Classification of invertebrate zoology (phylum arthropoda)

 

Phylum Arthropoda;

General Characteristic of Arthropoda;

1.     The arthropoda are tripoblastic as well bilateral symmetrical.

2.     Arthropoda are found in all forms of habitats such as on land in water and soil.

3.     They exhibit jointed limbs.

4.     Their body is segmented into three regions for instance  thorax, head as well abdomen.

5.     They are having body cavity filled with blood called haemocoel. However their blood is white in colour.

6.     They exhibit hard exoskeleton is hardened that is made of chitin.

7.     The arthropod have a well-developed central nervous system.

8.     They are having well develop head with sensory organs and brain, while they exhibit compound eyes with mosaic vision.

9.     They are having complete digestive along-with mouth and anus at both ends of the body.

10.                    They possess an open circulatory system with ventral notochord and dorsal heart.

11.                    The aquatic animals take respiration through their body surface or by gills while the terrestrial animals take respiration through their lungs.

12.                    The arthropoda exhibit separate sexes as well sexual dimorphism.

 

Organization of phylum arthropoda

The  phylum arthropoda are classified into the following classes.

Class 1. Crustacea;

1.     The crustacea  are terrestrial, aquatic and parasitic in nature.

2.     In crustacea species the head has fused with the thorax region recognized as the cephalothorax.

3.     In crustacea the phenomenon of respiration take place by gills as well general body surface.

4.     The crustacea exhibit five pairs of appendages and two pairs of antennae .

5.     The excretion occur in these invertebrates  through green glands and antennal glands.

6.     They exhibit a pair of compound eyes as well gonopores.

7.     In theses invertebrates direct development occur.

8.     The class crustacea is further differentiated into the six orders.

Class 2. Myriapoda;

1.     They are habitually terrestrial.

2.     They are having elongated body along-with numerous segments.

3.     They posses head with two jaw pairs one pair of eyes and antennae,

4.     The numerous legs are found in myriapoda.

5.     The upper lip of the myriapoda  mouth comprises of labrum as well epistome while the lower lip comprises a pair of maxillae.

6.     The myriapoda having a pair of mandibles inside the mouth.

7.     In mrriapoda the respiration occur through trachea while excretion occurs through malpighian tubules.

8.     The scolopenda and  julus belong to this class.

The Class Myriapoda is further differentiated into the following orders.

Order 1.Pauropoda

Order 2. Symphia

Order 3. Chilopoda

Order 4.Diplopoda

Class 3. Hexapoda;

1.     The members of Hexapoda are mostly terrestrial and their body is differentiated into the head thorax as well abdomen.

2.     Pre segmental acorn bears on their head surface, while there are divided into the three segments.

3.     The abdomen portion lies at the 7 to 11 segments.

4.     The three pair of appendages and one pair of compound eyes are found in them.

5.     The respiration phenomenon occur in them through the gills and trachea.

6.     The excretion in Arthropoda take place through the Malpighian tubules.

7.     Indirect development take place, while larval stage is found.

8.     The ants, Mosquitoes and Tabernus are include in hexapoda.

The Class Hexapoda is further divided into two classes;

Order 1. Entognatha

     Order 2.Insecta

Class 4. Chelicerata;

1.     The member of chelicerta  are mostly present on land and their body is differentiated into abdomen as well cephalothorax. The abdomen of chelicerata differentiated into the 13 segments.

2.     The antennae is not found in chelicerata.

3.     They exhibit four pair of interior appendages.

4.     In chelicerate the respiration take place through the gills and trachea.

5.      The process of excretion occur through the malpighian tubules.

6.     The limulus and Aramea belong to chelicerate.

The class  Chelicerata is differentiated into the following orders:

Order1.Merostomata

Order 2.Pycnogonida

Order 3.Arachnida

Class 5.Onychophora

1.     They are small sized, terrestrial invertebrates.

2.     They shows segmentation in their body.

3.     In onychophora the process of excretion occur through nephridia.

4.     The respiration take place in these invertebrates through the trachea.

5.     The paripatus belong to this class.

Class 6.Trilobitomorpha

1.     The trilobitomorph are extinct or  primitive arthropods.

2.     In the Paleozoic era the triobitomorpha were abundances.

3.     Their body was divided into three lobes for instance two lateral lobes and one median lobe.

4.     They were exhibit one pair of compound eyes and a pair of antennae on their head.

5.     There was no structural differentiation in their body parts.

6.     Their body was distinguished into the pygidium, thorax and head,while appendages were biramous.

This class further divided into only one order.

Order 1.Trilobita..