Monday, August 20, 2012

STPM Biology - chapter 6: Revision essay question 2

2. With reference to a named endoparasite,state the main adaptive features that enable it to live in its host.

Answer


An example is Taenia, an endoparasitic tapeworm in human intestine.
                      Main adaptive features are:
                    -Posses organs such as hooks and suckers for attachment to gut wall of host.
                    -Body covered with outer thick cuticle resistance to hydrolysis by host enzymes.
                    -Reduction of sense, digestive and locomotory organs as the parasite is less dependent 
                     on them. 
                    -Able to respire anaerobically in the gut.
                    -The tapeworm has a long flat ribbon-shaped body (up to 12m long) to increase surface  
                      area for absorption of pre-digested food.
                    -The body consists of numerous proglottids. Each proglottid contains male and female 
                      reproductive organs (hermaphrodile) allowing cross fertilisation or self-fertilisation if                                   
                      only tapeworm is present and production of many eggs.
                    -A secondary host is used as a vector for wider dispersal.

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