What are the 3 properties of arthropods

Difference Between Annelida and Arthropoda

Key difference - Annelida versus Arthropoda

Annelida and Arthropoda are two tribes of the Animalia kingdom. Both Annelida and Arthropoda are made up of segmented animals. The Main difference between Annelid and Arthropoda that is Annelida is made up of a hydrostatic skeleton, while Arthropoda is made up of an exoskeleton made of chitin. Animals in both phyla are divided into different classes based on their diversity. The three classes of the Annelida tribe are Polychaeta (sea bristle worms), Oligochaeta (water and land worms) and Hirudinea (leeches). The five classes of the Arthropoda tribe are Crustacea (shrimp, crabs, and lobsters), Arachnida (spiders, ticks, mites, and scorpions), Chilopoda (Centipedes), Diplopida (Millipedes), and Insecta (bees, butterflies, roaches, and beetles).

Important areas

1. What is Annelida?
- definition, characteristics, classes
2. What is Arthropoda?
- definition, characteristics, classes
3. What are the Similarities Between Annelida and Arthropoda
- Overview of general functions
4. What is the difference between Annelida and Arthropoda?
- Comparison of the main differences

Key Terms: Animalia, Anneida, Arachnida, Arthropoda, Chilopoda, Crustacea, Diplopoda, Insecta, Hirudinea, Oligochaeta, Polychaeta

What is Annelida?

Annelida refers to a kingdom of Animalia made up of segmented worms with elongated body shapes. About 9000 species of annelids have been identified to date. Most annelids are aquatic and some are terrestrial. Annelids are wild animals with bilateral symmetry. Annelids are triploblastic coelmates that have a true coelom. The coelom is divided by internal septa. That is, annelids have a fully segmented body called metameric segmentation. The tissues of the body make up organs. The three separate parts of an annelid's body are a prostomium, a trunk, and a pygidium. Annelida comprises a complete digestive system with a mouth and an anus. Breathing generally occurs through the surface of the body. The nervous system consists of an anterior nerve ring with ganglia and a ventral nerve cord. Annelids are made up of a closed circulatory system with multiple hearts and blood vessels. It is excreted by nephridia. Annelids can be either hermaphroditic or gonochoric. Internal or external fertilization can occur in annelids. The larval stages of the annelids can be zooplankton.

Figure 1: An earthworm

The three classes of annelids are Polychaeta, Oligochaeta, and Hirudinea. The polychaeta consists of marine bristle worms. The oligochaeta is made up of earthworms in the water or on land. The Hirudinea is made up of leeches. An earthworm is shown in Illustration 1.

What is Arthropoda?

Arthropoda refers to another kingdom of Animalia made up of animals with articulated followers and a chitinous exoskeleton. Arthropods can be aquatic, land, or aerial forms. Arthropods are triploblastic animals whose body cavity is filled with blood or hemolymph. Arthropods are therefore hemocoelomatics. In addition, the arthropod's circulatory system is an open circulatory system that consists of a heart and an artery. The body of the Arthropoda is divided into the head, chest and abdomen. The head consists of pairs of antennae and compound eyes. Arthropoda was the first group of animals to develop a head. The joint attachments can appear in pairs. Since the body of the arthropod is covered with a chitinous exoskeleton, they regularly secrete its exoskeleton in order to achieve body growth. This process is known as molting or ecdysis. Arthropods consist of a complete digestive system with anus and mouth. The mouth is modified for chewing or biting. Arthropods breathe through their gills, windpipes, or book lungs. Land arthropods are excreted through Malpighian tubules. In aquatic arthropods, excretion occurs through coxal or green glands. The arthropods are unexexual animals.

Figure 2: A bee

The five types of arthropods are Crustacea (shrimp, crabs, and lobsters), Arachnida (spiders, ticks, mites, and scorpions), Chilopoda (millipedes), Diplop (millipedes), and Insecta (bees, butterflies, cockroaches, and beetles). A bee is shown in Figure 2

Similarities Between Annelida and Arthropoda

  • Annelida and Arthropoda are two tribes of the Animalia kingdom.
  • Both Annelida and Arthropoda are made up of bilateral symmetry.
  • Both Annelida and Arthropoda are made up of triploblastic animals with three germ layers.
  • Both Annelida and Arthropoda have the organ system level.
  • Both Annelida and Arthropoda are made up of segmented body structures.
  • Both Annelida and Arthropoda are made up of a hydrostatic skeleton.
  • Both Annelida and Arthropoda consist of a cerebral ganglion with a ventral nerve ligament.
  • Both animals consist of a mouth at one end of the body and an anus at the other end.
  • Both animals are subject to sexual reproduction and fertilization can be either internal or external.
  • Both animals have similar types of larvae.

Difference Between Annelida and Arthropoda

definition

Annelida: Annelida refers to a strain of animals made up of coelomats with an elongated, segmented body.

Arthropoda: Arthropoda refers to a strain of animals made up of hemocoelomatics with a segmented body, common followers, and a chitinous exoskeleton.

Commonly called

Annelida: Annelids are commonly called segmented worms.

Arthropoda: Arthropods are commonly referred to as articulated animals.

Clear head

Annelida: Annelida lacks a distinct head.

Arthropoda: The body of the Arthropoda differs in the head, thorax and abdomen.

Segmentation of the body

Annelida: Annelida is made up of a fully segmented body called metameric segmentation.

Arthropoda: Arthropoda does not consist of a fully segmented body.

Common attachments

Annelida: Annelida is missing limbs.

Arthropoda: Arthropoda is made up of connected appendages.

Body cavity

Annelida: Annelida is made up of Coelomat animals.

Arthropoda: Arthropoda consists of hemocoelomatized animals.

skeleton

Annelida: Annelida consists of a hydrostatic skeleton.

Arthropoda: Arthropoda consists of both a hydrostatic skeleton and an exoskeleton.

Cycle

Annelida: Annelida consists of a closed circulatory system.

Arthropoda: Arthropoda consists of an open circulatory system.

Hearts

Annelida: Annelida is made up of several simple hearts.

Arthropoda: Arthropoda is made up of a heart.

Senses

Annelida: Annelida consists of antennae, palps, eyes, statocysts, lateral organs, and umbilical organs.

Arthropoda: Arthropoda is made up of antennae, statocysts, simple eyes, and compound eyes.

Respiratory gas exchange

Annelida: The breathing gas exchange of the Annelida takes place through the skin or parapodia.

Arthropoda: Arthropoda's respiratory gas exchange occurs through gills, trachea or book lungs.

excretion

Annelida: Annelida is excreted through nephridia.

Arthropoda: Excretion occurs through the coxal gland of the Malpighia tubules.

Separation of the sexes

Annelida: Annelida is made up of hermaphroditic animals.

Arthropoda: Arthropoda is made up of unisexual animals.

Conclusion

Annelida and Arthropoda are two tribes of the Animalia kingdom made up of invertebrates. Annelida and Arthropoda share many characteristics. Both are triploblastic animals with bilateral symmetry. Both consist of a segmented body. Both Annelida and Arthropoda are made up of a hydrostatic skeleton. However, Arthropoda is made up of a chitinous exoskeleton. This is the main difference between Annelida and Arthropoda.

Reference:

1. "Phylum Annelida: General Characteristics and Classification". Notes on Online Biology, June 10, 2017, available here. Retrieved August 21, 2017.
2. "General Characteristics and Classification of Arthropoda". Microbiology Notes, March 8, 2016, available here. Retrieved August 21, 2017.

Image courtesy:

1. "Regenwurm1" By Michael Linnenbach - first upload in de Wikipedia on 09:58, 16. Feb 2005 by Michael Linnenbach, (CC BY-SA 3.0) via Commons Wikimedia
2. "Bee-apis" By Maciej A. Czyzewski - Own work (GFDL) via Commons Wikimedia