Chapter 28 Introducing Invertebrates
Describe the parasitic flatworms, and give the life cycle of both blood fluke that causes Schistosomiasis and the pork tapeworm.
They are flukes and tapeworms of parasitic flatworms which are highly modified for the parasitic mode of life. The flukes and tapeworms both utilize a secondary or intermndiate host to transport species from primary host. The primary host is infected with the sexually mature adull ; the secondary host contains the larval stage or stages. The life cycle of a blood fluke schistosoma is a micrograph of the schistosoma which the infection of humans is caused by blood flukes the schistosoma is an extremely prevalent disease in Egypt and the blood fluke- schistosoma occurs in the middle east. Tapeworms have complicated life cycles that usually involve several hosts the life cycle of the pork tapeworm, taenia solium, which involves the human as the primary host and the pig as the secondary host. The life cycle includes a human-primary host and a pig-secondary host, the adult worm is modified for its parasitic way of life. It consists of a scolex and many proglottids, which became bags of eggs.
Chapter 29 Vertebrate Evolution
1. What four characteristics do all chordates have at sometime in their life history? A dorsal supporting rod called a notochored second- a dorsal tubular nerve chord, third- pharyngeal pouches, and fourth-postanaltail.
9. What is the significance of wings? In what otherways are birds adapted to flying? The forelimbs are modified as puddles which birds fly by flapping their wings Flight requires the sdense organs and nervous system to be well developed. Birds have acute vision and well-developed brains. Newly hatched birds require parental care before they are able to fly away. They navigate by day and night. The benefit of air sacs is that they lighten the body and bones for flying.