🦐 Arthropoda Classification

Classification

• Phylum Arthropoda is further divided into 7 Classes.

  

  

Relationship with Class Insecta

• Arthropod were initially aquatic and later became terrestrial as proved from class Trilobita.

Class: Insecta (Hexapods)

• Insects occupy more than 97% of total population of Phylum Arthropoda and belongs to sub phylum Hexapoda.
• The word insect is derived from Latin word insectare (in means internal and sect means cut) which means “to cut into”. This refers to the characteristic appearance of insects as if they have been “cut into” three sections.
• Insects are tracheated arthropods whose body is divided into three regions (tegmosis) viz. Head, Thorax and Abdomen.

• Insect ⇒ Head (Usually 6 segments fused) + Thorax (3 segment distinct) + Abdomen (11-12 segments distinct)
• Head bears single pair of antenna and a single pair of mandibles and two pairs of maxillae, the second pair fused medially to form the labium. Head also bear one pair of compound eyes.
• Thorax carries three pairs of jointed legs (one pair on each segment of thorax) and generally two pair of wings (one on meso and one on meta thorax). Because of three pairs of legs insects are commonly known as Hexapods.
• It means thorax has main function of locomotion. But one pair (2 only) of trachea also on thorax therefore it has minor function of respiration. Remaining trachea are on Abdomen.
• The abdomen is devoid of ambulatory appendages (means legs are absent on abdomen) and the genital opening is situated near the posterior end of the body. Abdomen also has trachea for respiration. Abdomen has main function of Respiration and Reproduction.
• Postembryonic developments rarely direct and metamorphosis usually occurs.

  

• Possess exoskeleton made up of hard cuticle made of chitin which plays important role for survival.
• Excretion is mainly by malpighian tubules which help in maintaining ionic balance.

Explore More 🔭

🟢 https://youtu.be/2ivZ6GSaK1M

- Insecta - Introduction: K.N. Ragumoorithi, V. Balasurbramani & N. Natarajan
- A General Textbook of Entomology (9th edition, 1960) – A.D. Imms (Revised by Professor O.W. Richards and R.G. Davies). Butler & Tanner Ltd., Frome and London.
- The Insects- Structure and Function (4th Edition, 1998) – R.F. Chapman. Cambridge University Press
- Wikipedia
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