General Characteristics and Classification of Aschelminthes

By Nitul Kalita
A brief Introduction to phylum Aschelminthes




There are several classes of animals where a pseudocoel is the area inside the body. It is not a true coelom because it is not filled with mesodermal epithelium, and it represents an embryonic blastocoel that survives. Such animal classes are known as pseudocoelomates (presence of a cavity, the pseudocoel, between the intestine and the body wall), and are often classified within a single superphylum aschelminthes. Gegenbaur (1859) created a group nemathelminthis to place some pseudocoelomates animal.


General Characters-

1. Mostly aquatic, free living or parasitic. 

2. Usually small, even microscopic.

3. Body slender, vermiform, unsegmented, flator cylindrical, bilaterally symmetrical and triploblastic.

4. Organ system grade of body organization. 

5.Head not distinctily formed with well-defined sense organs. 

6. Body wall is with a syncytial or cellular epidermis externally covered with thick cuticle of scleroprotein. 

7. Cilia absent except anterior cilia of rotifers. 

8. Musculature includes mostly longitudinal fibres. 

10. Body cavity pseudocoel not lined by mesoderm. 

11. Digestive canal complete with mouth, specialized pharynx, straight non-muscular intestine and posterior or anus. 

12. No circulatory and respiratory systems.




Classification-

Phylum Nematoda have 2 Classes-

1. Apasmida

2. Phasmida


Class 1 Aphasmida-

i. Usually two testes are are present in males.
ii. Phasmids (sensory organ) are absent.
iii. Cephalic organs, setae and hypodermal glands are present.
iv. Most species are free living and some are parasitic.
v. Amphids(Anterior sensory organ) are not pore like.


Class 2 Phasmida-

i. Phasmids are present
ii. Amphids open to outside by pores.
iii. Males contain single testes.
iv. Most species are parasitic and free living species mainly inhabit soil.
v. Epidermal cell uni or multinucleate; cuticle two or four layered.


Comments

Post a Comment

Popular posts from this blog

Study of Euglena | General characters and classification

By Nitul Kalita
Image
Study of Euglena with General character and classification- General characters-  1. Habitat  : it is found in a stagnant fresh water such as pools and ponds which contain decaying organic matter. 2.  Locomotion  : Euglena moves by the whiplike action of a single flagellum. As Waves pass al ong the flagellum from the base to the tip. The organisms rotate as it moves. It can also move by the contraction of fibrils in its body called Myonemes. These contraction brings about a sequence of changes in the shape and cause euglenoid movement. 3. Euglena viridis is a green and photo-autotrophic organism.The Euglena absorb carbon dioxide from the water in which he lives and energy from the sunlight to carry photosynthesis. It make up its nitrogen requirements by absorbing nitrogenous substances such as amino acids from the water. 4. Structure : Euglena is a microscopic organisms of about 0.125mm long. It h
Read more

General Characteristics and Classification of Protozoa

By Nitul Kalita
Image
A Brief introduction to Phylum Protozoa The Protozoa are heterogeneous gathering of somewhere in the range of 50,000 cell or single-cell life form discovered worldwide in many environments. Protozoa signifies 'first creature' the least difficult type of creature life.  Protozoa are unicellular microorganisms (eukaryotes) that need cell dividers. They are found in  marine living space or soil, in new water bodies, advantageous, a few structures are parasites in other  life forms. Protozoa relies upon nourishment, temperature, pH, and some relies upon daylight.  Protozoa were characterized as unicellular protists with creature like conduct, for example, development.  Protozoa were viewed as the accomplice gathering of protists to protophyta, which have plant-like  conduct, for example photosynthesis. The term protozoan has gotten exceptionally hazardous due to the presentation of current ultra basic, biochemical, and hereditary systems, which have app
Read more

Life Cycle and pathogenicity of Wuchereria bancrofti

By Nitul Kalita
Image
Life Cycle and pathogenicity of Wuchereria bancrofti Classification- Phylum- Nematoda Class- Phasmida Order- Filaroida Genus- Wuchereria Species- bancrofti Wuchereria bancrofti  is commonly known as filarial worm. This worm causes filariasis in humans. The name of this worm is given Wuchereria bancrofti in honor of the two scientists Wucherer and Bancroft who made considerable contribution in studying the disease caused by these worms. LIFE CYCLE OF WUCHERERIA Wuchereria is a heterogeneous parasite which completes its life cycle in two different hosts namely man and female culex mosquito. Life cycle in Man- This cycle is also known as Human Phase. The process of copulation takes place in the lymphatic system of the human. The male and female worms copulate when they are present in the same lymph gland. The female worms are ovoviviparous that is they produce eggs which hatch within the body of the female without obtaining nour
Read more