Tuesday, February 27, 2007

Lab Photo

I cannot add images.
(Cannot upload pictures from my folder.)
Lab samples are at the back of Mr. Haji's classroom.

Monday, February 26, 2007


"Animal Flatworm". MCWDN.

C. Massengale. "Biology class notes". HRW.

"Platyhelminthes". Wikipedia. 2007.

Rudman, W.B. "Flatworm". Seaslugforum. 1998-2007.

Miller, Kenneth R. and Joseph Levine. Biology. 4th ed. Upper Sadle River, NJ: Prentice Hall, 1998.

Test yourself!

Some of questions may be difficult, but try your best.

1. Which of the following combinations of organisms contains only radially symmetrical animals?
A. Jellyfish, sponges, and roundworms.
B. Roundworms, hydra, and sea anemones.
C. Sponges, jellyfish, and Portuguese men-o-war.
D. Portuguese men-o-war, roundworms, and flukes.

2. Cephalization MOST ACCURATELY refers to the development of
A. a brain.
B. a head.
C. a scolex.
D. an anterior end.

3. What system do flame cells and nephridiopores belong to?
A. Excretory system of planaria.
B. Circulatory system of planaria.
C. Excretory system of roundworms.
D. Circulatory system of roundworms.

4. What is the advantage to a parasitic worm of having multiple hosts during its life cycle?
A. Finding a mate.
B. Distributing their young.
C. Infecting a wider range of animals.
D. Sampling a wider range of nutrient sources.

5. A parasitic worm that has a dormant stage in a mammal can usually be found in a
A. cyst.
B. snail.
C. scolex.
D. proglottid.

6. A human with a tapeworm most likely got it by consuming
A. raw snails.
B. unsanitary water.
C. poorly cooked meat.
D. unwashed leafy vegetables.

7. If a pin were poked into a nematode from the outside into the intestine, what would it pass through?
A. Ectoderm, mesoderm, pseudocoelom, then endoderm.
B. Ectoderm, pseudocoelom, mesoderm, then endoderm.
C. Ectoderm, mesoderm, pseudocoelom, mesoderm, then endoderm.
D. Ectoderm, mesoderm, endoderm, pseudocoelom, mesoderm, then endoderm.

8. Which of the following best describes the movement of a nematode?
A. Crawling.
B. Swimming.
C. Ciliated gliding.
D. Whipping back and forth.

9. The development of a coelom is coupled with the earliest specialization of a/an
A. nervous system.
B. excretory system.
C. circulatory system.
D. respiratory system.

10. Flatworms are the most complicated and complex of the worm groups.
A. True
B. False

11. A living thing that lives off another living thing called a host is
A. Symbiotic
B. Parasitic
C. Bilateral

12. A flatworm reproduces by
A. Splitting in half
B. Budding
C. Sexually

13. The flatworm has
A. One complex brain
B. Two simple brains
C. No brain

14. A flatworm has one opening to take in food and get rid of wastes.
A. True
B. False

15. A tapeworm has
A. Asymmetry
B. Bilateral Symmetry
C. Radial Symmetry

Answer: 1.C 2.A 3.A 4.B 5.A 6.D 7.A 8.D 9.C 10.B 11.B 12.A 13.B 14.A 15.B


Most roundworms and flatworms are found in all parts of the Earth such as in soil, salt flats, and aquatic sediments.

Adaptation to their environment
Unlike sponges or cnidarians, unsegmented worms have well-developed senses and nerve systems to live inside a host. Unsegmented worms also have specialized cells such as muscles cells which help worms to contract and twist their bodies. However, some of unsegmented worms are parasitic and may cause terrible damages and diseases to living organism.

Comparisons to other phyla
Phylum porifera, also known as sponge, does not have well-developed nerve systems, and gastro vascular cavity. Unlike sponges and cnidarians, unsegmented worms are mostly parasitic and have structure that help them to absorb food and harm their hosts.

All highlighted words are important to know and defined in the paragraphs.

Interesting Facts

Unsegmented worms are generally parasitic rather than the free-living members of their phylum. Parasitic round worms include hookworms, trichinosis-causing worms, filarial worms, and eye worms.

-Hookworms are serious human intestinal parasites that are found in southern United States and cause weakness and poor growth to its host.

-Trichinosis is a disease caused by the roundworm Trichinella. These roundworms damage muscle cells and other organs that cause terrible pain for the host.

-Filarial worms are threadlike worms that live in the blood and lymph vessels of birds and mammals. Filarial worms block the passage of fluids within the lymph vessels and cause elephantiasis, a condition in which an affected part of the body sells enormously.

-Eye worms affect both human and baboons. The worms got its name because they often move across the surface of the eye.

EXTRA (Phylum Rotifera)

Phyum Rotifera

- Type of unsegmented worms
- Known as rotifers or wheel animals
- Free-swimming animals
- Have a ring of cilia around the mouth
- Simple nervous system (nerve cords, ganglia)
- Light sensitive eye spots


phylum Platyhelminthes
Class Trubellaria

- Free-living flatworms
- Less than 1 centimeter in length
- Found in moist tropical areas
- Freshwater planarian (Dudesia)

Class Trematoda
- Also known as flukes
- Some are external parasitic flatworms that live on the skin, mouth, gills of a host
- Many are internal parasites that infect the blood and organs of humans.
- Although flukes are small, they can damage their host greatly during their life cycle.
*Blood flukes, genus Schistosoma, live within the blood vessels of the intestines that are parasitic to hosts. Most flukes are hermaphrodites and undergo sexual reproduction. Flukes produce more than 10,000 eggs and fluke eggs are not digested by the host and become part of the feces. Eggs are hatched as they get into the water. Soon the larvae burrow inside specific snails where the flukes are reproduced asexually.

* People who are infected by fluke often get sick and die as their immune systems are weakened by fluke. “Swimmers itch” is also caused by flukes living in freshwater. However, because the worms do not detect humans as their hosts, the itch goes away after a time and the bodies repair the damages.

Class Cestoda
- long, flat parasitic worms
- Also know as tapeworm
* These members have a head called a scolex on which a ring of hooks are attached. The structure help worms to attach to intestine where worms absorb food that is already digested by their hosts.

* Proglottids or sections are formed behind the scolex of the tapeworm. Proglottids make up the body of the tapeworm. Proglottids are located at the anterior region of the young tape worms, and mature tapeworms have proglottids at the posterior region of the tapeworms.
* If food or water that is contaminated with tapeworm eggs is eaten by cows, pigs, or other hosts, the eggs enter the bodies of hosts and hatch into larvae. These larvae burrow into the muscle tissue of the host and form a dormant protective stage called cysts. Once the larvae become active, it absorbs food, hanging on the intestinal wall.

phylum Nematoda
- Parasitic roundworm lives in human bodies
- Known as ascarid
Ascarids live in the intestines, where they produce hundreds of eggs. The eggs eventually leave the body in the feces. Eggs hatch into larvae when they enter other hosts’ intestines. The young worms burrow into the walls of the intestines and enter blood vessels. They travel to the lungs and climb up into the throat where they are swallowed. Worms are carried back into the intestines again and repeat the cycle.