PARASITIC TAPEWORMS AND ANTHROPODS By George Chiluba

TAPEWORMS

Tapeworms are obligate parasites, which means that the adult stage cannot survive away from the host. They are zoologically classified in the Phylum Platyhelminthes (literally "flat worms") and Subphylum Cestoda. All tapeworms have indirect life cycles, which means that they utilise more than one host. The final host harbors the adult or sexually mature stage of the worm, whereas the immature stages occur in one or more intermediate hosts. These immature stages occur in a variety of forms and sizes, but can all broadly be described as "bladder worms" or "cysts".

 BIOLOGY OF TAPEWORMS

Reproduction: A tapeworm body consist of proglottids. It grows as these repeating body units and bud form the region behind the scolex. The tapeworm can fertilize itself (hermaphroditic).

Nutrition: They have a saprozoic mode of feeding (it absorbs digested liquid food from the intestine of the host) and the mode of respiration is anaerobic

Life History

  

       
Conservation Values and or role of tapeworms in the ecosystem

• Cause diseases known as cestodiasis which can damage the brain.
• Exert selective pressures upon their host populations that increase host genetic diversity.
• Shapes community structure through their effects on trophic interactions, food webs, competition, biodiversity, and keystone species.
• Biological control

ARTHROPODS

 INTRODUCTION

 According to Starr et al. 2009, there are four main groups of arthropods; Hexapoda (insects),   Myriapoda (millipedes and centipedes), Crustacea (lobsters and shrimps), Chelicerata (spiders, scorpions, mites, ticks, and horseshoe crabs).  Arthropods are characterized by having a segmented body, jointed appendages, and a hard external skeleton.

Segmented Body; Arthropods have three distinct body segments i.e. the head, the thorax, and the abdomen.

Jointed appendages:  An appendage is a structure that extends from the arthropod’s body wall.

Unlike the parapodia and setae of annelids, arthropod appendages have joints that bend. The name Arthropoda means “joint footed.”

Exoskeleton: The rigid outer layer of the arthropod body is called an exoskeleton, which is composed primarily of the carbohydrate chitin for protection against predators and helps prevent water loss.

 Biology of Arthropods

Reproduction; Most arthropods reproduce only sexually, though some can produce offspring from unfertilized eggs. Eggs are usually laid outside the female’s body and immature animals that hatch from the eggs generally receive no parental care.

 Life History

ROLES Pollination e.g. bees Natural Pest Control i.e. centipedes and millipedes Maintaining ecological balance through preying on  and being  preyed on Essential links in food chains Nutrient recycling Food sources for humans and many other animals Symbiotic relationships i.e.  Some can remove parasites , cleaner shrimp Transmission of diseases such as relapsing fever, typhoid, tuberculosis, diarrhea, amoebic dysentery and cholera.

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