen in and distribute it (ex. Gills,

lungs)• 3. _______________________• Solutions

– A. Bring food inside the body to the gut for digestion and …• a. have all the cells close to the gut• B. have a system to distribute the digested food (ex. Blood stream)

GREATEST CONCERNS OF ANIMALS• 1.___WATER (remember the importance of water?) ___• Solutions

– A. _____stay in the water_________________– B. be filled with water and limit evaporation (ex. Skin, shell,

cuticle)• 2. _____OXYGEN_______________• Solutions

– A. __stay in the water (oxygen dissolves in water) _______– B. stay moist (oxygen in the air can be absorbed through the

skin)– C. have a system to bring oxygen in and distribute it (ex. Gills,

lungs)• 3. ______FOOD_________________• Solutions

– A. Bring food inside the body to the gut for digestion and …• a. have all the cells close to the gut• B. have a system to distribute the digested food (ex. Blood stream)

ANIMAL PHYLA (INVERTEBRATES)

• I. PORIFERA –sponges• II. CNIDARIA- jellyfish ,coral

III. phylum PLATYHELMINTHES – “flat worms”

• examples fluke, planaria, tapeworm

• Examine specimens being passed around the room

III. PLATYHELMINTHES – characteristics

• Bilateral symmetry• Aquatic or semi aquatic• 3 cell layers (see lab)• nervous tissue concentrated at anterior end • regeneration• hermaphrodites- contain both ovaries and

testies• asexual reproduction by fragmentation• every cell is near the surface of the body

(gas exchange)

Some cool marine flatworms

• Although very thin and delicate, flatworms are active carnivores and scavengers, using their proboscis to feed on dead or injured animals and colonial animals such as bryozoans and soft-corals. The worms can quickly glide along the bottom by using the fine hair like cilia which cover their body. When disturbed they can swim for a considerable period of time by throwing the sides of their body into undulating waves.

1. Class Turbellaria- planaria• Free living in fresh water• See handout

– Digestion- Nutrients absorbed by intestinal wall and waste goes out through mouth

• Muscular pharynx comes out of central mouth to feed

- Nervous system: Brain, two nerve cords, and light-sensitive eye spots

– Water balance- Water continually enters by osmosis

Add to your notes

NAME HOSTS INFECTION SITE SYMPTOMSMETHOD OF

PREVENTION

    IN HUMANS    

HOOKWORM        

         

ASCARIS        

         

TRICHINIA        

         

ELEPHANTIASIS WORM        

         

         

         

TAPEWORM        

         

FLUKE "SCHISTOSOMA"        

         

         

         

2. Class Trematoda- flukes, “schistosomiasis”• See handout about this

parasite on humans and snails

3. Class Cestoda- tapeworms

• Not as much division of labor as in the free living organism

• No mouth nor digestive system

• Absorbs nutrients directly from host’s intestines

• Highly specialized for reproduction

still the phylum Platyhelminthes

• Class Cestoda- Parasitic flatworms (tapeworms)– Suckers and hooks attach to

walls of intestines– Food absorbed from host’s

intestines directly through the tapeworm’s skin

– Grow by producing a string of rectangular body sections (proglottidsproglottids)

• Each proglottid is a reproductive unit

• Added continually through life

• May grow up to 12 m (40 ft.) long

• Most occur in vertebrates• Dozen types in humans• Taenia saginata- Beef

tapeworm– Live in cow muscles in

cysts– High temp. kills larvae

TAPEWORM LIFE CYCLE

• cow eats grass contaminated with eggs• embryo digs through intestines to blood stream• larva develop and burrow into muscle• cysts develop in muscle• human eats insufficiently cooked meat• cyst develops and attaches to intestine wall• robs nutrients• eggs released in feces

SCOLEX

EGGS RELEASED FROM PROGLOTTIDS

TAPEWORM ATTACHED TO INTESTINAL WALL

CYSTS IN MUSCLE OF COW

SCOLEX

Cow consumes eggs

Human consumes cysts

Brand new phylum

IV. Phylum NEMATODA- “round worms”

• Examples Ascaris, Trichinella, hookworms

• Complete digestive system –mouth to anus

• Free-living

• Parasites on plants, animals and man (50)

• 1. HOOKWORM life cycle• Hookworms are found in tropical and semitropical regions. • Their larva develop in the soil. Entrance of the larva to the human

body is through the skin, especially the skin of the feet. • Once through the skin the larva enters the person’s blood vessels,

traveling through the heart to the lungs. • Leaving the lungs, the larva migrates through the windpipe and

arrive in the person’s throat.• Being swallowed by their host, the larva enters the stomach and

continue on, using their jaws to attach themselves to the host’s intestinal walls.

• The larvae, sucking blood from their host’s intestinal walls, grow into adult worms.

• A victim usually develops anemia and lowered vitality as a result of blood loss.

• Adult worms mate and reproduce in the host’s intestines. A great number of eggs are laid by the female and leave the body with the feces.

• Eggs that are deposited in warm soil develop into larvae and the cycle is ready to be repeated.

Blood

Heart

Lungs

Windpipe

Intestines

• 2. TRICHINA WORM• The Trichina worm is a parasitic roundworm, which enters a

human’s body in the form of dormant larva cysts, imbedded in the muscle of a pig.

• Trichina larva form dormant cysts in the muscles of pigs, also in dogs, cats and rats.

• When a person eats a piece of insufficiently cooked pork containing one or more of the live cysts, it is very possible that the person’s digestive system enzymes will dissolve the cysts in the intestines, freeing the larva.

•• The larva in the intestine then grow to mature trichinae worms and

produce a new generation of larvae.•• The new larvae penetrate into the blood and lymph vessels and

travel to various body muscles where they form new cysts that can become a very painful disease (TRICHINOSIS). They are difficult to combat or remove because of their microscopic size.

• These cysts eventually die or in cases where an infected animal is eaten by another anima, the cycle is renewed .

• VARIOUS RELIGIOUS GROUPS HAVE PROHIBITIONS ON EATING PORK

• 3. ASCARIS WORM• The Ascaris is a non-segmented parasitic round worm.• Eggs of the ascaris worms are found in contaminated

foods, such as pork, beef, fish, and vegetables. Untreated water may also be contaminated.

• When contaminated food, improperly cooked, is eaten by humans or other animals, the eggs, upon reaching the intestines will hatch into larvae.

• The larva bore through the host’s intestinal walls, enter the blood stream and travel to the lungs, through the windpipe and down the host’s throat.

• Being swallowed by the host, the larvae again reach the small intestines. This entire journey has taken about 10 days.

• Remaining in the host’s intestine (about 2 months) the larvae grow to maturity. The female worms lay many fertilized eggs (about 20,000 a day) The eggs pass out of the host’s body along with the feces, which, when coming in contact with food, eaten by another susceptible animal, starts the cycle again.

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NAME HOSTSINFECTION

SITE SYMPTOMS METHOD OF

    IN HUMANS  PREVENTIO

N

HOOKWORM

eggs in the soil

small intestines enters

anemia, vomiting wear shoes

   via the skin or

ingestionconstipation

diarrhea

defecate in latrines

ASCARIS eggs in water enter by mouth to

peritonitis, enlarged liver

keep sewage water away

   small intestines and

lungsdand spleen,

pneumoniafrom drinking and

irrigation

TRICHINIA

rats, pigs and humans hatch in stomach to fever and pain

cook meat completely

 

cysts in muscle

intestines and into muscles    

ELEPHANTIASIS WORM

mosquitos transmits

obstruction of lymphatic

thickening of skin kill mosquitos

  filarial worm system    

TAPEWORM

food infected with eggs digestive tract

malnutrition, diarrhea wash or cook food

     abdominal

discomfort  

FLUKE"SCHISTOSOMA"   penetrates skin and

fever, fatigue, cough kill snails

  snailMigrates to lungs

and liverabdominal pain,

diarrheaavoid water with

snails

         

         

Practice problems

Practice problems

Practice problems

Practice problems

Topics• Name phyla and classes

• Provide examples of above

• Contrast features of the 2 phyla

• Lists sources of parasites

• List methods of prevention

• Describe life cycle of hookworm, fluke and tapeworm

• List adaptations for parasitic life style

• Study worksheets

• Anatomy of a planaria and tapeworm