UNSEGMENTED WORMS PHYLUM PLATYHELMINTHES PHYLUM NEMATODA

Transcription

1 NAME: UNSEGMENTED WORMS PHYLUM PLATYHELMINTHES PHYLUM NEMATODA DATE: BLOCK: Why do we call Platyhelminthes and Nematoda UNSEGMENTED WORMS? PHYLUM PLATYHELMINTHES (FLATWORMS) - Platy means and helminthes refers to. - Flatworms are flattened and are usually no more than a few millimeters thick. But flatworms can get extremely long the record is set by a tapeworm found to be 39 meters long!!! - Flatworms have symmetry. - They also have an easily distinguishable and end. - Flatworms are found in environments. - There are 3 Classes of flatworms: o Class - planarians and marine flatworms o Class - flukes o Class - tapeworms PARASITIC Mr. Lau Page 1 of 7 Biology 11

2 FEEDING Please label this planarian: - Free-living planarians have a gastrovascular cavity with just opening. At the end of this opening, there is a muscular tube called a where the is. - The gastrovascular cavity branches off and forms. - Planarians are either or scavengers. - Most flukes and tapeworms are parasitic so feeding is much simpler. These parasites may feed on or already digested food from the of the host. These animals can attach themselves to a host with and/or. These structures are found on the or head of a tapeworm. Draw the scolex of a tapeworm: Draw the scolex of a tapeworm: - Because of the parasitic lifestyle the digestive tract that is much. Mr. Lau Page 2 of 7 Biology 11

3 RESPIRATION, INTERNAL TRANSPORT, AND EXCRETION Why can flatworms rely on diffusion for respiration and waste removal? Planarians also have that get rid of excess. There cells are precursors to the kidneys found in vertebrates. RESPONSE - We can easily identify the end of a planarian because of a process called where a head is formed. This head contains a rather simple. From this structure, a ladder-like network of run along the body - How is the environment detected by a flatworm (planarian)? - Parasitic cestodes and trematodes do not have much need for a nervous system since their lifestyle is very. SUPPORT SYSTEM AND MOVEMENT What 2 things do planarians use to move around? Mr. Lau Page 3 of 7 Biology 11

4 REPRODUCTION - Planarians are and can produce both and. Outline SEXUAL reproduction in planarians: Outline ASEXUAL reproduction in planarians: How do people become infested with parasitic flatworms? How do tapeworms reproduce? What structures are involved? Mr. Lau Page 4 of 7 Biology 11

5 PHYLUM NEMATODA (ROUNDWORMS) - Nematoda = thread-like - Roundworms are probably the most abundant of all multicellular animals chances are, you make contact with a roundworm everyday! - There are both free-living and species of roundworms living in all types of environments. - For the first time, we see the anatomical features of a tube within a tube body plan (a pseudocoelom). FEEDING What do roundworms eat? How is the digestive tract of a roundworm different from that of a flatworm? How are roundworms harmful to certain agricultural products? Mr. Lau Page 5 of 7 Biology 11

6 RESPIRATION, INTERNAL TRANSPORT, AND EXCRETION Once again, respiration (oxygen), waste excretion (ammonia and carbon dioxide), and internal transport (of nutrients) depend on diffusion to move through body walls or within the body. RESPONSE - Roundworms have several which are groups or clusters of nerve cells. Nerves extending from these clusters run the length of the body and transmit sensory information and control of movement. SUPPORT SYSTEM AND MOVEMENT - The fluid-filled pseudocoelom acts as a skeleton. - Roundworms have strips of muscle down the length of their body. How does movement of a roundworm on land differ from movement of a roundworm in water? REPRODUCTION Roundworms generally have sexes and reproduce sexually. Thus, each sex has a different set of reproductive organs. Fertilization takes place the body of the female. Mr. Lau Page 6 of 7 Biology 11

7 Outline the stages of the life cycle of a common parasitic roundworm, the human ascarid (Ascaris lumbricoides): Stage What happens? Where does this happen? What parts of the human body are involved? ROUNDWORMS AND US Identify and describe some diseases caused by roundworms. Mr. Lau Page 7 of 7 Biology 11