phylum arthropoda

Phylum Arthropoda

Phylum Arthropoda

                This is the largest of kingdom animalia. About ¾ of all known animals are arthropods

Characteristics of phylum arthropoda

  • They are triploblastic coelomates
  • They are mathematically segment
  • They are bilaterally symmetrical
  • The coelom is much reduced, and the main body cavity is called a haemocoel in it, blood moves freely over the tissues through a series of spaces (i.e. they have open blood circulation).
  • Their Central nervous system consists of a pairs pre-oral ganglion connected by nerves called commissures to a central nerve cord
  • Their excretory system consists of coelomoducts instead of (nephridia as in annelids). The coelomoducts are tubes which open to the outside of the organism at the base of appendages.
  • Arthropods posses Malpighian tubules which open to the mid and hind gut for excretion.
  • Each segment bears a pair of jointed appendages (arthros = Jointed) (poda = legs) this serves purposes like locomotion feelings and sensation.
  • There is a dorsal heart and their circulation, and the body is differentiated into a head thorax and abdomen
  • Many larva forms exist within the phylum; there is indirect development or metamorphosis
  • They have a chitinous exoskeleton.

Importance of exoskeleton to arthropods

  • It offers structural support
  • It prevents water loss since it is impermeable to water
  • It provides a system of levers for the muscle attachment
  • It is modified for the development of sensory structures like antennae
  • It is modified to provide flexibility at the joints
  • It undergoes ecdysis (moulting) for increase in the arthropods seize
  • It is modified for gaseous exchange e.g. the trachea system in insects or book lungs in arachnids.

Impacts of arthropods on human

Harmful effects of arthropods on humans




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