Aschelminthes
Question 1: Write the sense organs of phylum Aschelminthes.
Answer:
Papillae, Amphids and Phasmids are the sense organs of phylum Aschelminthes.
Question 2: Which is the causal organism for the disease ascariasis?
Answer:
Ascaris is an endoparasite which causes asacariasis.
Question 3: What are the symptoms of ascariasis?
Answer:
Fever, abdominal swelling, abdominal discomfort, and abdominal cramping are the symptoms of ascariasis.
Question 4: Give examples of Aschelminthes.
Answer:
Ascaris, Wuchereria, and Dracunculus are some of the examples of phylum aschelminthes.
Question 5: Write the difference between male Ascaris and female Ascaris.
Answer:
- Males are smaller than females.
- The posterior end of the male is curved while that of the female is straight.
Phylum Aschelminthes
Animals are those organisms which are eukaryotic, multicellular and heterotrophic in their mode of nutrition. Animal cells do not have cell walls. Except for a few, most animals are mobile. Multicellular animals are often called metazoa and have been divided into two branches: Parazoa and Eumetazoa. In Parazoa, the animal’s body is formed of loosely aggregated cells. These animals have poorly differentiated tissues and have no organ or digestive cavity (e.g., sponges). However, in Eumetazoa, the cells are properly arranged into tissues and organs. Their digestive track is the mouth but with or without an anus.
Eumetazoa is further classified on the basis of
- the number of germ layers present in the embryo
- the symmetry of the body of the organism
- the mode of origin of mouth
Those animals which have two germ layers in the embryo are called diploblastic animals and those having three germ layers are called triploblastic animals. Further classification of animals is on symmetry, on basis of mouth origin, based on the presence or absence of body cavity or coelom. Animals do not have cell walls and chlorophyll. The central vacuole is absent. They store food as glycogen and fat. Animals can transmit impulses due to the presence of nerve cells. Sponges do not have nerve cells. Centrioles are present.