Arthropoda General Characteristics, Classification and Examples | Free Biology Notes

Arthropoda General Characteristics, Classification and Examples

Arthropoda General Characteristics, Classification and Examples

After reading this article you will learn about Arthropoda General Characteristics, Classification and Examples

Arthropoda General Characteristics

  • Arthropods are the largest phylum of animals and they have jointed legs
  • Body is divided into head, thorax and abdomen
  • Head and thorax may be united to form cephalothroax
  • Jointed appendages which were used for locomotion, feeding, defense and sensory purposes
  • They body of arthropods is covered by chitinous exoskeleton
  • Exoskeleton does not grow and must be shed at intervals called molting or ecdysis
  • Sensory organs like eyes, antennae, statocyst and anal cerci are found
  • Digestive system is complete. it has 2 openings mouth and anus.
  • Respiratory system is well developed and respiration occurs through body surface, gills, trachea, book lung or book gills
  • Arthropods have an open circulatory system
  • Blood flows in open tissue spaces and hemocoel.
  • The perivisceral body cavity is called haemocoel as it is full of haemolymph
  • Excretion is brought about usually by green glands in aquatic forms and malpighian tubules in terrestrial animals.
  • Nervous system comprises of a nerve ring and double ventral nerve cord
  • Reproduction is sexual method
  • Arthropods are unisexuals and exhibit the phenomenon of sexual dimorphism.
  • Fertilization is usually internal but few aquatic form has external fertilization
  • Development may be direct or indirect
  • In direct development, the young resembles the adults and occur in the same habitat
  • In indirect development, independent larval stages occur which often show different feeding habits, live in different habitats and do not resemble the adults.
  • Parthenogenesis is also met in some insects like honey bees

Classification of Arthropoda

Class 1. Onychophora
Body is divisible into head and trunk.
Respiration: Tracheae. Excretion: nephridia. E.g. Peripatus

Class 2. Merostomata
Body is divisible into cephalothorax and abdomen.
Respiration: Book gills. Excretion: Coxal gland.
E.g. Limulus

Class 3. Arachnida
Body is divisible into cephalothorax and abdomen
Respiration: Book lungs. Excretion: Coxal glands and Malphigian tubules. E.g. scorpions, ticks, mites and spiders

Class 4. Crustacea
Body is divisible into cephalothorax and abdomen
Respiration: Gills or body surface. Excretion: Green glands
E.g. prawns, crabs, lobsters

Class 5. Chilopoda
Body is divisible into head and trunk
Respiration: Tracheae. Excretion: Malphigian tubules
E.g. centipedes

Class 6. Diplopoda
Body is divisible into head, thorax and trunk
Respiration: Tracheae. Excretion: Malphigian tubules
E.g. millipedes

Class 7. Insecta
Body is divisible into head, thorax and abdomen.
Respiration: Tracheae. Excretion: Malphigian tubules
E.g. Musca, Lepisma

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Rajkumar is a lecturer from TamilNadu, India. He holds a master degree in botany. Passionate, Blogger, Video Creator, Photography. He helps the students for advancement and provide Biology Materials. Life Motto: Live while you can! Teach and inspire while you could & smile while you have teeth

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