I cannot add images.
(Cannot upload pictures from my folder.)
Sorry.
Lab samples are at the back of Mr. Haji's classroom.
Tuesday, February 27, 2007
Monday, February 26, 2007
Reference
"Animal Flatworm". MCWDN.
<http://www.mcwdn.org/Animals/Flatworm.html>.
C. Massengale. "Biology class notes". HRW.
http://sps.k12.ar.us/massengale/unsegmented_worm_notes_b1.htm
"Platyhelminthes". Wikipedia. 2007.
<http://en.wikipedia.org/wiki/Platyhelminthes>.
Rudman, W.B. "Flatworm". Seaslugforum. 1998-2007.
<http://www.seaslugforum.net/factsheet.cfm?base=flatworm>.
Miller, Kenneth R. and Joseph Levine. Biology. 4th ed. Upper Sadle River, NJ: Prentice Hall, 1998.
<http://www.mcwdn.org/Animals/Flatworm.html>.
C. Massengale. "Biology class notes". HRW.
http://sps.k12.ar.us/massengale/unsegmented_worm_notes_b1.htm
"Platyhelminthes". Wikipedia. 2007.
<http://en.wikipedia.org/wiki/Platyhelminthes>.
Rudman, W.B. "Flatworm". Seaslugforum. 1998-2007.
<http://www.seaslugforum.net/factsheet.cfm?base=flatworm>.
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
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
Adaptation/Habitat
Habitat
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.
Vocabulary
All highlighted words are important to know and defined in the paragraphs.
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.
Vocabulary
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.
-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)
Examples
phylum Platyhelminthes
Class Trubellaria
- Free-living flatworms
- Less than 1 centimeter in length
- Found in moist tropical areas
- Freshwater planarian (Dudesia)
Cla
ss Cestoda
- long, flat parasitic worms
- Also know as tapeworm
Class Trubellaria
- Free-living flatworms
- Less than 1 centimeter in length
- Found in moist tropical areas
- Freshwater planarian (Dudesia)
Class Trem
atoda
- 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.
atoda- 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.
Cla
ss 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
Ascaris
- 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.
Ascaris
- 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.
Response
phylum Platyhelminthes
Nervous systems of free-living flatworms allow them to gather information from their environment. Free-living flatworms have well-developed nervous system than cnidarians and sponges. Flatworms are capable of simple learning and can sense taste, smell, touch, and light. Free-living flatworms have a brain, a control center of a simple nervous
system, located in the anterior end. Long nerve cords stretches throughout the body from the anterior end to posterior end. Many flatworms have light sensitive organs called ocelli, or eyespots. Flatworms also have cells that are sensitive to chemicals found in food, and other cells that tell the worm which way the water around them is flowing.
Parasitic flatworms do not have much of nervous systems because they live in their host and absorb food from intestinal walls.
★The eyespots do not help flatworms to see objects; however, they detect whether the animal is in light or in darkness.
phylum Nematoda
Roundworms have simple nervous systems. They contain ganglia, or groups of nerve cells, in the head region. Roundworms have sensitive organs that detect chemicals given off by hosts. Nerves stretch from the ganglia at the head region to the posterior part of the body. These nerves transmit sensory information and control movement.
Nervous systems of free-living flatworms allow them to gather information from their environment. Free-living flatworms have well-developed nervous system than cnidarians and sponges. Flatworms are capable of simple learning and can sense taste, smell, touch, and light. Free-living flatworms have a brain, a control center of a simple nervous
system, located in the anterior end. Long nerve cords stretches throughout the body from the anterior end to posterior end. Many flatworms have light sensitive organs called ocelli, or eyespots. Flatworms also have cells that are sensitive to chemicals found in food, and other cells that tell the worm which way the water around them is flowing.Parasitic flatworms do not have much of nervous systems because they live in their host and absorb food from intestinal walls.
★The eyespots do not help flatworms to see objects; however, they detect whether the animal is in light or in darkness.
phylum Nematoda
Roundworms have simple nervous systems. They contain ganglia, or groups of nerve cells, in the head region. Roundworms have sensitive organs that detect chemicals given off by hosts. Nerves stretch from the ganglia at the head region to the posterior part of the body. These nerves transmit sensory information and control movement.
Reproduction
phylum PlatyhelminthesMost flatworms are hermaphrodites, which mean that they have both male and female organs.
Asexual
Free-living flatworms reproduce asexually by fission. Flatworms have great ability to regenerate their damaged or lost parts of bodies. Sometimes, worms simply separate into pieces and each piece will grow into new worms. Parasitic flatworms do not reproduce asexually because their life cycle is more complicated than free-living flatworms.
Sexual
During sexual reproduction, two worms join and one worm deliver sperm to the other worm while receiving sperm from its partner at the same time. With in a few weeks, eggs hatch in small clusters.
Some roundworms are hermaphrodites as well.
phylum Nematoda
Sexual
Unlike flatworms, roundworms have separate males and females. Fertilization occurs inside the body of the female.
Movement
phylum Platyhelminthes
Free-living flatworms use cilia on their epidermal cells to help them glide through the water and over the bottom. Muscle cells are controlled by the nervous system which can help flatworms to twist and turn in their environment.
phylum Nematoda
The muscles help roundworms to move like a snake and their bodies can contract and push their way through the soil by thrashing around.
Free-living flatworms use cilia on their epidermal cells to help them glide through the water and over the bottom. Muscle cells are controlled by the nervous system which can help flatworms to twist and turn in their environment.
phylum Nematoda
The muscles help roundworms to move like a snake and their bodies can contract and push their way through the soil by thrashing around.
Respiration/Circulation/Excretion
phylum Platyhelminthes 
Flatworms lack circulatory or respiratory systems because they are so flat. Therefore, Oxygen and nutrients are transported to other tissue cells by diffusion. And flatworms also get rid of carbon dioxide and metabolic wastes by diffusion.
Freshwater flatworms such as planarians have structures called flame cells that help them get rid of water as they form a network that empties through tiny pores in the animals’ skin.
phylum Nematoda
Roundworms also lack respiratory and circulatory system. They transport nutrients, collect oxygen and get rid of metabolic waste by diffusion through their bodies.
Flatworms lack circulatory or respiratory systems because they are so flat. Therefore, Oxygen and nutrients are transported to other tissue cells by diffusion. And flatworms also get rid of carbon dioxide and metabolic wastes by diffusion.
Freshwater flatworms such as planarians have structures called flame cells that help them get rid of water as they form a network that empties through tiny pores in the animals’ skin.
phylum Nematoda
Roundworms also lack respiratory and circulatory system. They transport nutrients, collect oxygen and get rid of metabolic waste by diffusion through their bodies.
Digestion/Feeding
phylum Platyhelminthes
Flat worms are aquatic and free-living organisms. Some flatworms may be carnivores that feed on tiny aquatic animals and others maybe scavengers that feed on dead animals. Free-living flatworms have a gastro vascular cavity with one opening at the end of a muscular tube called a pharynx. Once pharynx sucks food into the gastro vascular cavity, intestine is formed with many branches along the body of the flatworm. In the intestines, enzymes break down food into small particles and these particles are taken inside the cells of the intestinal wall. Because intestine branches are spread along the body of the flatworm, tiny food particles diffuse to other body tissues. Unnecessary materials that cannot be digested exit through the mouth like cnidarians.
Parasitic flatworms feed on blood, tissue fluids, or pieces of cells inside the body of their host. Some of parasitic flatworms have pharynx to suck food into intestinal sacs where food is digested.
★ Tapeworms, which lives within the intestines of their host, do not have digestive tracts. They have suckers with absorb the food that has already been broken down by the host’s digestive enzymes.
phylum Nematoda
Roundworms have a long tube-shaped digestive tract with opening at the both ends. Food enters through the mouth and leaves through an opening called anus.
Free-living roundworms are carnivores that eat tiny animals. Some digest bacteria and fungi that break down dead organisms.
Some parasitic roundworms attach to the roots of green plants and absorb juices which damage many croups around the world and others live in plant tissues to collect nutrients.
Flat worms are aquatic and free-living organisms. Some flatworms may be carnivores that feed on tiny aquatic animals and others maybe scavengers that feed on dead animals. Free-living flatworms have a gastro vascular cavity with one opening at the end of a muscular tube called a pharynx. Once pharynx sucks food into the gastro vascular cavity, intestine is formed with many branches along the body of the flatworm. In the intestines, enzymes break down food into small particles and these particles are taken inside the cells of the intestinal wall. Because intestine branches are spread along the body of the flatworm, tiny food particles diffuse to other body tissues. Unnecessary materials that cannot be digested exit through the mouth like cnidarians.
Parasitic flatworms feed on blood, tissue fluids, or pieces of cells inside the body of their host. Some of parasitic flatworms have pharynx to suck food into intestinal sacs where food is digested.
★ Tapeworms, which lives within the intestines of their host, do not have digestive tracts. They have suckers with absorb the food that has already been broken down by the host’s digestive enzymes.
phylum Nematoda
Roundworms have a long tube-shaped digestive tract with opening at the both ends. Food enters through the mouth and leaves through an opening called anus.
Free-living roundworms are carnivores that eat tiny animals. Some digest bacteria and fungi that break down dead organisms.
Some parasitic roundworms attach to the roots of green plants and absorb juices which damage many croups around the world and others live in plant tissues to collect nutrients.
What are unsegmented worms?
Unsegmented worms are the simplest animals with bilateral symmetry to have a digestive system. Most of the members exhibit enough cephalization, or development of the anterior end. Unsegmented worms can be separated into two major phyla: phylum Platyhelminthes and phylum Nematoda. Free-living and parastic flat worms belong to phylum Platyhelminthes and round worm belong to phylum Nematoda. (Also phylum Rotifera)
Characteristics
Phylum Platyhelminthes is also known as flatworms because bodies are flatten dorsal-ventrally. Flatworm is acoelomate and contains three body layers: outer Ectoderm, middle Mesoderm, and inner Endoderm
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