Invertebrate

As invertebrates or invertebrate (synonym: Evertebrata ) is any animal without a spinal column. At this informal group ( Formtaxon ) of living beings is one of the majority of all known animal species. The term was introduced in the early 19th century by Jean -Baptiste de Lamarck in contrast to the vertebrates ( Vertebrata ).

System

Invertebrates are not a homogeneous and natural affinity group. Besides a number of chordates ( Chordata ), one counts all non- chordate to the invertebrates. Including, inter alia, the following strains:

• Sponges ( Porifera )

• Water bears ( tardigrades )
• Arthropods ( Arthropoda )
• Hedgehog worms or star worms ( Echiurida )
• Calyx worms ( Kamptozoa )
• Arrow worms ( Chaetognata )
• Flatworms ( Platyhelminthes )
• Segmented worms ( Annelida )
• Tube worms ( Nemathelminthes )
• Ribbon worms ( Nemertini )
• Spray worms ( Sipunculida )
• Molluscs ( Mollusca )

New mouths except the vertebrates:

• Gill hole Animals ( Hemichrodata )
• Echinoderms ( Echinodermata )
• Chordates ( Chordata ) ( partial) Subphylum tunicates ( Tunicata Urochordata = )
• Subphylum Skull Loose ( Acrania )