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Flatworms & roundworms

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1 Flatworms & roundworms
By: Nayarit Ayala and Marleni Cruz

2 Flatworms Platyhelminthes

3 Flatworms are flat, soft bodied, ribbon shaped unsegmented, contain no body cavity, but they do have digestive cavity. They are bilateral symmetrical, while having only one opening. Flat worms have layers of tissues that surround their central gut. They are part of the acoelomates, and are considered hermaphroditic. Their type of cell layers are: an ectoderm, which is the outer covering, an endoderm, which is the lining of digestive spaces, and a mesoderm which is in between the other two. No skeleton, has tiny bristles called cilia that help it move, it has a combo of digestive & excretory system, takes food and gets rid of wastes through the same opening, has a simple nervous system with 2 nerve cords running down either side, has 2 simple brains called ganglia ( bundles ) and 2 eyespots that sense light. takes in oxygen but has no formal respiratory system Structure

4 diversity Classification: What’s special about flatworms?
Domain: Eukarya Kingdom: Animalia Phyla: Platyhelminthes Class: Turbellaria Order: Seriata Family: Planariidae Group: Dugesia What’s special about flatworms? Flatworms can regenerate if they are cut, they will grow another head if their cut is head. They also have a layer which is in the middle, that has unorganized cells.

5 Mode of nutrition The organisms obtain nutrients by feeding on blood, tissue fluids, or pieces of cells inside the bodies of their hosts. All the nutrients are transported into their single opening that leads directly to the digestive system. Studies show that platyhelminthes go through anaerobic metabolism, which is not being dependent of oxygen. Oxygen is usually available. And it eats small worms, insects and microscopic matter. they've developed various feeding methods, turbellarians can feed on organisms larger than themselves like annelids, arthropods and mollusks. they have extracellular and intracellular digestion. when intra, hematin is deposited which is a pigment from hemoglobin.

6 Reproduction Flatworms reproduce sexually by having both a male and female part. Each part that is split becomes a separate worm, and they reproduce asexually when it splits. It makes them reproduce asexually. They have a cocoon that carries eggs, swells in their body then , releases the cocoon, and attach it to water weeds. The cocoon has yolk, which nourishes the eggs. The eggs are then hatched.

7 Ecological significance
Importance of the Organism Interactions with Humans Through their large surface compared to their volume they can exchange gases like carbon dioxide, oxygen and ammonia across bodies. Flatworms can adapt to many conditions, which makes them able to adapt to an enormous variety of habitats. They play important roles for healthy streams, ponds, and lakes. They also provide food for animals, like dragonflies, when they are young. Flatworms act as parasites in the human body, especially in their intestines and digestive tracts. They increase the chances for organic farming. They increased the popularity of raw cooked foods, such as the imports of meat, seafood, and vegetables.

8 Ecological significance (cont..)
Symbiotic relationships with other organisms Illnesses they may cause They need symbiotic relationships to survive from fatty acids. Chronic Illness Megaloblastic Anemia Increase for bladder cancer Schistosomiasis Tapeworm disease (cestodiasis) Cysticercosis Joint Pains Headaches Fevers

9 Uniqueness Flatworms can regenerate if a part of their body is lost.
They reproduce with both sexual parts. They can be up to 50 meters long. They need symbiotic relationship to survive from fatty acids. They have a well developed nervous system.

10 Roundworms Nematoda

11 Roundworms are bilaterally symmetric
Roundworms are bilaterally symmetric. Eyespots are spots on the worm that react to changes in light. When the light moves, it sends signals to the worm to move. Roundworms use some of their nerves to detect changes in light. A roundworm is thin, round, smooth and can be up to four feet in length. A roundworm has an anus at its rear end and a series of excretory tubes that end in an excretory pore. structure

12 Mode of nutrition Roundworms usually eat algae, bacteria, protozoa and fungi, some are filter feeders, eating the waste of other creatures. They thrive their nutrition in sediment and around plant roots. Free living roundworms feed on the decay for organic matter and contribute to its breakdown in the soil. They serve as decomposers and make nutrients for larger organisms.

13 reproduction Roundworms sexually reproduce, and they have eggs and sperm. The male has sperm which pass through the spicule over 200,000 eggs can be deposited at once in the soil once they are fertilized. Females have an ovary, and they are meant to hold the eggs in an oviduct, then they get passed into the uterus, after they lay their eggs in the soil once they’re fertilized.

14 Ecological significance
Importance of organism Interactions with humans Nematodes’ feeding, digestion, and excretion allows minerals and nutrients vital to plants and other organisms to be recycled from bacteria, fungi and decaying organic matter and returned to the soil where they are readily accessible. They form a large part of the base that supports the complexity of life on earth.  As consumers or more specifically decomposers, free-living roundworms recycle decaying rotting organic matter present in abundance in almost all environments.  They are a crucial link in the chain of energy production and matter recycling. They cause major diseases and infections to humans.

15 Ecological significance (cont..)
Illnesses they may cause Onchocerciasis Malaria Fevers Joint pains Headaches Diarrhea Nausea Abdominal cramps

16 Uniqueness Roundworms have a thick cuticle that covers their bodies and is shed in order to allow for growth. Located between the cuticle and the pseudocoel are muscles that run the length of the nematode. These muscles push on both the cuticle and the pseudocoel and create a kind of hydrostatic skeletons. Unlike most animals whose nerve cells branch out to each individual muscle cell, nematode’s muscle cells branch toward the nerve cells.

17 examples Ascaris (intestinal roundworm) – they’re found in humans and are present mostly in unsanitary areas without plumbing Hookworm – they’re found in warm regions and burrow through skin they came in contact with their hook shaped anterior ends allow them to latch onto the intestinal wall of their hosts and feed on blood. Trichinella is passed to humans through poorly cooked pork. Elephantiasis is a human disease caused by filaria worms. It is characterized by gross swelling and malformations due to blockage of lymph vessels by the parasite. A mosquito is a secondary host.

18 references (Brenda Priddy, 1999) Invertebrates: Flat Worms. (n.d.). Rader's BIOLOGY 4 KIDS.COM. Retrieved February 24, 2012, from Roundworms. (n.d.). University of Maryland Medical Center | Home. Retrieved February 24, 2012, from flatworm. (2012). In Encyclopædia Britannica. Retrieved from integument. (2012). In Encyclopædia Britannica. Retrieved from Raven, P. H., & Johnson, G. B. (1996). Biology. Dubuque, IA: Wm. C. Brown Publishers.

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